167 lines
7.4 KiB
HLSL
167 lines
7.4 KiB
HLSL
#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
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#define DISK_SAMPLE_COUNT 64
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// Fibonacci Spiral Disk Sampling Pattern
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// https://people.irisa.fr/Ricardo.Marques/articles/2013/SF_CGF.pdf
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//
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// Normalized direction vector portion of fibonacci spiral can be baked into a LUT, regardless of sampleCount.
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// This allows us to treat the directions as a progressive sequence, using any sampleCount in range [0, n <= LUT_LENGTH]
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// the radius portion of spiral construction is coupled to sample count, but is fairly cheap to compute at runtime per sample.
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// Generated (in javascript) with:
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// var res = "";
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// for (var i = 0; i < 64; ++i)
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// {
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// var a = Math.PI * (3.0 - Math.sqrt(5.0));
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// var b = a / (2.0 * Math.PI);
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// var c = i * b;
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// var theta = (c - Math.floor(c)) * 2.0 * Math.PI;
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// res += "float2 (" + Math.cos(theta) + ", " + Math.sin(theta) + "),\n";
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// }
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static const float2 fibonacciSpiralDirection[DISK_SAMPLE_COUNT] =
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{
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float2 (1, 0),
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float2 (-0.7373688780783197, 0.6754902942615238),
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float2 (0.08742572471695988, -0.9961710408648278),
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float2 (0.6084388609788625, 0.793600751291696),
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float2 (-0.9847134853154288, -0.174181950379311),
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float2 (0.8437552948123969, -0.5367280526263233),
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float2 (-0.25960430490148884, 0.9657150743757782),
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float2 (-0.46090702471337114, -0.8874484292452536),
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float2 (0.9393212963241182, 0.3430386308741014),
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float2 (-0.924345556137805, 0.3815564084749356),
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float2 (0.423845995047909, -0.9057342725556143),
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float2 (0.29928386444487326, 0.9541641203078969),
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float2 (-0.8652112097532296, -0.501407581232427),
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float2 (0.9766757736281757, -0.21471942904125949),
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float2 (-0.5751294291397363, 0.8180624302199686),
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float2 (-0.12851068979899202, -0.9917081236973847),
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float2 (0.764648995456044, 0.6444469828838233),
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float2 (-0.9991460540072823, 0.04131782619737919),
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float2 (0.7088294143034162, -0.7053799411794157),
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float2 (-0.04619144594036213, 0.9989326054954552),
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float2 (-0.6407091449636957, -0.7677836880006569),
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float2 (0.9910694127331615, 0.1333469877603031),
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float2 (-0.8208583369658855, 0.5711318504807807),
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float2 (0.21948136924637865, -0.9756166914079191),
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float2 (0.4971808749652937, 0.8676469198750981),
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float2 (-0.952692777196691, -0.30393498034490235),
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float2 (0.9077911335843911, -0.4194225289437443),
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float2 (-0.38606108220444624, 0.9224732195609431),
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float2 (-0.338452279474802, -0.9409835569861519),
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float2 (0.8851894374032159, 0.4652307598491077),
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float2 (-0.9669700052147743, 0.25489019011123065),
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float2 (0.5408377383579945, -0.8411269468800827),
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float2 (0.16937617250387435, 0.9855514761735877),
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float2 (-0.7906231749427578, -0.6123030256690173),
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float2 (0.9965856744766464, -0.08256508601054027),
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float2 (-0.6790793464527829, 0.7340648753490806),
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float2 (0.0048782771634473775, -0.9999881011351668),
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float2 (0.6718851669348499, 0.7406553331023337),
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float2 (-0.9957327006438772, -0.09228428288961682),
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float2 (0.7965594417444921, -0.6045602168251754),
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float2 (-0.17898358311978044, 0.9838520605119474),
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float2 (-0.5326055939855515, -0.8463635632843003),
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float2 (0.9644371617105072, 0.26431224169867934),
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float2 (-0.8896863018294744, 0.4565723210368687),
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float2 (0.34761681873279826, -0.9376366819478048),
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float2 (0.3770426545691533, 0.9261958953890079),
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float2 (-0.9036558571074695, -0.4282593745796637),
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float2 (0.9556127564793071, -0.2946256262683552),
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float2 (-0.50562235513749, 0.8627549095688868),
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float2 (-0.2099523790012021, -0.9777116131824024),
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float2 (0.8152470554454873, 0.5791133210240138),
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float2 (-0.9923232342597708, 0.12367133357503751),
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float2 (0.6481694844288681, -0.7614961060013474),
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float2 (0.036443223183926, 0.9993357251114194),
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float2 (-0.7019136816142636, -0.7122620188966349),
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float2 (0.998695384655528, 0.05106396643179117),
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float2 (-0.7709001090366207, 0.6369560596205411),
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float2 (0.13818011236605823, -0.9904071165669719),
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float2 (0.5671206801804437, 0.8236347091470047),
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float2 (-0.9745343917253847, -0.22423808629319533),
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float2 (0.8700619819701214, -0.49294233692210304),
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float2 (-0.30857886328244405, 0.9511987621603146),
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float2 (-0.4149890815356195, -0.9098263912451776),
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float2 (0.9205789302157817, 0.3905565685566777)
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};
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real2 ComputeFibonacciSpiralDiskSample(const in int sampleIndex, const in real diskRadius, const in real sampleCountInverse, const in real sampleCountBias)
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{
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real sampleRadius = diskRadius * sqrt((real)sampleIndex * sampleCountInverse + sampleCountBias);
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real2 sampleDirection = fibonacciSpiralDirection[sampleIndex];
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return sampleDirection * sampleRadius;
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}
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real PenumbraSizePunctual(real Reciever, real Blocker)
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{
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return abs((Reciever - Blocker) / Blocker);
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}
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real PenumbraSizeDirectional(real Reciever, real Blocker, real rangeScale)
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{
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return abs(Reciever - Blocker) * rangeScale;
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}
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bool BlockerSearch(inout real averageBlockerDepth, inout real numBlockers, real lightArea, real3 coord, real2 sampleJitter, Texture2D shadowMap, SamplerState pointSampler, int sampleCount)
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{
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real blockerSum = 0.0;
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real sampleCountInverse = rcp((real)sampleCount);
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real sampleCountBias = 0.5 * sampleCountInverse;
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real ditherRotation = sampleJitter.x;
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for (int i = 0; i < sampleCount && i < DISK_SAMPLE_COUNT; ++i)
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{
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real2 offset = ComputeFibonacciSpiralDiskSample(i, lightArea, sampleCountInverse, sampleCountBias);
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offset = real2(offset.x * sampleJitter.y + offset.y * sampleJitter.x,
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offset.x * -sampleJitter.x + offset.y * sampleJitter.y);
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real shadowMapDepth = SAMPLE_TEXTURE2D_LOD(shadowMap, pointSampler, coord.xy + offset, 0.0).x;
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if (COMPARE_DEVICE_DEPTH_CLOSER(shadowMapDepth, coord.z))
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{
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blockerSum += shadowMapDepth;
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numBlockers += 1.0;
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}
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}
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averageBlockerDepth = blockerSum / numBlockers;
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return numBlockers >= 1;
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}
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real PCSS(real3 coord, real filterRadius, real2 scale, real2 offset, real2 sampleJitter, Texture2D shadowMap, SamplerComparisonState compSampler, int sampleCount)
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{
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real UMin = offset.x;
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real UMax = offset.x + scale.x;
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real VMin = offset.y;
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real VMax = offset.y + scale.y;
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real sum = 0.0;
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real sampleCountInverse = rcp((real)sampleCount);
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real sampleCountBias = 0.5 * sampleCountInverse;
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real ditherRotation = sampleJitter.x;
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for (int i = 0; i < sampleCount && i < DISK_SAMPLE_COUNT; ++i)
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{
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real2 offset = ComputeFibonacciSpiralDiskSample(i, filterRadius, sampleCountInverse, sampleCountBias);
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offset = real2(offset.x * sampleJitter.y + offset.y * sampleJitter.x,
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offset.x * -sampleJitter.x + offset.y * sampleJitter.y);
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real U = coord.x + offset.x;
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real V = coord.y + offset.y;
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//NOTE: We must clamp the sampling within the bounds of the shadow atlas.
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// Overfiltering will leak results from other shadow lights.
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//TODO: Investigate moving this to blocker search.
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// coord.xy = clamp(coord.xy, float2(UMin, VMin), float2(UMax, VMax));
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if (U <= UMin || U >= UMax || V <= VMin || V >= VMax)
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sum += SAMPLE_TEXTURE2D_SHADOW(shadowMap, compSampler, real3(coord.xy, coord.z)).r;
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else
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sum += SAMPLE_TEXTURE2D_SHADOW(shadowMap, compSampler, real3(U, V, coord.z)).r;
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}
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return sum / sampleCount;
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}
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