72 lines
1.4 KiB
HLSL
72 lines
1.4 KiB
HLSL
#ifndef _SAMPLING_PSEUDORANDOM_HLSL_
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#define _SAMPLING_PSEUDORANDOM_HLSL_
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#include "Common.hlsl"
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#include "Hashes.hlsl"
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// Xor shift PRNG
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struct QrngXorShift
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{
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uint state;
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void Init(uint2 pixelCoord, uint startSampleIndex)
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{
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state = PixelHash(pixelCoord, startSampleIndex);
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}
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void Init(uint seed, uint startSampleIndex)
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{
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state = seed;
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}
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float GetSample()
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{
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state = XorShift32(state);
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return UintToFloat01(state);
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}
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float2 GetSample(uint dimension)
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{
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return float2(GetSample(), GetSample());
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}
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void NextSample()
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{
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}
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};
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// From paper: "Hash Functions for GPU Rendering" by Jarzynski & Olano)
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struct QrngPcg4D
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{
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uint4 state;
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void Init(uint2 pixelCoord, uint startSampleIndex)
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{
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// Seed for PCG uses a sequential sample number in 4th channel, which increments on every RNG call and starts from 0
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state = uint4(pixelCoord, startSampleIndex, 0);
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}
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void Init(uint seed, uint startSampleIndex)
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{
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state = uint4(seed, 1, startSampleIndex, 0);
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}
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float GetSample()
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{
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state.w++;
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return UintToFloat01(Pcg4d(state).x);
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}
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float2 GetSample(uint dimension)
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{
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return float2(GetSample(), GetSample());
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}
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void NextSample()
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{
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state.z++;
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}
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};
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#endif // _SAMPLING_PSEUDORANDOM_HLSL_
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