40 lines
1.1 KiB
WebGPU Shading Language
40 lines
1.1 KiB
WebGPU Shading Language
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// Noise functions from 42yeah:
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// https://blog.42yeah.is/rendering/2023/02/11/clouds.html
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fn rand(p: vec3<f32>) -> f32 {
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return fract(sin(dot(p, vec3<f32>(12.345, 67.89, 412.12))) * 42123.45) * 2.0 - 1.0;
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}
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fn value_noise(p: vec3<f32>) -> f32 {
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let u = floor(p);
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let v = fract(p);
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let s = smoothstep(vec3<f32>(0.0), vec3<f32>(1.0), v);
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let a = rand(u);
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let b = rand(u + vec3<f32>(1.0, 0.0, 0.0));
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let c = rand(u + vec3<f32>(0.0, 1.0, 0.0));
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let d = rand(u + vec3<f32>(1.0, 1.0, 0.0));
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let e = rand(u + vec3<f32>(0.0, 0.0, 1.0));
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let f = rand(u + vec3<f32>(1.0, 0.0, 1.0));
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let g = rand(u + vec3<f32>(0.0, 1.0, 1.0));
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let h = rand(u + vec3<f32>(1.0, 1.0, 1.0));
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return mix(mix(mix(a, b, s.x), mix(c, d, s.x), s.y),
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mix(mix(e, f, s.x), mix(g, h, s.x), s.y),
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s.z);
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}
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fn fbm(p: vec3<f32>) -> f32 {
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let num_octaves = 8;
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var weight = 0.5;
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var q = p;
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var ret = 0.0;
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for (var i = 0; i < num_octaves; i++)
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{
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ret += weight * value_noise(q);
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q *= 2.0;
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weight *= 0.5;
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}
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return saturate(ret);
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}
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