17 lines
690 B
WebGPU Shading Language
17 lines
690 B
WebGPU Shading Language
/*
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contributors: Ricardo Caballero
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description: |
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Pack a float into a 4D vector. From https://github.com/mrdoob/three.js/blob/acdda10d5896aa10abdf33e971951dbf7bd8f074/src/renderers/shaders/ShaderChunk/packing.glsl
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*/
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const PackUpscale: f32 = 256. / 255.; // fraction -> 0..1 (including 1)
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const UnpackDownscale: f32 = 255. / 256.; // 0..1 -> fraction (excluding 1)
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const PackFactors = vec3f( 256. * 256. * 256., 256. * 256., 256. );
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const UnpackFactors = UnpackDownscale / vec4f( PackFactors, 1. );
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const ShiftRight8: f32 = 1. / 256.;
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fn pack(v: f32) -> vec4f {
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var r = vec4( fract( v * PackFactors ), v );
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r.yzw -= r.xyz * ShiftRight8; // tidy overflow
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return r * PackUpscale;
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}
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