noise shader

colorful_noise_hell.glsl

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+// Taste of Noise 17 by Leon Denise 2022-05-17
+
+// A very distorted volume
+// Playing with a 3D FBM noise
+// https://www.shadertoy.com/view/fljBWK
+
+float details;
+
+// rotation matrix
+mat2 rot (float a) { return mat2(cos(a),-sin(a),sin(a),cos(a)); }
+
+// shortcut for lighting
+#define dt(rn,v,p) pow(dot(rn,normalize(v))*.5+.5,p)
+
+// https://iquilezles.org/articles/distfunctions/
+float smin(float d1, float d2, float k) { float h = clamp( 0.5 + 0.5*(d2-d1)/k, 0.0, 1.0 ); return mix( d2, d1, h ) - k*h*(1.0-h); }
+
+// transform linear value into cyclic absolute value
+vec3 bend(vec3 v)
+{
+    return abs(sin(v*6.28*2.-iTime*.5));
+}
+
+// fractal brownian motion (layers of multi scale noise)
+vec3 fbm(vec3 p)
+{
+    vec3 result = vec3(0);
+    float falloff = 0.5;
+    for (float index = 0.; index < 3.; ++index)
+    {
+        result += bend(texture(iChannel0, p/falloff).xyz) * falloff;
+        falloff /= 2.;
+    }
+    return result;
+}
+
+// signed distance function
+float map(vec3 p)
+{
+    float d = 0.;
+    
+    // FBM animated noise
+    vec3 ps = p * .5;
+    ps.z += iTime*.1;
+    vec3 spicy = fbm(ps);
+    details = spicy.x;
+    spicy = spicy * 2. - 1.;
+    
+    // displace volue
+    d += spicy.x * .8;
+    
+    // volume to surface
+    d = abs(d)-.1;
+
+    // substract volume from origin
+    float carve = -1.25+.25*sin(iTime*.1+length(p));
+    d = smin(d, -(length(p)-0.), carve);
+    
+    return d * .25;
+}
+
+// Antoine Zanuttini
+// https://www.shadertoy.com/view/3sBGzV
+vec3 getNormal (vec3 pos)
+{
+    vec2 noff = vec2(0.005,0);
+    return normalize(map(pos)-vec3(map(pos-noff.xyy), map(pos-noff.yxy), map(pos-noff.yyx)));
+}
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    // coordinates
+    vec2 uv = (fragCoord.xy - iResolution.xy / 2.)/iResolution.y;
+    vec3 noise = texture(iChannel1, fragCoord.xy/1024.+iTime).rgb;
+    vec3 ray = normalize(vec3(uv, .5));
+    vec3 pos = vec3(0,0,0);
+    
+    // init variables
+    vec3 color, normal, tint, dir, refl;
+    float index, shade, light;
+    const float count = 50.;
+
+    // ray marching
+    for (index = count; index > 0.; --index)
+    {
+        float dist = map(pos);
+        if (dist < .001) break;
+        dist *= .9+.1*noise.z;
+        pos += ray*dist;
+    }
+    
+    // lighting
+    shade = index/count;
+    normal = getNormal(pos);
+    tint = .5+.5*cos(vec3(1,2,3)+details*20.);
+    refl = reflect(ray, normal);
+    color += tint;
+    color += vec3(1.000,0.502,0.792)*dt(refl, vec3(0,0,-1), .5);
+    color = clamp(color * shade, 0., 1.);
+    
+    // temporal buffer
+    uv = fragCoord.xy / iResolution.xy;
+    vec3 frame = texture(iChannel2, uv).rgb;
+    color = mix(color, frame, .9);
+    
+    fragColor = vec4(color, 1.);
+}