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#define SSS_PASS 1 |
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#define SSS_BILATERAL 1 |
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#define SSS_DEBUG 0 |
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#define SSS_USE_TANGENT_PLANE 0 |
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#define MILLIMETERS_PER_METER 1000 |
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#ifdef SSS_MODEL_BASIC |
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#define CENTIMETERS_PER_METER 100 |
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//------------------------------------------------------------------------------------- |
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// Inputs & outputs |
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//------------------------------------------------------------------------------------- |
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float4x4 _ViewMatrix, _ProjMatrix; // TEMP: make these global |
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float _WorldScales[SSS_N_PROFILES]; // Size of the world unit in meters |
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#ifdef SSS_MODEL_DISNEY |
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float maxDistance = _FilterKernelsBasic[profileID][SSS_BASIC_N_SAMPLES - 1].a; |
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#endif |
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// Take the first (central) sample. |
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// TODO: copy its neighborhood into LDS. |
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float2 centerPosition = posInput.unPositionSS; |
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float3 centerIrradiance = LOAD_TEXTURE2D(_IrradianceSource, centerPosition).rgb; |
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float centerDepth = LOAD_TEXTURE2D(_MainDepthTexture, posInput.unPositionSS).r; |
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float centerDepth = LOAD_TEXTURE2D(_MainDepthTexture, centerPosition).r; |
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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 * abs(cornerPosVS.xy - centerPosVS.xy); |
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float2 pixelsPerMm = rcp(millimPerUnit * unitsPerPixel); |
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#if SSS_USE_TANGENT_PLANE |
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[branch] |
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if (distScale == 0) |
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{ |
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#if SSS_DEBUG |
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return float4(0, 0, 1, 1); |
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#else |
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return float4(bsdfData.diffuseColor * centerIrradiance, 1); |
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#endif |
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} |
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// Take the first (central) sample. |
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// TODO: copy its neighborhood into LDS. |
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float2 centerPosition = posInput.unPositionSS; |
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float3 centerIrradiance = LOAD_TEXTURE2D(_IrradianceSource, centerPosition).rgb; |
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UpdatePositionInput(centerDepth, _InvViewProjMatrix, _ViewProjMatrix, posInput); |
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// Compute the disk tangential to the surface. |
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float3 normalVS = mul((float3x3)_ViewMatrix, bsdfData.normalWS); |
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float3x3 basisVS = GetLocalFrame(normalVS); |
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float3 tangentX = basisVS[0] * rcp(millimPerUnit); |
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float3 tangentY = basisVS[1] * rcp(millimPerUnit); |
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// Accumulate filtered irradiance and bilateral weights (for renormalization). |
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float3 totalIrradiance, totalWeight; |
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{ |
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float centerRcpPdf = _FilterKernelsNearField[profileID][0][1]; |
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float3 centerWeight = KernelValCircle(0, shapeParam) * centerRcpPdf; |
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totalIrradiance = centerWeight * centerIrradiance; |
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totalWeight = centerWeight; |
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[unroll] |
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for (uint i = 1; i < SSS_N_SAMPLES_NEAR_FIELD; i++) |
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{ |
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float r = _FilterKernelsNearField[profileID][i][0]; |
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/* The relative sample position is known at compile time. */ |
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float phi = TWO_PI * Fibonacci2d(i, SSS_N_SAMPLES_NEAR_FIELD).y; |
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float2 vec = r * float2(cos(phi), sin(phi)); |
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float3 relPosVS = vec.x * tangentX + vec.y * tangentY; |
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float3 positionVS = centerPosVS + relPosVS; |
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float4 positionCS = mul(_ProjMatrix, float4(positionVS, 1)); |
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float2 positionSS = positionCS.xy * (rcp(positionCS.w) * 0.5) + 0.5; |
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float2 positionXY = positionSS * _ScreenSize.xy; |
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float3 irradiance = LOAD_TEXTURE2D(_IrradianceSource, positionXY).rgb; |
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/* TODO: see if making this a [branch] improves performance. */ |
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[flatten] |
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if (any(irradiance)) |
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{ |
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/* Apply bilateral weighting. */ |
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float z = LOAD_TEXTURE2D(_MainDepthTexture, positionXY).r; |
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float d = LinearEyeDepth(z, _ZBufferParams); |
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float t = d - positionVS.z; |
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float3 x = millimPerUnit * length(relPosVS + float3(0, 0, t)); |
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float p = _FilterKernelsNearField[profileID][i][1]; |
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#if SSS_BILATERAL |
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float3 w = KernelValCircle(x, shapeParam) * p; |
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#else |
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float3 w = KernelValCircle(r, shapeParam) * p; |
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#endif |
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totalIrradiance += w * irradiance; |
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totalWeight += w; |
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} |
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else |
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{ |
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/*************************************************************************/ |
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/* The irradiance is 0. This could happen for 3 reasons. */ |
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/* Most likely, the surface fragment does not have an SSS material. */ |
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/* Alternatively, our sample comes from a region without any geometry. */ |
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/* Finally, the surface fragment could be completely shadowed. */ |
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/* Our blur is energy-preserving, so 'centerWeight' should be set to 0. */ |
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/* We do not terminate the loop since we want to gather the contribution */ |
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/* of the remaining samples (e.g. in case of hair covering skin). */ |
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/* Note: See comment in the output of deferred.shader */ |
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/*************************************************************************/ |
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} |
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} |
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} |
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#else |
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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 * abs(cornerPosVS.xy - centerPosVS.xy); |
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float2 pixelsPerMm = rcp(millimPerUnit * unitsPerPixel); |
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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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millimPerUnit, pixelsPerMm, totalIrradiance, totalWeight) |
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#endif |
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} |
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#endif |
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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 * abs(cornerPosVS.xy - centerPosVS.xy); |
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float2 pixelsPerCm = rcp(centimPerUnit * unitsPerPixel); |
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// Compute the filtering direction. |
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Evgenii Golubev
7 年前