57 lines
1.2 KiB
WebGPU Shading Language
57 lines
1.2 KiB
WebGPU Shading Language
override octaves: i32;
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override amplitude: f32;
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override gain: f32;
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override lacunarity: f32;
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override seedR: f32;
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override seedG: f32;
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override seedB: f32;
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override seedA: f32;
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@fragment
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fn fragment(@location(0) uv: vec2<f32>) -> @location(0) vec4<f32> {
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return vec4(
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fbm(uv, seedR),
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fbm(uv, seedG),
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fbm(uv, seedB),
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fbm(uv, seedA),
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);
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}
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fn fbm(uv: vec2<f32>, seed: f32) -> f32 {
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var st = uv;
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var v = 0.0;
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var a = amplitude;
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let shift = vec2(100.0);
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let rot = mat2x2(cos(0.5), sin(0.5),
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-sin(0.5), cos(0.50));
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for (var i = 0; i < octaves; i++) {
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v += a * noise(st, seed);
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st = rot * st * lacunarity + shift;
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a *= gain;
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}
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return v;
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}
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fn noise (st: vec2<f32>, seed: f32) -> f32 {
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let i = floor(st);
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let f = fract(st);
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let a = random(i, seed);
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let b = random(i + vec2(1.0, 0.0), seed);
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let c = random(i + vec2(0.0, 1.0), seed);
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let d = random(i + vec2(1.0, 1.0), seed);
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let u = f * f * (3.0 - 2.0 * f);
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return mix(a, b, u.x) +
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(c - a)* u.y * (1.0 - u.x) +
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(d - b) * u.x * u.y;
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}
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fn random(st: vec2<f32>, seed: f32) -> f32 {
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return fract(sin(dot(st.xy, vec2(12.9898 + seed, 78.233 + seed)))* 43758.5453123 + seed);
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}
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