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#include "SubsurfaceScatteringSettings.cs.hlsl"
#include "CoreRP/ShaderLibrary/Packing.hlsl"
#include "CommonSubsurfaceScattering.hlsl"
// Subsurface scattering constant
#define SSS_WRAP_ANGLE (PI/12) // 15 degrees
#define SSS_WRAP_LIGHT cos(PI/2 - SSS_WRAP_ANGLE)
CBUFFER_START(UnitySSSParameters)
// Warning: Unity is not able to losslessly transfer integers larger than 2^24 to the shader system.
// Therefore, we bitcast uint to float in C#, and bitcast back to uint in the shader.
uint _EnableSSSAndTransmission; // Globally toggles subsurface and transmission scattering on/off
float _TexturingModeFlags; // 1 bit/profile; 0 = PreAndPostScatter, 1 = PostScatter
float _TransmissionFlags; // 2 bit/profile; 0 = inf. thick, 1 = thin, 2 = regular
// Old SSS Model >>>
uint _UseDisneySSS;
float4 _HalfRcpVariancesAndWeights[SSS_N_PROFILES][2]; // 2x Gaussians in RGB, A is interpolation weights
// <<< Old SSS Model
// Use float4 to avoid any packing issue between compute and pixel shaders
float4 _ThicknessRemaps[SSS_N_PROFILES]; // R: start, G = end - start, BA unused
float4 _ShapeParams[SSS_N_PROFILES]; // RGB = S = 1 / D, A = filter radius
float4 _TransmissionTintsAndFresnel0[SSS_N_PROFILES]; // RGB = 1/4 * color, A = fresnel0
float4 _WorldScales[SSS_N_PROFILES]; // X = meters per world unit; Y = world units per meter
CBUFFER_END
// ----------------------------------------------------------------------------
// helper functions
// ----------------------------------------------------------------------------
// Returns the modified albedo (diffuse color) for materials with subsurface scattering.
// Ref: Advanced Techniques for Realistic Real-Time Skin Rendering.
float3 ApplyDiffuseTexturingMode(float3 color, int subsurfaceProfile)
{
#if defined(SHADERPASS) && (SHADERPASS == SHADERPASS_SUBSURFACE_SCATTERING)
// If the SSS pass is executed, we know we have SSS enabled.
bool enableSssAndTransmission = true;
#else
bool enableSssAndTransmission = _EnableSSSAndTransmission != 0;
#endif
if (enableSssAndTransmission)
{
bool performPostScatterTexturing = IsBitSet(asuint(_TexturingModeFlags), subsurfaceProfile);
if (performPostScatterTexturing)
{
// Post-scatter texturing mode: the albedo is only applied during the SSS pass.
#if !defined(SHADERPASS) || (SHADERPASS != SHADERPASS_SUBSURFACE_SCATTERING)
color = float3(1, 1, 1);
#endif
}
else
{
// Pre- and post- scatter texturing mode.
color = sqrt(color);
}
}
return color;
}
// ----------------------------------------------------------------------------
// Encoding/decoding SSS buffer functions
// ----------------------------------------------------------------------------
struct SSSData
{
float3 diffuseColor;
float subsurfaceRadius;
int subsurfaceProfile;
};
#define SSSBufferType0 float4
// SSSBuffer texture declaration
TEXTURE2D(_SSSBufferTexture0);
void EncodeIntoSSSBuffer(SSSData sssData, uint2 positionSS, out SSSBufferType0 outSSSBuffer0)
{
outSSSBuffer0 = float4(sssData.diffuseColor, PackFloatInt8bit(sssData.subsurfaceRadius, sssData.subsurfaceProfile, 16.0));
}
void DecodeFromSSSBuffer(float4 sssBuffer, uint2 positionSS, out SSSData sssData)
{
sssData.diffuseColor = sssBuffer.rgb;
UnpackFloatInt8bit(sssBuffer.a, 16.0, sssData.subsurfaceRadius, sssData.subsurfaceProfile);
}
void DecodeFromSSSBuffer(uint2 positionSS, out SSSData sssData)
{
float4 sssBuffer = LOAD_TEXTURE2D(_SSSBufferTexture0, positionSS);
DecodeFromSSSBuffer(sssBuffer, positionSS, sssData);
}
// OUTPUT_SSSBUFFER start from SV_Target2 as SV_Target0 and SV_Target1 are used for lighting buffer
#define OUTPUT_SSSBUFFER(NAME) out GBufferType0 MERGE_NAME(NAME, 0) : SV_Target2
#define ENCODE_INTO_SSSBUFFER(SURFACE_DATA, UNPOSITIONSS, NAME) EncodeIntoSSSBuffer(ConvertSurfaceDataToSSSData(SURFACE_DATA), UNPOSITIONSS, MERGE_NAME(NAME, 0))
#define DECODE_FROM_SSSBUFFER(UNPOSITIONSS, SSS_DATA) DecodeFromSSSBuffer(UNPOSITIONSS, SSS_DATA)