Discovering ShaderToy

Découvrir ShaderToy

Christophe de Dinechin

AzurTech Winter 2024

Notre premier shader

            void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.5 + 0.5*cos(iTime+uv.xyx+vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Il n'y a rien à faire, ShaderToy pré-remplit!

La technique du singe

            void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Bidouillons les paramètres (Alt-Enter pour compiler)

Les vecteurs en GLSL

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Opérations sur 2, 3 ou 4 valeurs simultanément

Couleurs et coordonnées

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Couleur .rgba, Position .xyzw (quaternion)

Swizzling (agiter/mélanger)

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    vec3 col = 0.1 + 0.5*cos(0.5*iTime +
                             5.2*uv.xyx +
                             vec3(0,2,4));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Réarranger les coordonnées, .zyx, .bgr

Ajoutons une image

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0, uv).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0, uv).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0, uv).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

N'oubliez pas de choisir la texture pour iChannel0

Les textures sont des variables uniformes

Défilement

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0,
                       uv+vec2(0.1,0.2)*iTime).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0,
                       uv+vec2(0.1,0.2)*iTime).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Get image from texture
    vec3 col = texture(iChannel0,
                       uv+vec2(0.1,0.2)*iTime).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

On change la coordonnée "uv" (mapping)

Déformation

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * length(uv-0.5)
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * length(uv-0.5)
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * length(uv-0.5)
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * length(uv-0.5)
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
} void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * length(uv-0.5)
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Déformons le centre de l'image

Dépendance au temps

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
 
    // Compute displacement in texture
    vec3 col = texture(iChannel0,
                       (uv-0.5)
                       * pow(length(uv-0.5),
                             (sin(iTime)+1.0))
                       + 0.5).rgb;
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Animons la déformation

Créons une forme

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1);
    if (uv.x > uv.y)
        col = vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Calcul de la couleur en fonction des coordonnées

Créons un "cercle"

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1);
    if (length(uv) > 0.3)
        col = vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Cercle en fonction de la distance au centre

Ajustons les coordonnées

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.y *= iResolution.y / iResolution.x;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1);
    if (length(uv) > 0.3)
        col = vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Les résolutions X et Y ne sont pas égales

Ajustons les coordonnées

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1);
    if (length(uv) > 0.3)
        col = vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

La dimension selon Y est plus grande

La fonction step

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1)
        + step(0.3, length(uv))
        * vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1)
        + step(0.3, length(uv))
        * vec3(1, 0, 0);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Pourquoi on obtient des couleurs Microsoft?

La fonction smoothstep

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1)
        + smoothstep(0.3, 0.4,
                     length(uv))
        * vec3(1, 0.5, -1);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Création de transitions douces

Animons le cercle

            void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    uv += vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 1)
        + smoothstep(0.3, 0.4, length(uv))
        * vec3(1, 0.5, -1);
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Création de transitions douces

Un fonction cercle

            vec3 circle(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    return fg
        + step(radius, length(uv - center))
        * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    col = circle(uv, 0.3, center, col, vec3(0.5, 0.8, 0));
    col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          vec3 circle(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    return fg
        + step(radius, length(uv - center))
        * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    col = circle(uv, 0.3, center, col, vec3(0.5, 0.8, 0));
    col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} vec3 circle(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    return fg
        + step(radius, length(uv - center))
        * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    col = circle(uv, 0.3, center, col, vec3(0.5, 0.8, 0));
    col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Réutiliser des formes

Et les textures?

            vec3 circle(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    return fg
        + step(radius, length(uv - center))
        * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = circle(uv, 0.3, center, col, tex);
    col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

La couleur est calculée par pixel

Répétitions

            vec3 circle(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    return fg
        + step(radius, length(uv - center))
        * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    vec2 uvrep = mod(uv*5.0+0.5,1.0)-0.5;
    col = circle(uvrep, 0.3, center, col, tex);
    col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Répéter une forme ne coûte rien

Dessiner un carré

            vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv - center);
    float s = length(step(radius, d));
    return fg + step(1.0, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, center, col, tex);
    col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv - center);
    float s = length(step(radius, d));
    return fg + step(1.0, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, center, col, tex);
    col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
} vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv - center);
    float s = length(step(radius, d));
    return fg + step(1.0, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, center, col, tex);
    col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

On a une fonction de distance

Dessiner un carré arrondi

            vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv-center)-0.4*radius;
    float s = length(max(d, 0.0));
    return fg + step(0.2*radius, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, center, col, tex);
    col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Une autre fonction de distance

Dessiner un quadrifolio

            vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv-center)-0.5*radius;
    float s = length(max(d, -0.5));
    return fg + step(0.7*radius, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, center, col, tex);
    col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Encore une autre fonction de distance

Animations indépendantes

            vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv-center)-0.4*radius;
    float s = length(max(d, 0.0));
    return fg + step(0.2*radius, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 c1 = vec2(sin(iTime), cos(iTime)) * 0.1;
    vec2 c2 = vec2(sin(2.3*iTime), cos(2.6*iTime)) * 0.2;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    col = square(uv, 0.3, c1, col, tex);
    col = square(uv, 0.1, c2, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

On peut déplacer indépendamment les éléments

Rotation

            vec2 rotate(vec2 uv, float a)
{
    mat2 rot = mat2(cos(a), sin(a), -sin(a), cos(a));
    return rot * uv;
}
vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv-center)-0.4*radius;
    float s = length(max(d, 0.0));
    return fg + step(0.2*radius, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 c1 = vec2(sin(iTime), cos(iTime)) * 0.1;
    vec2 c2 = vec2(sin(2.3*iTime), cos(2.6*iTime)) * 0.2;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    vec2 urot = rotate(uv-c1, 3.2*iTime)+c1;
    col = square(urot, 0.3, c1, col, tex);
    col = square(uv, 0.1, c2, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}
          vec2 rotate(vec2 uv, float a)
{
    mat2 rot = mat2(cos(a), sin(a), -sin(a), cos(a));
    return rot * uv;
}
vec3 square(vec2 uv, float radius, vec2 center,
            vec3 bg, vec3 fg)
{
    vec2 d = abs(uv-center)-0.4*radius;
    float s = length(max(d, 0.0));
    return fg + step(0.2*radius, s) * (bg - fg);
}
void mainImage(out vec4 fragColor,
               in vec2 fragCoord)
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy - 0.5;
    uv.x *= iResolution.x / iResolution.y;
    vec2 c1 = vec2(sin(iTime), cos(iTime)) * 0.1;
    vec2 c2 = vec2(sin(2.3*iTime), cos(2.6*iTime)) * 0.2;
 
    // Compute color based on position
    vec3 col = vec3(0, 0, 0);
    vec3 tex = texture(iChannel0, uv+0.5).rgb;
    vec2 urot = rotate(uv-c1, 3.2*iTime)+c1;
    col = square(urot, 0.3, c1, col, tex);
    col = square(uv, 0.1, c2, col, vec3(1,0.5,0));
 
    // Output to screen
    fragColor = vec4(col,1.0);
}

Bouger les objets en bougeant l'espace!!!

La même chose en 3D

            void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
}
          void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 position = fragCoord.xy / resolution.xy - 0.5;
    position.x *= resolution.x / resolution.y;
    float angle = mouse.x * 0.1 - 30.1;
    float radius = 8.5 - 0.02 * mouse.y;
 
    float ss = sin(angle * todeg);
    float cc = cos(angle * todeg);
    vec3 org = vec3(ss*radius,2.0,cc*radius);
    vec3 dir = normalize(vec3(position.x*cc-ss,position.y, -position.x*ss-cc));
 
    vec3 center = vec3(-1.0, sin(0.1*time)*1.0+1.5, 2.75);
    sphere[0].c   = center;
    sphere[0].r   = 0.5;
    sphere[0].col = vec4(1,0.5,0.3, 0.5);
 
    const float sixtieth = 1.0 / 60.0;
    const float secminfac = 2.0 * 3.1415965358 * sixtieth;
    const float hourfac = secminfac * 5.0;
 
    float seca = seconds * secminfac;
    sphere[1].c   = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
    sphere[1].r   = 0.2;
    sphere[1].col = vec4(0.3,1,0.3, 2.5);
 
    float mina = minutes * secminfac;
    sphere[2].c   = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
    sphere[2].r   = 0.3;
    sphere[2].col = vec4(0.43,0.3,1, 0.0);
 
    float hrsa = hours * hourfac;
    sphere[3].c   = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
    sphere[3].r   = 0.2;
    sphere[3].col = vec4(0.8,0.0,0.0, 0.1);
 
    cube[0].c = vec3(-1.0, 0.5, 1.5);
    cube[0].h_side = vec3(0.5, 3.0, 1.0);
    cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);
 
    plane[0].p = vec3(0,-0.5, 0);
    plane[0].n = vec3(0, 1.0, 0);
    plane[0].col1 = vec4(0.6,0.8,1, 0.0);
    plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);
 
    plane[1].p = vec3(0,0, -2.5);
    plane[1].n = vec3(0.0, 0, 1.0);
    plane[1].col1 = vec4(0,0,0.3, 0.0);
    plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);
 
    Ray r;
    r.org = org;
    r.dir = dir;
    vec4 col = vec4(0,0,0,1);
    float eps  = 0.0001;
    vec4 bcol = vec4(1,1,1,1);
    for (int j = 0; j < raytraceDepth; j++)
    {
        Intersection i;
        i.hit = 0;
        i.t = 1e30;
        i.n = i.p = vec3(0);
        i.col = vec4(0);
 
        Intersect(r, i);
        if (i.hit != 0)
        {
            vec4 shadow = computeLightShadow(i);
            col += bcol * i.col * shadow;
            bcol *= i.col / (1.0 + i.col.a * i.t + shadow.a);
        }
        else
        {
            break;
        }
 
        r.org = vec3(i.p.x + eps * i.n.x,
                     i.p.y + eps * i.n.y,
                     i.p.z + eps * i.n.z);
        r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
    }
    col.a = 1.0;
    fragColor = col;
}
void Intersect(Ray r, inout Intersection i)
{
    sphere_intersect(sphere[0], r, i);
    sphere_intersect(sphere[1], r, i);
    sphere_intersect(sphere[2], r, i);
    sphere_intersect(sphere[3], r, i);
 
    cube_intersect(cube[0], r, i);
 
    plane_intersect(plane[0], r, i);
 
    cubes_intersect(0.0, r, i);
}

Lancer de rayons: on déplace uv en 3D

Raymarching

            void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}
          void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
} void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 mo = iMouse.xy/iResolution.xy;
    float time = 32.0 + iTime*1.5;
 
    // camera
    vec3 ta = vec3( 0.25, -0.75, -0.75 );
    vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 2.2, 4.5*sin(0.1*time + 7.0*mo.x) );
    // camera-to-world transformation
    mat3 ca = setCamera( ro, ta, 0.0 );
 
    vec3 tot = vec3(0.0);
    vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
 
    // focal length
    const float fl = 2.5;
 
    // ray direction
    vec3 rd = ca * normalize( vec3(p,fl) );
 
    // ray differentials
    vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
    vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
    vec3 rdx = ca * normalize( vec3(px,fl) );
    vec3 rdy = ca * normalize( vec3(py,fl) );
 
    // render
    vec3 col = render( ro, rd, rdx, rdy );
 
    // gain
    // col = col*3.0/(2.5+col);
 
    // gamma
    col = pow( col, vec3(0.4545) );
 
    tot += col;
    fragColor = vec4( tot, 1.0 );
}
 
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
    // background
    vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
 
    // raycast scene
    vec2 res = raycast(ro,rd);
    float t = res.x;
    float m = res.y;
    if( m>-0.5 )
    {
        vec3 pos = ro + t*rd;
        vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
        vec3 ref = reflect( rd, nor );
 
        // material
        col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
        float ks = 1.0;
 
        if( m<1.5 )
        {
            // project pixel footprint into the plane
            vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
            vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
 
            float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
            col = 0.15 + f*vec3(0.05);
            ks = 0.4;
        }
 
        // lighting
        float occ = calcAO( pos, nor );
 
        vec3 lin = vec3(0.0);
 
        // sun
        {
            vec3  lig = normalize( vec3(-0.5, 0.4, -0.6) );
            vec3  hal = normalize( lig-rd );
            float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
            //if( dif>0.0001 )
            dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
            float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
            //spe *= 0.04+0.96*pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
            lin += col*2.20*dif*vec3(1.30,1.00,0.70);
            lin +=     5.00*spe*vec3(1.30,1.00,0.70)*ks;
        }
        // sky
        {
            float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
            dif *= occ;
            float spe = smoothstep( -0.2, 0.2, ref.y );
            spe *= dif;
            spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
            //if( spe>0.001 )
            spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
            lin += col*0.60*dif*vec3(0.40,0.60,1.15);
            lin +=     2.00*spe*vec3(0.40,0.60,1.30)*ks;
        }
        // back
        {
            float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
            dif *= occ;
            lin += col*0.55*dif*vec3(0.25,0.25,0.25);
        }
        // sss
        {
            float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
            dif *= occ;
            lin += col*0.25*dif*vec3(1.00,1.00,1.00);
        }
 
        col = lin;
 
        col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
    }
 
    return vec3( clamp(col,0.0,1.0) );
}
 
vec2 raycast( in vec3 ro, in vec3 rd )
{
    vec2 res = vec2(-1.0,-1.0);
 
    float tmin = 1.0;
    float tmax = 20.0;
 
    // raytrace floor plane
    float tp1 = (0.0-ro.y)/rd.y;
    if( tp1>0.0 )
    {
        tmax = min( tmax, tp1 );
        res = vec2( tp1, 1.0 );
    }
    //else return res;
 
    // raymarch primitives
    vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
    if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
    {
        //return vec2(tb.x,2.0);
        tmin = max(tb.x,tmin);
        tmax = min(tb.y,tmax);
 
        float t = tmin;
        for( int i=0; i<70 && t<tmax; i++ )
        {
            vec2 h = map( ro+rd*t );
            if( abs(h.x)<(0.0001*t) )
            {
                res = vec2(t,h.y);
                break;
            }
            t += h.x;
        }
    }
 
    return res;
}
 
vec2 map( in vec3 pos )
{
    vec2 res = vec2( pos.y, 0.0 );
 
    // bounding box
    if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
    {
        res = opU( res, vec2( sdSphere(    pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
        res = opU( res, vec2( sdRhombus(  (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
        res = opU( res, vec2( sdBoxFrame(    pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
        res = opU( res, vec2( sdCone(        pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
        res = opU( res, vec2( sdSolidAngle(  pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdTorus(      (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
        res = opU( res, vec2( sdBox(         pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
        res = opU( res, vec2( sdCapsule(     pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1  ), 31.9 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
        res = opU( res, vec2( sdHexPrism(    pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
    {
        res = opU( res, vec2( sdPyramid(    pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
        res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
        res = opU( res, vec2( sdTriPrism(   pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
        res = opU( res, vec2( sdEllipsoid(  pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
        res = opU( res, vec2( sdHorseshoe(  pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
    }
 
    // bounding box
    if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
    {
        res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
        res = opU( res, vec2( sdCylinder(    pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
        res = opU( res, vec2( sdCappedCone(  pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
        res = opU( res, vec2( sdRoundCone(   pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
    }
 
    return res;
}
 
vec2 opU( vec2 d1, vec2 d2 )
{
   return (d1.x<d2.x) ? d1 : d2;
}
 
float sdPyramid( in vec3 p, in float h )
{
    float m2 = h*h + 0.25;
 
    // symmetry
    p.xz = abs(p.xz);
    p.xz = (p.z>p.x) ? p.zx : p.xz;
    p.xz -= 0.5;
 
    // project into face plane (2D)
    vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
 
    float s = max(-q.x,0.0);
    float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
 
    float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
   float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
 
    float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
 
    // recover 3D and scale, and add sign
    return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));;
 
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
    p = abs(p);
    vec2 b = vec2(la,lb);
    float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
    vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
    return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
 
float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
{
    p.x = abs(p.x);
    float l = length(p.xy);
    p.xy = mat2(-c.x, c.y,
                c.y, c.x)*p.xy;
    p.xy = vec2((p.y>0.0 || p.x>0.0)?p.x:l*sign(-c.x),
                (p.x>0.0)?p.y:l );
    p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);
 
    vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
    vec2 d = abs(q) - w;
    return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

Déplacement du rayon pas à pas

Textures procédurales

            // materials
vec4 mate = vec4(0.0);
vec2 mate2 = vec2(1.0,1.0);
if( tmat.z<0.5 )
{
    nor = vec3(0.0,1.0,0.0);
    ref = reflect( rd, nor );
    mate.xyz = vec3(1.0);
    mate2.y = 1.0 - 0.9*(2.0/(2.0+dot(pos.xz,pos.xz)));
}
else if( tmat.z<1.5 )
{
    mate2.x = 4.0;
    mate = vec4(0.16,0.32,0.0,0.8);
 
    float f = texturize( iChannel0, 0.15*pos, nor ).x * texturize( iChannel0, 0.2*0.25*pos, nor ).x;
    mate.xyz = mix( 0.56*mate.xyz, vec3(0.21,0.28,0.0), f );
 
    f = texturize( iChannel0, pos, nor ).x * texturize( iChannel0, 0.25*pos, nor ).x;
    f = f*f;
    mate.xyz = mix( mate.xyz, vec3(0.21,0.28,0.0), 0.6*f );
 
    vec3 bnor = -1.0+2.0*texturize( iChannel0, 4.0*pos, nor );
    nor = normalize( nor + 0.15*bnor );
}
else if( tmat.z<2.5 )
{
    vec3 q = pos-vec3(0.0,1.8,0.0) - vec3(0.0,0.44,0.35);
 
    float an2 = an + 0.015*(-1.0+2.0*noise( 6.0*iTime ));
    vec3 oq = q;
    q.x += -2.0*0.15*clamp(sin(an2),-0.42,0.42);
    float f = length( q.xy );
 
    mate2.y = 1.0-smoothstep(0.24,0.35,length( oq.xy-vec2(0.0,0.035) ));
    mate = vec4(0.5,0.5,0.5,1.0);
    mate.xyz = mix( mate.xyz, vec3(0.6,0.4,0.3), 0.5*smoothstep(0.1,0.4,f) );
 
    vec3 c1 = vec3(0.0,0.15,0.05)*(1.0-0.85*f/0.19);
    float a = atan(q.y,-q.x);
    float te = fbm( 20.0*vec2(0.3*a,1.0*f) );
    c1 *= 0.3 + 5.0*te;
 
    c1 += vec3(0.5,1.0,0.1)*0.35*(0.5+te)*
        (1.0-smoothstep( 0.3,1.2,abs(a+0.5)))*
        (1.0-smoothstep( 0.0, 0.06, abs(f-0.125) ));
 
    mate.xyz = mix( mate.xyz, c1, 1.0-smoothstep( 0.18, 0.19, f ) );
 
    oq.x += -2.0*0.19*clamp(sin(an2),-0.42,0.42);
    f = length( oq.xy );
    mate.xyz *= smoothstep( 0.07, 0.10, f );
    mate.xyz *= 1.0-0.2*vec3(0.5,0.9,1.0)*smoothstep( 0.2, 0.4, f );
 
    mate.w = 2.0;
    mate2.x = 64.0;
}
else if( tmat.z<3.5 )
{
    mate = 0.8*vec4(0.85,0.7,0.6,0.0);
    mate2.x = 0.0;
    float f = smoothstep( 0.0, 0.1, 0.5*abs(pos.x)+pos.y-3.02 );
    mate.xyz *= 1.0 - 0.8*vec3( f );
    mate.xyz *= 0.2 + 0.8*smoothstep( 0.0, 1.0, texturize( iChannel0, 0.1*2.1*pos*vec3(4.0,0.1,4.0), nor ).x );
}
else if( tmat.z<4.5 )
{
    float z = smoothstep( 0.0, 2.0, pos.z+0.5 );
    mate = 0.5*vec4(0.5,0.25,0.1,0.0);
    mate.x += 0.1*(1.0-z);
    mate2.y = z;
          // materials
vec4 mate = vec4(0.0);
vec2 mate2 = vec2(1.0,1.0);
if( tmat.z<0.5 )
{
    nor = vec3(0.0,1.0,0.0);
    ref = reflect( rd, nor );
    mate.xyz = vec3(1.0);
    mate2.y = 1.0 - 0.9*(2.0/(2.0+dot(pos.xz,pos.xz)));
}
else if( tmat.z<1.5 )
{
    mate2.x = 4.0;
    mate = vec4(0.16,0.32,0.0,0.8);
 
    float f = texturize( iChannel0, 0.15*pos, nor ).x * texturize( iChannel0, 0.2*0.25*pos, nor ).x;
    mate.xyz = mix( 0.56*mate.xyz, vec3(0.21,0.28,0.0), f );
 
    f = texturize( iChannel0, pos, nor ).x * texturize( iChannel0, 0.25*pos, nor ).x;
    f = f*f;
    mate.xyz = mix( mate.xyz, vec3(0.21,0.28,0.0), 0.6*f );
 
    vec3 bnor = -1.0+2.0*texturize( iChannel0, 4.0*pos, nor );
    nor = normalize( nor + 0.15*bnor );
}
else if( tmat.z<2.5 )
{
    vec3 q = pos-vec3(0.0,1.8,0.0) - vec3(0.0,0.44,0.35);
 
    float an2 = an + 0.015*(-1.0+2.0*noise( 6.0*iTime ));
    vec3 oq = q;
    q.x += -2.0*0.15*clamp(sin(an2),-0.42,0.42);
    float f = length( q.xy );
 
    mate2.y = 1.0-smoothstep(0.24,0.35,length( oq.xy-vec2(0.0,0.035) ));
    mate = vec4(0.5,0.5,0.5,1.0);
    mate.xyz = mix( mate.xyz, vec3(0.6,0.4,0.3), 0.5*smoothstep(0.1,0.4,f) );
 
    vec3 c1 = vec3(0.0,0.15,0.05)*(1.0-0.85*f/0.19);
    float a = atan(q.y,-q.x);
    float te = fbm( 20.0*vec2(0.3*a,1.0*f) );
    c1 *= 0.3 + 5.0*te;
 
    c1 += vec3(0.5,1.0,0.1)*0.35*(0.5+te)*
        (1.0-smoothstep( 0.3,1.2,abs(a+0.5)))*
        (1.0-smoothstep( 0.0, 0.06, abs(f-0.125) ));
 
    mate.xyz = mix( mate.xyz, c1, 1.0-smoothstep( 0.18, 0.19, f ) );
 
    oq.x += -2.0*0.19*clamp(sin(an2),-0.42,0.42);
    f = length( oq.xy );
    mate.xyz *= smoothstep( 0.07, 0.10, f );
    mate.xyz *= 1.0-0.2*vec3(0.5,0.9,1.0)*smoothstep( 0.2, 0.4, f );
 
    mate.w = 2.0;
    mate2.x = 64.0;
}
else if( tmat.z<3.5 )
{
    mate = 0.8*vec4(0.85,0.7,0.6,0.0);
    mate2.x = 0.0;
    float f = smoothstep( 0.0, 0.1, 0.5*abs(pos.x)+pos.y-3.02 );
    mate.xyz *= 1.0 - 0.8*vec3( f );
    mate.xyz *= 0.2 + 0.8*smoothstep( 0.0, 1.0, texturize( iChannel0, 0.1*2.1*pos*vec3(4.0,0.1,4.0), nor ).x );
}
else if( tmat.z<4.5 )
{
    float z = smoothstep( 0.0, 2.0, pos.z+0.5 );
    mate = 0.5*vec4(0.5,0.25,0.1,0.0);
    mate.x += 0.1*(1.0-z);
    mate2.y = z; // materials
vec4 mate = vec4(0.0);
vec2 mate2 = vec2(1.0,1.0);
if( tmat.z<0.5 )
{
    nor = vec3(0.0,1.0,0.0);
    ref = reflect( rd, nor );
    mate.xyz = vec3(1.0);
    mate2.y = 1.0 - 0.9*(2.0/(2.0+dot(pos.xz,pos.xz)));
}
else if( tmat.z<1.5 )
{
    mate2.x = 4.0;
    mate = vec4(0.16,0.32,0.0,0.8);
 
    float f = texturize( iChannel0, 0.15*pos, nor ).x * texturize( iChannel0, 0.2*0.25*pos, nor ).x;
    mate.xyz = mix( 0.56*mate.xyz, vec3(0.21,0.28,0.0), f );
 
    f = texturize( iChannel0, pos, nor ).x * texturize( iChannel0, 0.25*pos, nor ).x;
    f = f*f;
    mate.xyz = mix( mate.xyz, vec3(0.21,0.28,0.0), 0.6*f );
 
    vec3 bnor = -1.0+2.0*texturize( iChannel0, 4.0*pos, nor );
    nor = normalize( nor + 0.15*bnor );
}
else if( tmat.z<2.5 )
{
    vec3 q = pos-vec3(0.0,1.8,0.0) - vec3(0.0,0.44,0.35);
 
    float an2 = an + 0.015*(-1.0+2.0*noise( 6.0*iTime ));
    vec3 oq = q;
    q.x += -2.0*0.15*clamp(sin(an2),-0.42,0.42);
    float f = length( q.xy );
 
    mate2.y = 1.0-smoothstep(0.24,0.35,length( oq.xy-vec2(0.0,0.035) ));
    mate = vec4(0.5,0.5,0.5,1.0);
    mate.xyz = mix( mate.xyz, vec3(0.6,0.4,0.3), 0.5*smoothstep(0.1,0.4,f) );
 
    vec3 c1 = vec3(0.0,0.15,0.05)*(1.0-0.85*f/0.19);
    float a = atan(q.y,-q.x);
    float te = fbm( 20.0*vec2(0.3*a,1.0*f) );
    c1 *= 0.3 + 5.0*te;
 
    c1 += vec3(0.5,1.0,0.1)*0.35*(0.5+te)*
        (1.0-smoothstep( 0.3,1.2,abs(a+0.5)))*
        (1.0-smoothstep( 0.0, 0.06, abs(f-0.125) ));
 
    mate.xyz = mix( mate.xyz, c1, 1.0-smoothstep( 0.18, 0.19, f ) );
 
    oq.x += -2.0*0.19*clamp(sin(an2),-0.42,0.42);
    f = length( oq.xy );
    mate.xyz *= smoothstep( 0.07, 0.10, f );
    mate.xyz *= 1.0-0.2*vec3(0.5,0.9,1.0)*smoothstep( 0.2, 0.4, f );
 
    mate.w = 2.0;
    mate2.x = 64.0;
}
else if( tmat.z<3.5 )
{
    mate = 0.8*vec4(0.85,0.7,0.6,0.0);
    mate2.x = 0.0;
    float f = smoothstep( 0.0, 0.1, 0.5*abs(pos.x)+pos.y-3.02 );
    mate.xyz *= 1.0 - 0.8*vec3( f );
    mate.xyz *= 0.2 + 0.8*smoothstep( 0.0, 1.0, texturize( iChannel0, 0.1*2.1*pos*vec3(4.0,0.1,4.0), nor ).x );
}
else if( tmat.z<4.5 )
{
    float z = smoothstep( 0.0, 2.0, pos.z+0.5 );
    mate = 0.5*vec4(0.5,0.25,0.1,0.0);
    mate.x += 0.1*(1.0-z);
    mate2.y = z; // materials
vec4 mate = vec4(0.0);
vec2 mate2 = vec2(1.0,1.0);
if( tmat.z<0.5 )
{
    nor = vec3(0.0,1.0,0.0);
    ref = reflect( rd, nor );
    mate.xyz = vec3(1.0);
    mate2.y = 1.0 - 0.9*(2.0/(2.0+dot(pos.xz,pos.xz)));
}
else if( tmat.z<1.5 )
{
    mate2.x = 4.0;
    mate = vec4(0.16,0.32,0.0,0.8);
 
    float f = texturize( iChannel0, 0.15*pos, nor ).x * texturize( iChannel0, 0.2*0.25*pos, nor ).x;
    mate.xyz = mix( 0.56*mate.xyz, vec3(0.21,0.28,0.0), f );
 
    f = texturize( iChannel0, pos, nor ).x * texturize( iChannel0, 0.25*pos, nor ).x;
    f = f*f;
    mate.xyz = mix( mate.xyz, vec3(0.21,0.28,0.0), 0.6*f );
 
    vec3 bnor = -1.0+2.0*texturize( iChannel0, 4.0*pos, nor );
    nor = normalize( nor + 0.15*bnor );
}
else if( tmat.z<2.5 )
{
    vec3 q = pos-vec3(0.0,1.8,0.0) - vec3(0.0,0.44,0.35);
 
    float an2 = an + 0.015*(-1.0+2.0*noise( 6.0*iTime ));
    vec3 oq = q;
    q.x += -2.0*0.15*clamp(sin(an2),-0.42,0.42);
    float f = length( q.xy );
 
    mate2.y = 1.0-smoothstep(0.24,0.35,length( oq.xy-vec2(0.0,0.035) ));
    mate = vec4(0.5,0.5,0.5,1.0);
    mate.xyz = mix( mate.xyz, vec3(0.6,0.4,0.3), 0.5*smoothstep(0.1,0.4,f) );
 
    vec3 c1 = vec3(0.0,0.15,0.05)*(1.0-0.85*f/0.19);
    float a = atan(q.y,-q.x);
    float te = fbm( 20.0*vec2(0.3*a,1.0*f) );
    c1 *= 0.3 + 5.0*te;
 
    c1 += vec3(0.5,1.0,0.1)*0.35*(0.5+te)*
        (1.0-smoothstep( 0.3,1.2,abs(a+0.5)))*
        (1.0-smoothstep( 0.0, 0.06, abs(f-0.125) ));
 
    mate.xyz = mix( mate.xyz, c1, 1.0-smoothstep( 0.18, 0.19, f ) );
 
    oq.x += -2.0*0.19*clamp(sin(an2),-0.42,0.42);
    f = length( oq.xy );
    mate.xyz *= smoothstep( 0.07, 0.10, f );
    mate.xyz *= 1.0-0.2*vec3(0.5,0.9,1.0)*smoothstep( 0.2, 0.4, f );
 
    mate.w = 2.0;
    mate2.x = 64.0;
}
else if( tmat.z<3.5 )
{
    mate = 0.8*vec4(0.85,0.7,0.6,0.0);
    mate2.x = 0.0;
    float f = smoothstep( 0.0, 0.1, 0.5*abs(pos.x)+pos.y-3.02 );
    mate.xyz *= 1.0 - 0.8*vec3( f );
    mate.xyz *= 0.2 + 0.8*smoothstep( 0.0, 1.0, texturize( iChannel0, 0.1*2.1*pos*vec3(4.0,0.1,4.0), nor ).x );
}
else if( tmat.z<4.5 )
{
    float z = smoothstep( 0.0, 2.0, pos.z+0.5 );
    mate = 0.5*vec4(0.5,0.25,0.1,0.0);
    mate.x += 0.1*(1.0-z);
    mate2.y = z;

Les textures aussi sont calculées

Textures volumétriques

            // this is the first time i've tried to make a short code
 
#define V vec3
 
float f(V p) {
    return max(0.,1.1-length(p)-.1*texture(iChannel0,p.xy).r-.04*sin(sin(4.*p.x)+15.*p.y+6.*iTime));
}
 
void mainImage(out vec4 c, vec2 p) {
    V r = iResolution,
    d = V(fract((p-.5*r.xy)/r.y*2.2)-.5,1),
    o = d*2.3-V(0,0,3),
    a = V(5);
 
    c *= 0.;
    for (int i=0; i<32; i++) {
        c.rgb += (a*=mix(V(.9,1,.8),mix(mix(V(1,.9,.8),V(.8,.9,1),step(p.x,.5*r.x)),V(1,.8,.9),step(p.x,r.x/4.)),step(p.x,r.x*.75))-f(o+=d*.05)/3.)*max(0.,(f(o)-f(o+.07)));
    }
    c = sqrt(c/(1.+c));
}
          // this is the first time i've tried to make a short code
 
#define V vec3
 
float f(V p) {
    return max(0.,1.1-length(p)-.1*texture(iChannel0,p.xy).r-.04*sin(sin(4.*p.x)+15.*p.y+6.*iTime));
}
 
void mainImage(out vec4 c, vec2 p) {
    V r = iResolution,
    d = V(fract((p-.5*r.xy)/r.y*2.2)-.5,1),
    o = d*2.3-V(0,0,3),
    a = V(5);
 
    c *= 0.;
    for (int i=0; i<32; i++) {
        c.rgb += (a*=mix(V(.9,1,.8),mix(mix(V(1,.9,.8),V(.8,.9,1),step(p.x,.5*r.x)),V(1,.8,.9),step(p.x,r.x/4.)),step(p.x,r.x*.75))-f(o+=d*.05)/3.)*max(0.,(f(o)-f(o+.07)));
    }
    c = sqrt(c/(1.+c));
} // this is the first time i've tried to make a short code
 
#define V vec3
 
float f(V p) {
    return max(0.,1.1-length(p)-.1*texture(iChannel0,p.xy).r-.04*sin(sin(4.*p.x)+15.*p.y+6.*iTime));
}
 
void mainImage(out vec4 c, vec2 p) {
    V r = iResolution,
    d = V(fract((p-.5*r.xy)/r.y*2.2)-.5,1),
    o = d*2.3-V(0,0,3),
    a = V(5);
 
    c *= 0.;
    for (int i=0; i<32; i++) {
        c.rgb += (a*=mix(V(.9,1,.8),mix(mix(V(1,.9,.8),V(.8,.9,1),step(p.x,.5*r.x)),V(1,.8,.9),step(p.x,r.x/4.)),step(p.x,r.x*.75))-f(o+=d*.05)/3.)*max(0.,(f(o)-f(o+.07)));
    }
    c = sqrt(c/(1.+c));
} // this is the first time i've tried to make a short code
 
#define V vec3
 
float f(V p) {
    return max(0.,1.1-length(p)-.1*texture(iChannel0,p.xy).r-.04*sin(sin(4.*p.x)+15.*p.y+6.*iTime));
}
 
void mainImage(out vec4 c, vec2 p) {
    V r = iResolution,
    d = V(fract((p-.5*r.xy)/r.y*2.2)-.5,1),
    o = d*2.3-V(0,0,3),
    a = V(5);
 
    c *= 0.;
    for (int i=0; i<32; i++) {
        c.rgb += (a*=mix(V(.9,1,.8),mix(mix(V(1,.9,.8),V(.8,.9,1),step(p.x,.5*r.x)),V(1,.8,.9),step(p.x,r.x/4.)),step(p.x,r.x*.75))-f(o+=d*.05)/3.)*max(0.,(f(o)-f(o+.07)));
    }
    c = sqrt(c/(1.+c));
}

445 caractères de code

Découvrir ShaderToy Christophe de Dinechin AzurTech Winter 2024

	void mainImage(out vec4 fragColor, in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy;

	vec3 col = 0.5 + 0.5*cos(iTime+uv.xyx+vec3(0,2,4));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy;

	vec3 col = 0.1 + 0.5cos(0.5iTime +
	5.2*uv.xyx +
	vec3(0,2,4));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	vec3 circle(vec2 uv, float radius, vec2 center,
	vec3 bg, vec3 fg)
	{
	return fg
	+ step(radius, length(uv - center))
	* (bg - fg);
	}
	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy - 0.5;
	uv.x *= iResolution.x / iResolution.y;
	vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;

	// Compute color based on position
	vec3 col = vec3(0, 0, 0);
	col = circle(uv, 0.3, center, col, vec3(0.5, 0.8, 0));
	col = circle(uv, 0.1, -1.5*center, col, vec3(1, 0.5, 0));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	vec3 square(vec2 uv, float radius, vec2 center,
	vec3 bg, vec3 fg)
	{
	vec2 d = abs(uv - center);
	float s = length(step(radius, d));
	return fg + step(1.0, s) * (bg - fg);
	}
	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy - 0.5;
	uv.x *= iResolution.x / iResolution.y;
	vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;

	// Compute color based on position
	vec3 col = vec3(0, 0, 0);
	vec3 tex = texture(iChannel0, uv+0.5).rgb;
	col = square(uv, 0.3, center, col, tex);
	col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	vec3 square(vec2 uv, float radius, vec2 center,
	vec3 bg, vec3 fg)
	{
	vec2 d = abs(uv-center)-0.4*radius;
	float s = length(max(d, 0.0));
	return fg + step(0.2radius, s) (bg - fg);
	}
	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy - 0.5;
	uv.x *= iResolution.x / iResolution.y;
	vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;

	// Compute color based on position
	vec3 col = vec3(0, 0, 0);
	vec3 tex = texture(iChannel0, uv+0.5).rgb;
	col = square(uv, 0.3, center, col, tex);
	col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	vec3 square(vec2 uv, float radius, vec2 center,
	vec3 bg, vec3 fg)
	{
	vec2 d = abs(uv-center)-0.5*radius;
	float s = length(max(d, -0.5));
	return fg + step(0.7radius, s) (bg - fg);
	}
	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy - 0.5;
	uv.x *= iResolution.x / iResolution.y;
	vec2 center = vec2(sin(iTime), cos(iTime)) * 0.1;

	// Compute color based on position
	vec3 col = vec3(0, 0, 0);
	vec3 tex = texture(iChannel0, uv+0.5).rgb;
	col = square(uv, 0.3, center, col, tex);
	col = square(uv, 0.1, -1.5*center, col, vec3(1,0.5,0));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	vec2 rotate(vec2 uv, float a)
	{
	mat2 rot = mat2(cos(a), sin(a), -sin(a), cos(a));
	return rot * uv;
	}
	vec3 square(vec2 uv, float radius, vec2 center,
	vec3 bg, vec3 fg)
	{
	vec2 d = abs(uv-center)-0.4*radius;
	float s = length(max(d, 0.0));
	return fg + step(0.2radius, s) (bg - fg);
	}
	void mainImage(out vec4 fragColor,
	in vec2 fragCoord)
	{
	// Normalized pixel coordinates (from 0 to 1)
	vec2 uv = fragCoord/iResolution.xy - 0.5;
	uv.x *= iResolution.x / iResolution.y;
	vec2 c1 = vec2(sin(iTime), cos(iTime)) * 0.1;
	vec2 c2 = vec2(sin(2.3iTime), cos(2.6iTime)) * 0.2;

	// Compute color based on position
	vec3 col = vec3(0, 0, 0);
	vec3 tex = texture(iChannel0, uv+0.5).rgb;
	vec2 urot = rotate(uv-c1, 3.2*iTime)+c1;
	col = square(urot, 0.3, c1, col, tex);
	col = square(uv, 0.1, c2, col, vec3(1,0.5,0));

	// Output to screen
	fragColor = vec4(col,1.0);
	}

	void mainImage( out vec4 fragColor, in vec2 fragCoord )
	{
	vec2 position = fragCoord.xy / resolution.xy - 0.5;
	position.x *= resolution.x / resolution.y;
	float angle = mouse.x * 0.1 - 30.1;
	float radius = 8.5 - 0.02 * mouse.y;

	float ss = sin(angle * todeg);
	float cc = cos(angle * todeg);
	vec3 org = vec3(ssradius,2.0,ccradius);
	vec3 dir = normalize(vec3(position.xcc-ss,position.y, -position.xss-cc));

	vec3 center = vec3(-1.0, sin(0.1time)1.0+1.5, 2.75);
	sphere[0].c = center;
	sphere[0].r = 0.5;
	sphere[0].col = vec4(1,0.5,0.3, 0.5);

	const float sixtieth = 1.0 / 60.0;
	const float secminfac = 2.0 * 3.1415965358 * sixtieth;
	const float hourfac = secminfac * 5.0;

	float seca = seconds * secminfac;
	sphere[1].c = center + 0.6 * vec3(sin(seca), cos(seca), 1.0);
	sphere[1].r = 0.2;
	sphere[1].col = vec4(0.3,1,0.3, 2.5);

	float mina = minutes * secminfac;
	sphere[2].c = center + 0.7 * vec3(sin(mina), cos(mina), 0.0);
	sphere[2].r = 0.3;
	sphere[2].col = vec4(0.43,0.3,1, 0.0);

	float hrsa = hours * hourfac;
	sphere[3].c = center + 0.5 * vec3(sin(hrsa), cos(hrsa), 0.5);
	sphere[3].r = 0.2;
	sphere[3].col = vec4(0.8,0.0,0.0, 0.1);

	cube[0].c = vec3(-1.0, 0.5, 1.5);
	cube[0].h_side = vec3(0.5, 3.0, 1.0);
	cube[0].col = vec4(1.0, 0.8, 0.7, 3.1);

	plane[0].p = vec3(0,-0.5, 0);
	plane[0].n = vec3(0, 1.0, 0);
	plane[0].col1 = vec4(0.6,0.8,1, 0.0);
	plane[0].col2 = vec4(0.0,0.0,0.3, 0.5);

	plane[1].p = vec3(0,0, -2.5);
	plane[1].n = vec3(0.0, 0, 1.0);
	plane[1].col1 = vec4(0,0,0.3, 0.0);
	plane[1].col2 = vec4(0.0,0.3,0.0, 0.0);

	Ray r;
	r.org = org;
	r.dir = dir;
	vec4 col = vec4(0,0,0,1);
	float eps = 0.0001;
	vec4 bcol = vec4(1,1,1,1);
	for (int j = 0; j < raytraceDepth; j++)
	{
	Intersection i;
	i.hit = 0;
	i.t = 1e30;
	i.n = i.p = vec3(0);
	i.col = vec4(0);

	Intersect(r, i);
	if (i.hit != 0)
	{
	vec4 shadow = computeLightShadow(i);
	col += bcol * i.col * shadow;
	bcol = i.col / (1.0 + i.col.a i.t + shadow.a);
	}
	else
	{
	break;
	}

	r.org = vec3(i.p.x + eps * i.n.x,
	i.p.y + eps * i.n.y,
	i.p.z + eps * i.n.z);
	r.dir = reflect(r.dir, vec3(i.n.x, i.n.y, i.n.z));
	}
	col.a = 1.0;
	fragColor = col;
	}
	void Intersect(Ray r, inout Intersection i)
	{
	sphere_intersect(sphere[0], r, i);
	sphere_intersect(sphere[1], r, i);
	sphere_intersect(sphere[2], r, i);
	sphere_intersect(sphere[3], r, i);

	cube_intersect(cube[0], r, i);

	plane_intersect(plane[0], r, i);

	cubes_intersect(0.0, r, i);
	}

	void mainImage( out vec4 fragColor, in vec2 fragCoord )
	{
	vec2 mo = iMouse.xy/iResolution.xy;
	float time = 32.0 + iTime*1.5;

	// camera
	vec3 ta = vec3( 0.25, -0.75, -0.75 );
	vec3 ro = ta + vec3( 4.5cos(0.1time + 7.0mo.x), 2.2, 4.5sin(0.1time + 7.0mo.x) );
	// camera-to-world transformation
	mat3 ca = setCamera( ro, ta, 0.0 );

	vec3 tot = vec3(0.0);
	vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;

	// focal length
	const float fl = 2.5;

	// ray direction
	vec3 rd = ca * normalize( vec3(p,fl) );

	// ray differentials
	vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
	vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
	vec3 rdx = ca * normalize( vec3(px,fl) );
	vec3 rdy = ca * normalize( vec3(py,fl) );

	// render
	vec3 col = render( ro, rd, rdx, rdy );

	// gain
	// col = col*3.0/(2.5+col);

	// gamma
	col = pow( col, vec3(0.4545) );

	tot += col;
	fragColor = vec4( tot, 1.0 );
	}

	vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
	{
	// background
	vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;

	// raycast scene
	vec2 res = raycast(ro,rd);
	float t = res.x;
	float m = res.y;
	if( m>-0.5 )
	{
	vec3 pos = ro + t*rd;
	vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
	vec3 ref = reflect( rd, nor );

	// material
	col = 0.2 + 0.2sin( m2.0 + vec3(0.0,1.0,2.0) );
	float ks = 1.0;

	if( m<1.5 )
	{
	// project pixel footprint into the plane
	vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
	vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);

	float f = checkersGradBox( 3.0pos.xz, 3.0dpdx.xz, 3.0*dpdy.xz );
	col = 0.15 + f*vec3(0.05);
	ks = 0.4;
	}

	// lighting
	float occ = calcAO( pos, nor );

	vec3 lin = vec3(0.0);

	// sun
	{
	vec3 lig = normalize( vec3(-0.5, 0.4, -0.6) );
	vec3 hal = normalize( lig-rd );
	float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
	//if( dif>0.0001 )
	dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
	float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
	spe *= dif;
	spe = 0.04+0.96pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
	//spe = 0.04+0.96pow(clamp(1.0-sqrt(0.5*(1.0-dot(rd,lig))),0.0,1.0),5.0);
	lin += col2.20dif*vec3(1.30,1.00,0.70);
	lin += 5.00spevec3(1.30,1.00,0.70)*ks;
	}
	// sky
	{
	float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
	dif *= occ;
	float spe = smoothstep( -0.2, 0.2, ref.y );
	spe *= dif;
	spe = 0.04+0.96pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
	//if( spe>0.001 )
	spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
	lin += col0.60dif*vec3(0.40,0.60,1.15);
	lin += 2.00spevec3(0.40,0.60,1.30)*ks;
	}
	// back
	{
	float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
	dif *= occ;
	lin += col0.55dif*vec3(0.25,0.25,0.25);
	}
	// sss
	{
	float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
	dif *= occ;
	lin += col0.25dif*vec3(1.00,1.00,1.00);
	}

	col = lin;

	col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001tt*t ) );
	}

	return vec3( clamp(col,0.0,1.0) );
	}

	vec2 raycast( in vec3 ro, in vec3 rd )
	{
	vec2 res = vec2(-1.0,-1.0);

	float tmin = 1.0;
	float tmax = 20.0;

	// raytrace floor plane
	float tp1 = (0.0-ro.y)/rd.y;
	if( tp1>0.0 )
	{
	tmax = min( tmax, tp1 );
	res = vec2( tp1, 1.0 );
	}
	//else return res;

	// raymarch primitives
	vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
	if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
	{
	//return vec2(tb.x,2.0);
	tmin = max(tb.x,tmin);
	tmax = min(tb.y,tmax);

	float t = tmin;
	for( int i=0; i<70 && t<tmax; i++ )
	{
	vec2 h = map( ro+rd*t );
	if( abs(h.x)<(0.0001*t) )
	{
	res = vec2(t,h.y);
	break;
	}
	t += h.x;
	}
	}

	return res;
	}

	vec2 map( in vec3 pos )
	{
	vec2 res = vec2( pos.y, 0.0 );

	// bounding box
	if( sdBox( pos-vec3(-2.0,0.3,0.25),vec3(0.3,0.3,1.0) )<res.x )
	{
	res = opU( res, vec2( sdSphere( pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
	res = opU( res, vec2( sdRhombus( (pos-vec3(-2.0,0.25, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
	}

	// bounding box
	if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
	{
	res = opU( res, vec2( sdCappedTorus((pos-vec3( 0.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 25.0) );
	res = opU( res, vec2( sdBoxFrame( pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
	res = opU( res, vec2( sdCone( pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
	res = opU( res, vec2( sdCappedCone( pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
	res = opU( res, vec2( sdSolidAngle( pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
	}

	// bounding box
	if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
	{
	res = opU( res, vec2( sdTorus( (pos-vec3( 1.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 7.1 ) );
	res = opU( res, vec2( sdBox( pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
	res = opU( res, vec2( sdCapsule( pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1 ), 31.9 ) );
	res = opU( res, vec2( sdCylinder( pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
	res = opU( res, vec2( sdHexPrism( pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
	}

	// bounding box
	if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
	{
	res = opU( res, vec2( sdPyramid( pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
	res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
	res = opU( res, vec2( sdTriPrism( pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
	res = opU( res, vec2( sdEllipsoid( pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
	res = opU( res, vec2( sdHorseshoe( pos-vec3(-1.0,0.25, 1.0), vec2(cos(1.3),sin(1.3)), 0.2, 0.3, vec2(0.03,0.08) ), 11.5 ) );
	}

	// bounding box
	if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
	{
	res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
	res = opU( res, vec2( sdCylinder( pos-vec3( 2.0,0.14,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
	res = opU( res, vec2( sdCappedCone( pos-vec3( 2.0,0.09,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
	res = opU( res, vec2( sdRoundCone( pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
	res = opU( res, vec2( sdRoundCone( pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
	}

	return res;
	}

	vec2 opU( vec2 d1, vec2 d2 )
	{
	return (d1.x<d2.x) ? d1 : d2;
	}

	float sdPyramid( in vec3 p, in float h )
	{
	float m2 = h*h + 0.25;

	// symmetry
	p.xz = abs(p.xz);
	p.xz = (p.z>p.x) ? p.zx : p.xz;
	p.xz -= 0.5;

	// project into face plane (2D)
	vec3 q = vec3( p.z, hp.y - 0.5p.x, hp.x + 0.5p.y);

	float s = max(-q.x,0.0);
	float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );

	float a = m2(q.x+s)(q.x+s) + q.y*q.y;
	float b = m2(q.x+0.5t)(q.x+0.5t) + (q.y-m2t)(q.y-m2*t);

	float d2 = min(q.y,-q.xm2-q.y0.5) > 0.0 ? 0.0 : min(a,b);

	// recover 3D and scale, and add sign
	return sqrt( (d2+q.zq.z)/m2 ) sign(max(q.z,-p.y));;

	}
	// la,lb=semi axis, h=height, ra=corner
	float sdRhombus(vec3 p, float la, float lb, float h, float ra)
	{
	p = abs(p);
	vec2 b = vec2(la,lb);
	float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
	vec2 q = vec2(length(p.xz-0.5bvec2(1.0-f,1.0+f))sign(p.xb.y+p.zb.x-b.xb.y)-ra, p.y-h);
	return min(max(q.x,q.y),0.0) + length(max(q,0.0));
	}

	float sdHorseshoe( in vec3 p, in vec2 c, in float r, in float le, vec2 w )
	{
	p.x = abs(p.x);
	float l = length(p.xy);
	p.xy = mat2(-c.x, c.y,
	c.y, c.x)*p.xy;
	p.xy = vec2((p.y>0.0 \|\| p.x>0.0)?p.x:l*sign(-c.x),
	(p.x>0.0)?p.y:l );
	p.xy = vec2(p.x,abs(p.y-r))-vec2(le,0.0);

	vec2 q = vec2(length(max(p.xy,0.0)) + min(0.0,max(p.x,p.y)),p.z);
	vec2 d = abs(q) - w;
	return min(max(d.x,d.y),0.0) + length(max(d,0.0));
	}

	// materials
	vec4 mate = vec4(0.0);
	vec2 mate2 = vec2(1.0,1.0);
	if( tmat.z<0.5 )
	{
	nor = vec3(0.0,1.0,0.0);
	ref = reflect( rd, nor );
	mate.xyz = vec3(1.0);
	mate2.y = 1.0 - 0.9*(2.0/(2.0+dot(pos.xz,pos.xz)));
	}
	else if( tmat.z<1.5 )
	{
	mate2.x = 4.0;
	mate = vec4(0.16,0.32,0.0,0.8);

	float f = texturize( iChannel0, 0.15pos, nor ).x texturize( iChannel0, 0.20.25pos, nor ).x;
	mate.xyz = mix( 0.56*mate.xyz, vec3(0.21,0.28,0.0), f );

	f = texturize( iChannel0, pos, nor ).x * texturize( iChannel0, 0.25*pos, nor ).x;
	f = f*f;
	mate.xyz = mix( mate.xyz, vec3(0.21,0.28,0.0), 0.6*f );

	vec3 bnor = -1.0+2.0texturize( iChannel0, 4.0pos, nor );
	nor = normalize( nor + 0.15*bnor );
	}
	else if( tmat.z<2.5 )
	{
	vec3 q = pos-vec3(0.0,1.8,0.0) - vec3(0.0,0.44,0.35);

	float an2 = an + 0.015(-1.0+2.0noise( 6.0*iTime ));
	vec3 oq = q;
	q.x += -2.00.15clamp(sin(an2),-0.42,0.42);
	float f = length( q.xy );

	mate2.y = 1.0-smoothstep(0.24,0.35,length( oq.xy-vec2(0.0,0.035) ));
	mate = vec4(0.5,0.5,0.5,1.0);
	mate.xyz = mix( mate.xyz, vec3(0.6,0.4,0.3), 0.5*smoothstep(0.1,0.4,f) );

	vec3 c1 = vec3(0.0,0.15,0.05)(1.0-0.85f/0.19);
	float a = atan(q.y,-q.x);
	float te = fbm( 20.0vec2(0.3a,1.0*f) );
	c1 = 0.3 + 5.0te;

	c1 += vec3(0.5,1.0,0.1)0.35(0.5+te)*
	(1.0-smoothstep( 0.3,1.2,abs(a+0.5)))*
	(1.0-smoothstep( 0.0, 0.06, abs(f-0.125) ));

	mate.xyz = mix( mate.xyz, c1, 1.0-smoothstep( 0.18, 0.19, f ) );

	oq.x += -2.00.19clamp(sin(an2),-0.42,0.42);
	f = length( oq.xy );
	mate.xyz *= smoothstep( 0.07, 0.10, f );
	mate.xyz = 1.0-0.2vec3(0.5,0.9,1.0)*smoothstep( 0.2, 0.4, f );

	mate.w = 2.0;
	mate2.x = 64.0;
	}
	else if( tmat.z<3.5 )
	{
	mate = 0.8*vec4(0.85,0.7,0.6,0.0);
	mate2.x = 0.0;
	float f = smoothstep( 0.0, 0.1, 0.5*abs(pos.x)+pos.y-3.02 );
	mate.xyz = 1.0 - 0.8vec3( f );
	mate.xyz = 0.2 + 0.8smoothstep( 0.0, 1.0, texturize( iChannel0, 0.12.1pos*vec3(4.0,0.1,4.0), nor ).x );
	}
	else if( tmat.z<4.5 )
	{
	float z = smoothstep( 0.0, 2.0, pos.z+0.5 );
	mate = 0.5*vec4(0.5,0.25,0.1,0.0);
	mate.x += 0.1*(1.0-z);
	mate2.y = z;

	// this is the first time i've tried to make a short code

	#define V vec3

	float f(V p) {
	return max(0.,1.1-length(p)-.1texture(iChannel0,p.xy).r-.04sin(sin(4.p.x)+15.p.y+6.*iTime));
	}

	void mainImage(out vec4 c, vec2 p) {
	V r = iResolution,
	d = V(fract((p-.5r.xy)/r.y2.2)-.5,1),
	o = d*2.3-V(0,0,3),
	a = V(5);

	c *= 0.;
	for (int i=0; i<32; i++) {
	c.rgb += (a=mix(V(.9,1,.8),mix(mix(V(1,.9,.8),V(.8,.9,1),step(p.x,.5r.x)),V(1,.8,.9),step(p.x,r.x/4.)),step(p.x,r.x.75))-f(o+=d.05)/3.)*max(0.,(f(o)-f(o+.07)));
	}
	c = sqrt(c/(1.+c));
	}