33 lines
1.2 KiB
GLSL
33 lines
1.2 KiB
GLSL
// MinecraftPT — Tracing Noise
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// Noise functions for ray tracing (hash-based, temporally stable).
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#ifndef TRACING_NOISE_GLSL
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#define TRACING_NOISE_GLSL
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// Per-pixel temporal noise, stable across frames
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float GetTracingNoise(vec2 screenPos, int frame, int offset){
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// Blue noise from texture + temporal interleave
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vec2 coord = (screenPos + 0.5) / screenSize;
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coord = fract(coord * vec2(128.0, 128.0) + 0.5);
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vec2 texel = coord * vec2(127.0 / 128.0) + vec2(0.5 / 128.0);
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float noise = textureLod(noisetex, texel, 0.0).r;
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return fract(noise + (frame + offset) * 0.03125);
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}
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vec2 GetTracingNoise2(vec2 screenPos, int frame, int offset){
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// 2D noise for ray directions
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vec2 coord = (screenPos + 0.5) / screenSize;
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coord = fract(coord * vec2(128.0, 128.0) + 0.5);
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vec2 texel = coord * vec2(127.0 / 128.0) + vec2(0.5 / 128.0);
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vec2 noise = textureLod(noisetex, texel, 0.0).rg;
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return fract(noise + (frame + offset) * 0.03125);
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}
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// Golden-ratio based sample rotation (for progressive sampling)
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vec2 RotateNoise(vec2 uv, int sampleIndex, int totalSamples){
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float angle = 6.28318 * float(sampleIndex) / float(totalSamples);
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mat2 rot = mat2(cos(angle), sin(angle), -sin(angle), cos(angle));
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return rot * uv;
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}
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#endif |