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} |
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// Computes F(x)/P(x), s.t. x = sqrt(r^2 + t^2). |
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float3 ComputeBilateralWeight(float3 S, float r, float t, float rcpDistScale, float rcpPdf) |
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float3 ComputeBilateralWeight(float3 S, float r, float t, float rcpPdf) |
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// Reducing the integration distance is equivalent to stretching the integration axis. |
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float3 val = KernelValCircle(sqrt(r * r + t * t) * rcpDistScale, S); |
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float3 val = KernelValCircle(sqrt(r * r + t * t), S); |
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// Rescaling of the PDF is handled via 'totalWeight'. |
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// Rescaling of the PDF is handled by 'totalWeight'. |
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millimPerUnit, scaledPixPerMm, rcpDistScale, totalIrradiance, totalWeight) \ |
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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) \ |
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{ \ |
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float r = kernel[profileID][i][0]; \ |
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/* The relative sample position is known at compile time. */ \ |
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float2 position = centerPosUnSS + vec * scaledPixPerMm; \ |
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float2 position = centerPosUnSS + vec * pixelsPerMm; \ |
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float3 irradiance = LOAD_TEXTURE2D(_IrradianceSource, position).rgb; \ |
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\ |
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/* TODO: see if making this a [branch] improves performance. */ \ |
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float d = LinearEyeDepth(z, _ZBufferParams); \ |
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float t = millimPerUnit * d - (millimPerUnit * centerDepthVS); \ |
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float p = kernel[profileID][i][1]; \ |
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float3 w = ComputeBilateralWeight(shapeParam, r, t, rcpDistScale, p); \ |
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float3 w = ComputeBilateralWeight(shapeParam, r, t, p); \ |
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\ |
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totalIrradiance += w * irradiance; \ |
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totalWeight += w; \ |
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} |
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#define SSS_LOOP(n, kernel, profileID, shapeParam, centerPosUnSS, centerDepthVS, \ |
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millimPerUnit, scaledPixPerMm, rcpDistScale, totalIrradiance, totalWeight) \ |
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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) \ |
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{ \ |
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float centerRcpPdf = kernel[profileID][0][1]; \ |
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float3 centerWeight = KernelValCircle(0, shapeParam) * centerRcpPdf; \ |
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for (uint i = 1; i < n; i++) \ |
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{ \ |
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SSS_ITER(i, n, kernel, profileID, shapeParam, centerPosUnSS, centerDepthVS, \ |
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millimPerUnit, scaledPixPerMm, rcpDistScale, totalIrradiance, totalWeight) \ |
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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) \ |
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} \ |
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} |
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float3 cornerPosVS = ComputeViewSpacePosition(cornerPosSS, centerDepth, _InvProjMatrix); |
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// Compute the view-space dimensions of the pixel as a quad projected onto geometry. |
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float2 unitsPerPixel = 2 * (cornerPosVS.xy - centerPosVS.xy); |
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float2 unitsPerPixel = 2 * abs(cornerPosVS.xy - centerPosVS.xy); |
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float metersPerUnit = _WorldScales[profileID]; |
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float millimPerUnit = MILLIMETERS_PER_METER * metersPerUnit; |
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float2 scaledPixPerMm = distScale * rcp(millimPerUnit * unitsPerPixel); |
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// Rescaling the filter is equivalent to inversely scaling the world. |
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float metersPerUnit = _WorldScales[profileID] / distScale; |
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float millimPerUnit = MILLIMETERS_PER_METER * metersPerUnit; |
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float2 pixelsPerMm = rcp(millimPerUnit * unitsPerPixel); |
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// Take the first (central) sample. |
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// TODO: copy its neighborhood into LDS. |
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float maxDistInPixels = maxDistance * max(scaledPixPerMm.x, scaledPixPerMm.y); |
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float maxDistInPixels = maxDistance * max(pixelsPerMm.x, pixelsPerMm.y); |
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[branch] |
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if (distScale == 0 || maxDistInPixels < 1) |
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{ |
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#else |
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SSS_LOOP(SSS_N_SAMPLES_FAR_FIELD, _FilterKernelsFarField, |
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profileID, shapeParam, centerPosition, centerPosVS.z, |
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millimPerUnit, scaledPixPerMm, rcp(distScale), |
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totalIrradiance, totalWeight) |
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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) |
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#endif |
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} |
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else |
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#else |
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SSS_LOOP(SSS_N_SAMPLES_NEAR_FIELD, _FilterKernelsNearField, |
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profileID, shapeParam, centerPosition, centerPosVS.z, |
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millimPerUnit, scaledPixPerMm, rcp(distScale), |
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totalIrradiance, totalWeight) |
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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) |
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float metersPerUnit = _WorldScales[profileID] * SSS_BASIC_DISTANCE_SCALE; |
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float centimPerUnit = CENTIMETERS_PER_METER * metersPerUnit; |
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float2 scaledPixPerCm = distScale * rcp(centimPerUnit * unitsPerPixel); |
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float unitScale = centimPerUnit / distScale; |
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// Rescaling the filter is equivalent to inversely scaling the world. |
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float metersPerUnit = _WorldScales[profileID] / distScale * SSS_BASIC_DISTANCE_SCALE; |
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float centimPerUnit = CENTIMETERS_PER_METER * metersPerUnit; |
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float2 pixelsPerCm = rcp(centimPerUnit * unitsPerPixel); |
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float scaledStepSize = scaledPixPerCm.x; |
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float2 unitDirection = float2(1, 0); |
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float2 unitDirection = float2(1, 0); |
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float scaledStepSize = scaledPixPerCm.y; |
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float2 unitDirection = float2(0, 1); |
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float2 unitDirection = float2(0, 1); |
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float2 scaledDirection = scaledPixPerCm * unitDirection; |
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float2 scaledDirection = pixelsPerCm * unitDirection; |
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#if (RBG_BILATERAL_WEIGHTS != 0) |
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#if RBG_BILATERAL_WEIGHTS |
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float3 halfRcpVariance = _HalfRcpWeightedVariances[profileID].rgb; |
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#else |
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float halfRcpVariance = _HalfRcpWeightedVariances[profileID].a; |
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// We perform point sampling. Therefore, we can avoid the cost |
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// of filtering if we stay within the bounds of the current pixel. |
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// We use the value of 1 instead of 0.5 as an optimization. |
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float maxDistInPixels = scaledStepSize * maxDistance; |
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float maxDistInPixels = maxDistance * max(pixelsPerCm.x, pixelsPerCm.y); |
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[branch] |
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if (distScale == 0 || maxDistInPixels < 1) |
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[flatten] |
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if (any(sampleIrradiance)) |
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{ |
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#if SSS_BILATERAL |
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float zDistance = unitScale * sampleDepth - (unitScale * centerPosVS.z); |
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float zDistance = centimPerUnit * sampleDepth - (centimPerUnit * centerPosVS.z); |
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#endif |
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totalIrradiance += sampleWeight * sampleIrradiance; |
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totalWeight += sampleWeight; |
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