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Improvements in reflection filtering
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@tippesi
tippesi committed Nov 15, 2022
1 parent 4638be9 commit ddf5c67
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Showing 3 changed files with 41 additions and 71 deletions.
6 changes: 3 additions & 3 deletions data/shader/reflection/atrous.csh
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ float ComputeEdgeStoppingWeight(float centerLuminance, float sampleLuminance,
float luminanceDiff = abs(centerLuminance - sampleLuminance);
float luminanceWeight = min(exp(-luminanceDiff / luminancePhi), 1.0);

float normalDiff = max(dot(centerNormal, sampleNormal), 0.0);
float normalDiff = saturate(dot(centerNormal, sampleNormal));
float normalWeight = min(pow(normalDiff, normalPhi), 1.0);

float depthDiff = abs(centerDepth - sampleDepth);
Expand Down Expand Up @@ -81,7 +81,7 @@ void main() {
float totalWeight = 1.0;

float variance = GetFilteredVariance(pixel);
float stdDeviation = sqrt(variance);
float stdDeviation = sqrt(max(0.0, variance));

const int radius = 2;
for (int x = -radius; x <= radius; x++) {
Expand All @@ -108,7 +108,7 @@ void main() {
centerLuminance, sampleLuminance,
centerNormal, sampleNormal,
sampleLinearDepth, centerLinearDepth,
stdDeviation, 32.0, 1.0);
stdDeviation * 10, 32.0, 1.0);

float weight = kernelWeight * edgeStoppingWeight;

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104 changes: 37 additions & 67 deletions data/shader/reflection/temporal.csh
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Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,6 @@ const ivec2 pixelOffsets[4] = ivec2[4](
ivec2(1, 1)
);

vec3 localNeighbourhood[9];

float Luma(vec3 color) {

const vec3 luma = vec3(0.299, 0.587, 0.114);
Expand All @@ -62,15 +60,6 @@ vec3 FetchTexel(ivec2 texel) {

}

void LoadData(ivec2 pixel) {

for (uint i = 0; i < 9; i++) {

localNeighbourhood[i] = FetchTexel(pixel + offsets[i]);
}

}

ivec2 FindNearest3x3(ivec2 pixel) {

ivec2 offset = ivec2(0);
Expand Down Expand Up @@ -185,12 +174,23 @@ void ComputeVarianceMinMax(out vec3 aabbMin, out vec3 aabbMax) {
vec3 m1 = vec3(0.0);
vec3 m2 = vec3(0.0);
// This could be varied using the temporal variance estimation
// By using a wide neighborhood for variance estimation (8x8) we introduce block artifacts
// These are similiar to video compression artifacts, the spatial filter mostly clears them up
const int radius = 8;
ivec2 pixel = ivec2(gl_GlobalInvocationID);
float depth = texelFetch(depthTexture, pixel, 0).r;
float linearDepth = ConvertDepthToViewSpaceDepth(depth);
for (int i = -radius; i <= radius; i++) {
for (int j = -radius; j <= radius; j++) {
vec3 color = texelFetch(currentTexture, pixel + ivec2(i, j), 0).rgb;
float historyDepth = texelFetch(depthTexture, pixel + ivec2(i, j), 0).r;
float historyLinearDepth = ConvertDepthToViewSpaceDepth(historyDepth);
float weight = min(1.0 , exp(-abs(linearDepth - historyLinearDepth)));
color *= weight;
m1 += color;
m2 += color * color;
Expand All @@ -200,7 +200,7 @@ void ComputeVarianceMinMax(out vec3 aabbMin, out vec3 aabbMax) {
float oneDividedBySampleCount = 1.0 / float((2.0 * radius + 1.0) * (2.0 * radius + 1.0));
float gamma = 1.0;
vec3 mu = m1 * oneDividedBySampleCount;
vec3 sigma = sqrt(abs((m2 * oneDividedBySampleCount) - (mu * mu)));
vec3 sigma = sqrt(max((m2 * oneDividedBySampleCount) - (mu * mu), 0.0));
aabbMin = mu - gamma * sigma;
aabbMax = mu + gamma * sigma;
Expand All @@ -209,7 +209,7 @@ void ComputeVarianceMinMax(out vec3 aabbMin, out vec3 aabbMax) {
float ComputeDisocclusionWeight(vec3 normal, vec3 historyNormal,
float historyLinearDepth, float linearDepth) {
return exp(-abs(1.0 - max(0.0, dot(normal, historyNormal))))
* exp(-abs(historyLinearDepth - linearDepth) / linearDepth);
* exp(-abs(historyLinearDepth - linearDepth) / linearDepth);
}
void main() {
Expand All @@ -219,36 +219,7 @@ void main() {
pixel.y > imageSize(resolveImage).y)
return;
LoadData(pixel);
// Find nearest pixel in localNeighbourhood to improve velocity sampling
ivec2 offset = FindNearest3x3(pixel);
vec3 tl = localNeighbourhood[0];
vec3 tc = localNeighbourhood[1];
vec3 tr = localNeighbourhood[2];
vec3 ml = localNeighbourhood[3];
vec3 mc = localNeighbourhood[4];
vec3 mr = localNeighbourhood[5];
vec3 bl = localNeighbourhood[6];
vec3 bc = localNeighbourhood[7];
vec3 br = localNeighbourhood[8];
// 3x3 box pattern
vec3 boxMin = min(tl, min(tc, min(tr, min(ml, min(mc, min(mr, min(bl, min(bc, br))))))));
vec3 boxMax = max(tl, max(tc, max(tr, max(ml, max(mc, max(mr, max(bl, max(bc, br))))))));
// 5 sample cross pattern
vec3 crossMin = min(tc, min(ml, min(mc, min(mr, bc))));
vec3 crossMax = max(tc, max(ml, max(mc, max(mr, bc))));
// Average both bounding boxes to get a more rounded shape
vec3 localNeighbourhoodMin = 0.5 * (boxMin + crossMin);
vec3 localNeighbourhoodMax = 0.5 * (boxMax + crossMax);
//ComputeVarianceMinMax(localNeighbourhoodMin, localNeighbourhoodMax);
vec3 average = 0.5 * (localNeighbourhoodMin + localNeighbourhoodMax);
vec3 localNeighbourhoodMin, localNeighbourhoodMax;
ComputeVarianceMinMax(localNeighbourhoodMin, localNeighbourhoodMax);
ivec2 velocityPixel = pixel;
Expand All @@ -261,15 +232,13 @@ void main() {
vec4 historyMoments = SampleHistoryMoments(uv);
vec3 historyColor = history.rgb;
vec3 currentColor = mc;
vec3 currentColor = texelFetch(currentTexture, pixel, 0).rgb;
vec2 currentMoments;
vec2 currentMoments;
currentMoments.r = Luma(currentColor);
currentMoments.g = currentMoments.r * currentMoments.r;
localNeighbourhoodMin = average - (average - localNeighbourhoodMin);
localNeighbourhoodMax = average + (localNeighbourhoodMax - average);
// In case of clipping we might also reject the sample. TODO: Investigate
float clipBlend = ClipBoundingBox(localNeighbourhoodMin, localNeighbourhoodMax,
historyColor, currentColor);
float adjClipBlend = saturate(clipBlend);
Expand All @@ -289,39 +258,40 @@ void main() {
|| uv.y > 1.0) ? 0.0 : factor;
vec3 normal = 2.0 * texelFetch(normalTexture, pixel, 0).rgb - 1.0;
float depth = texelFetch(depthTexture, pixel, 0).r;
float linearDepth = ConvertDepthToViewSpaceDepth(depth);
float materialConfidence = 0.0;
float normalConfidence = 0.0;
ivec2 historyPixel = ivec2(vec2(pixel) + velocity * resolution);
float maxConfidence = 0.0;
// Calculate confidence over 2x2 bilinear neighborhood
// Note that 3x3 neighborhoud could help on edges
for (int i = 0; i < 4; i++) {
ivec2 offsetPixel = historyPixel + pixelOffsets[i];
float confidence = 1.0;
uint historyMaterialIdx = texelFetch(historyMaterialIdxTexture, offsetPixel, 0).r;
// Try to find one pixel in the neighborhood which matches the material
if (historyMaterialIdx == materialIdx) {
materialConfidence = 1.0;
}
confidence *= historyMaterialIdx != materialIdx ? 0.0 : 1.0;
vec3 historyNormal = 2.0 * texelFetch(historyNormalTexture, offsetPixel, 0).rgb - 1.0;
float similarity = pow(abs(dot(historyNormal, normal)), 2.0);
if (similarity >= 0.9) {
normalConfidence = 1.0;
}
confidence *= pow(abs(dot(historyNormal, normal)), 2.0);
float historyDepth = texelFetch(depthTexture, offsetPixel, 0).r;
float historyLinearDepth = ConvertDepthToViewSpaceDepth(historyDepth);
confidence = min(1.0 , exp(-abs(linearDepth - historyLinearDepth) / linearDepth));
maxConfidence = max(maxConfidence, confidence);
}
factor *= materialConfidence * normalConfidence;
factor *= maxConfidence;
float historyLength = historyMoments.b;
if (factor == 0.0) {
historyLength = 0.0;
currentMoments.g = 1.0;
currentMoments.r = 0.0;
}
// Some stuff in the pipeline produces NaNs
if (isnan(historyColor.r) == true ||
isnan(historyColor.g) == true ||
isnan(historyColor.b) == true) {
historyLength = 0.0;
}
factor = min(factor, historyLength / (historyLength + 1.0));
vec3 resolve = mix(currentColor, historyColor, factor);
Expand All @@ -336,6 +306,6 @@ void main() {
variance = material.roughness < 0.001 ? 0.0 : variance;
imageStore(momentsImage, pixel, vec4(momentsResolve, historyLength + 1.0, 0.0));
imageStore(resolveImage, pixel, vec4(resolve, variance));
imageStore(resolveImage, pixel, vec4(vec3(resolve), variance));
}
2 changes: 1 addition & 1 deletion src/renderer/RTReflectionRenderer.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ namespace Atlas {

atrousShader.GetUniform("ipMatrix")->SetValue(camera->invProjectionMatrix);

for (int i = 0; i < 4; i++) {
for (int32_t i = 0; i < 4; i++) {
Profiler::BeginQuery("Subpass " + std::to_string(i));
atrousShader.GetUniform("stepSize")->SetValue(1 << i);

Expand Down

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