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1341 行
57 KiB
1341 行
57 KiB
//-----------------------------------------------------------------------------
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// SurfaceData and BSDFData
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//-----------------------------------------------------------------------------
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// SurfaceData is define in Lit.cs which generate Lit.cs.hlsl
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#include "Lit.cs.hlsl"
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// In case we pack data uint16 buffer we need to change the output render target format to uint16
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// TODO: Is there a way to automate these output type based on the format declare in lit.cs ?
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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#define GBufferType0 uint4
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#define GBufferType1 uint4
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// TODO: How to abstract that ? We would like to avoid this PS4 test here
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#ifdef SHADER_API_PS4
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// On PS4 we need to specify manually the format of the output render target, output type is not enough
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#pragma PSSL_target_output_format(target 0 FMT_UINT16_ABGR)
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#pragma PSSL_target_output_format(target 1 FMT_UINT16_ABGR)
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#endif
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#else
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#define GBufferType0 float4
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#define GBufferType1 float4
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#define GBufferType2 float4
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#define GBufferType3 float4
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#endif
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// Reference Lambert diffuse / GGX Specular for IBL and area lights
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#ifdef HAS_LIGHTLOOP // Both reference define below need to be define only if LightLoop is present, else we get a compile error
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// #define LIT_DISPLAY_REFERENCE_AREA
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// #define LIT_DISPLAY_REFERENCE_IBL
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#endif
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// Use Lambert diffuse instead of Disney diffuse
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// #define LIT_DIFFUSE_LAMBERT_BRDF
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// Use optimization of Precomputing LambdaV
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// TODO: Test if this is a win
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// #define LIT_USE_BSDF_PRE_LAMBDAV
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// TODO: Check if anisotropy with a dynamic if on anisotropy > 0 is performant. Because it may mean we always calculate both isotropy and anisotropy case.
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// Maybe we should always calculate anisotropy in case of standard ? Don't think the compile can optimize correctly.
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// TODO: I haven't configure this sampler in the code, we should be able to do it (but Unity don't allow it for now...)
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// By default Unity provide MIG_MAG_LINEAR_POINT sampler, so it fit with our need.
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// TODO: to avoid the message Fragment program 'Frag' : sampler 'sampler_PreIntegratedFGD' has no matching texture and will be undefined.
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// We need to test this define LIGHTLOOP_TILE_DIRECT, this is a bad workaround but no alternative until we can setup sampler correctly...
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#if defined(LIT_DISPLAY_REFERENCE_IBL) || defined(LIGHTLOOP_TILE_DIRECT)
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// When reference mode is enabled, then we need to chose another sampler not related to cubemap code...
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SAMPLER2D(sampler_LtcGGXMatrix);
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#define SRL_BilinearSampler sampler_LtcGGXMatrix // Used for all textures
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#else
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SAMPLER2D(sampler_PreIntegratedFGD);
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#define SRL_BilinearSampler sampler_PreIntegratedFGD // Used for all textures
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#endif
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// TODO: This one should be set into a constant Buffer at pass frequency (with _Screensize)
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TEXTURE2D(_PreIntegratedFGD);
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TEXTURE2D(_LtcGGXMatrix); // RGBA
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TEXTURE2D(_LtcDisneyDiffuseMatrix); // RGBA
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TEXTURE2D(_LtcMultiGGXFresnelDisneyDiffuse); // RGB, A unused
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//-----------------------------------------------------------------------------
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// Helper functions/variable specific to this material
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//-----------------------------------------------------------------------------
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float PackMaterialId(int materialId)
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{
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return float(materialId) / 3.0;
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}
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int UnpackMaterialId(float f)
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{
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return int(round(f * 3.0));
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}
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// For image based lighting, a part of the BSDF is pre-integrated.
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// This is done both for specular and diffuse (in case of DisneyDiffuse)
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void GetPreIntegratedFGD(float NdotV, float perceptualRoughness, float3 fresnel0, out float3 specularFGD, out float diffuseFGD)
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{
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// Pre-integrate GGX FGD
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// _PreIntegratedFGD.x = Gv * (1 - Fc) with Fc = (1 - H.L)^5
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// _PreIntegratedFGD.y = Gv * Fc
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// Pre integrate DisneyDiffuse FGD:
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// _PreIntegratedFGD.z = DisneyDiffuse
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float3 preFGD = SAMPLE_TEXTURE2D_LOD(_PreIntegratedFGD, SRL_BilinearSampler, float2(NdotV, perceptualRoughness), 0).xyz;
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// f0 * Gv * (1 - Fc) + Gv * Fc
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specularFGD = fresnel0 * preFGD.x + preFGD.y;
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#ifdef LIT_DIFFUSE_LAMBERT_BRDF
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diffuseFGD = 1.0;
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#else
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diffuseFGD = preFGD.z;
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#endif
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}
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//-----------------------------------------------------------------------------
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// conversion function for forward
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//-----------------------------------------------------------------------------
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BSDFData ConvertSurfaceDataToBSDFData(SurfaceData surfaceData)
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{
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BSDFData bsdfData;
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ZERO_INITIALIZE(BSDFData, bsdfData);
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bsdfData.specularOcclusion = surfaceData.specularOcclusion;
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bsdfData.normalWS = surfaceData.normalWS;
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bsdfData.perceptualRoughness = PerceptualSmoothnessToPerceptualRoughness(surfaceData.perceptualSmoothness);
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bsdfData.roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
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bsdfData.materialId = surfaceData.materialId;
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if (bsdfData.materialId == MATERIALID_LIT_STANDARD)
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{
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bsdfData.diffuseColor = surfaceData.baseColor * (1.0 - surfaceData.metallic);
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bsdfData.fresnel0 = lerp(float3(surfaceData.specular, surfaceData.specular, surfaceData.specular), surfaceData.baseColor, surfaceData.metallic);
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bsdfData.tangentWS = surfaceData.tangentWS;
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bsdfData.bitangentWS = cross(surfaceData.normalWS, surfaceData.tangentWS);
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ConvertAnisotropyToRoughness(bsdfData.roughness, surfaceData.anisotropy, bsdfData.roughnessT, bsdfData.roughnessB);
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bsdfData.anisotropy = surfaceData.anisotropy;
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bsdfData.materialId = surfaceData.anisotropy > 0 ? MATERIALID_LIT_ANISO : bsdfData.materialId;
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}
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else if (bsdfData.materialId == MATERIALID_LIT_SSS)
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{
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bsdfData.diffuseColor = surfaceData.baseColor;
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bsdfData.fresnel0 = 0.028; // TODO take from subSurfaceProfile
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bsdfData.subSurfaceRadius = surfaceData.subSurfaceRadius;
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bsdfData.thickness = surfaceData.thickness;
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bsdfData.subSurfaceProfile = surfaceData.subSurfaceProfile;
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}
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else if (bsdfData.materialId == MATERIALID_LIT_CLEAR_COAT)
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{
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bsdfData.diffuseColor = surfaceData.baseColor * (1.0 - surfaceData.metallic);
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bsdfData.fresnel0 = lerp(float3(surfaceData.specular, surfaceData.specular, surfaceData.specular), surfaceData.baseColor, surfaceData.metallic);
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bsdfData.coatNormalWS = surfaceData.coatNormalWS;
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bsdfData.coatRoughness = PerceptualSmoothnessToRoughness(surfaceData.coatPerceptualSmoothness);
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}
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else if (bsdfData.materialId == MATERIALID_LIT_SPECULAR)
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{
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bsdfData.diffuseColor = surfaceData.baseColor;
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bsdfData.fresnel0 = surfaceData.specularColor;
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}
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return bsdfData;
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}
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//-----------------------------------------------------------------------------
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// conversion function for deferred
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//-----------------------------------------------------------------------------
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// Encode SurfaceData (BSDF parameters) into GBuffer
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// Must be in sync with RT declared in HDRenderPipeline.cs ::Rebuild
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void EncodeIntoGBuffer( SurfaceData surfaceData,
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float3 bakeDiffuseLighting,
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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out GBufferType0 outGBufferU0,
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out GBufferType1 outGBufferU1
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#else
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out GBufferType0 outGBuffer0,
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out GBufferType1 outGBuffer1,
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out GBufferType2 outGBuffer2,
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out GBufferType3 outGBuffer3
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#endif
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)
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{
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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float4 outGBuffer0, outGBuffer1, outGBuffer2, outGBuffer3;
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#endif
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// RT0 - 8:8:8:8 sRGB
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outGBuffer0 = float4(surfaceData.baseColor, surfaceData.specularOcclusion);
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// RT1 - 10:10:10:2
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// Encode normal on 20bit with oct compression
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float2 octNormalWS = PackNormalOctEncode(surfaceData.normalWS);
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// We store perceptualRoughness instead of roughness because it save a sqrt ALU when decoding
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// (as we want both perceptualRoughness and roughness for the lighting due to Disney Diffuse model)
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// TODO: Store 2 bit of flag into perceptualSmoothness (one for SSR, other is free (deferred planar reflection ID ? / MatID extension ?)
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outGBuffer1 = float4(octNormalWS * 0.5 + 0.5, PerceptualSmoothnessToPerceptualRoughness(surfaceData.perceptualSmoothness), PackMaterialId(surfaceData.materialId));
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// RT2 - 8:8:8:8
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if (surfaceData.materialId == MATERIALID_LIT_STANDARD)
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{
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// Encode tangent on 16bit with oct compression
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float2 octTangentWS = PackNormalOctEncode(surfaceData.tangentWS);
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// TODO: store metal and specular together, specular should be an enum (fixed value)
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outGBuffer2 = float4(octTangentWS * 0.5 + 0.5, surfaceData.anisotropy, surfaceData.metallic);
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}
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else if (surfaceData.materialId == MATERIALID_LIT_SSS)
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{
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outGBuffer2 = float4(surfaceData.subSurfaceRadius, surfaceData.thickness, 0.0, surfaceData.subSurfaceProfile / 8.0f); // Number of profile not define yet
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}
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else if (surfaceData.materialId == MATERIALID_LIT_CLEAR_COAT)
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{
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// Encode coat normal on 16bit with oct compression
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float2 octCoatNormalWS = PackNormalOctEncode(surfaceData.coatNormalWS);
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// TODO: store metal and specular together, specular should be an enum (fixed value)
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outGBuffer2 = float4(octCoatNormalWS * 0.5 + 0.5, PerceptualSmoothnessToRoughness(surfaceData.coatPerceptualSmoothness), surfaceData.metallic);
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}
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else if (surfaceData.materialId == MATERIALID_LIT_SPECULAR)
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{
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outGBuffer2 = float4(surfaceData.specularColor, 0.0);
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}
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// Lighting
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outGBuffer3 = float4(bakeDiffuseLighting, 0.0);
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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// Now pack all buffer into 2 uint buffer
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// We don't have hardware sRGB to store base color in case we pack int u16, so rather than perform full sRGB encoding just use cheap gamma20
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// TODO: test alternative like FastLinearToSRGB to better match unpacked gbuffer
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outGBuffer0.xyz = LinearToGamma20(outGBuffer0.xyz);
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uint packedGBuffer1 = PackR10G10B10A2(outGBuffer1);
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outGBufferU0 = uint4( PackFloatToUInt(outGBuffer0.x, 8, 0) | PackFloatToUInt(outGBuffer0.y, 8, 8),
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PackFloatToUInt(outGBuffer0.z, 8, 0) | PackFloatToUInt(outGBuffer0.w, 8, 8),
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(packedGBuffer1 & 0x0000FFFF),
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(packedGBuffer1 & 0xFFFF0000) >> 16);
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uint packedGBuffer3 = PackR11G11B10f(outGBuffer3.xyz);
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outGBufferU1 = uint4( PackFloatToUInt(outGBuffer2.x, 8, 0) | PackFloatToUInt(outGBuffer2.y, 8, 8),
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PackFloatToUInt(outGBuffer2.z, 8, 0) | PackFloatToUInt(outGBuffer2.w, 8, 8),
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(packedGBuffer3 & 0x0000FFFF),
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(packedGBuffer3 & 0xFFFF0000) >> 16);
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#endif
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}
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void DecodeFromGBuffer(
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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GBufferType0 inGBufferU0,
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GBufferType1 inGBufferU1,
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#else
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GBufferType0 inGBuffer0,
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GBufferType1 inGBuffer1,
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GBufferType2 inGBuffer2,
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GBufferType3 inGBuffer3,
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#endif
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out BSDFData bsdfData,
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out float3 bakeDiffuseLighting)
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{
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ZERO_INITIALIZE(BSDFData, bsdfData);
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#if SHADEROPTIONS_PACK_GBUFFER_IN_U16
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float4 inGBuffer0, inGBuffer1, inGBuffer2, inGBuffer3;
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inGBuffer0.x = UnpackUIntToFloat(inGBufferU0.x, 8, 0);
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inGBuffer0.y = UnpackUIntToFloat(inGBufferU0.x, 8, 8);
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inGBuffer0.z = UnpackUIntToFloat(inGBufferU0.y, 8, 0);
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inGBuffer0.w = UnpackUIntToFloat(inGBufferU0.y, 8, 8);
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inGBuffer0.xyz = Gamma20ToLinear(inGBuffer0.xyz);
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uint packedGBuffer1 = inGBufferU0.z | inGBufferU0.w << 16;
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inGBuffer1 = UnpackR10G10B10A2(packedGBuffer1);
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inGBuffer2.x = UnpackUIntToFloat(inGBufferU1.x, 8, 0);
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inGBuffer2.y = UnpackUIntToFloat(inGBufferU1.x, 8, 8);
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inGBuffer2.z = UnpackUIntToFloat(inGBufferU1.y, 8, 0);
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inGBuffer2.w = UnpackUIntToFloat(inGBufferU1.y, 8, 8);
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uint packedGBuffer3 = inGBufferU1.z | inGBufferU1.w << 16;
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inGBuffer3.xyz = UnpackR11G11B10f(packedGBuffer1);
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inGBuffer3.w = 0.0;
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#endif
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float3 baseColor = inGBuffer0.rgb;
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bsdfData.specularOcclusion = inGBuffer0.a;
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bsdfData.normalWS = UnpackNormalOctEncode(float2(inGBuffer1.r * 2.0 - 1.0, inGBuffer1.g * 2.0 - 1.0));
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bsdfData.perceptualRoughness = inGBuffer1.b;
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bsdfData.roughness = PerceptualRoughnessToRoughness(bsdfData.perceptualRoughness);
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bsdfData.materialId = UnpackMaterialId(inGBuffer1.a);
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if (bsdfData.materialId == MATERIALID_LIT_STANDARD)
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{
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float metallic = inGBuffer2.a;
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// TODO extract spec
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float specular = 0.04;
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float anisotropy = inGBuffer2.b;
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bsdfData.diffuseColor = baseColor * (1.0 - metallic);
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bsdfData.fresnel0 = lerp(float3(specular, specular, specular), baseColor, metallic);
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bsdfData.tangentWS = UnpackNormalOctEncode(float2(inGBuffer2.rg * 2.0 - 1.0));
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// TODO: Do we need to orthonormalize here, IIRC Eric say that we should
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bsdfData.bitangentWS = cross(bsdfData.normalWS, bsdfData.tangentWS);
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ConvertAnisotropyToRoughness(bsdfData.roughness, anisotropy, bsdfData.roughnessT, bsdfData.roughnessB);
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bsdfData.anisotropy = anisotropy;
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bsdfData.materialId = anisotropy > 0 ? MATERIALID_LIT_ANISO : bsdfData.materialId;
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}
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else if (bsdfData.materialId == MATERIALID_LIT_SSS)
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{
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bsdfData.diffuseColor = baseColor;
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bsdfData.fresnel0 = 0.028; // TODO take from subSurfaceProfile
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bsdfData.subSurfaceRadius = inGBuffer2.r;
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bsdfData.thickness = inGBuffer2.g;
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bsdfData.subSurfaceProfile = inGBuffer2.a * 8.0f;
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}
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else if (bsdfData.materialId == MATERIALID_LIT_CLEAR_COAT)
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{
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float metallic = inGBuffer2.a;
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// TODO extract spec
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float specular = 0.04;
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bsdfData.diffuseColor = baseColor * (1.0 - metallic);
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bsdfData.fresnel0 = lerp(float3(specular, specular, specular), baseColor, metallic);
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bsdfData.coatNormalWS = UnpackNormalOctEncode(float2(inGBuffer2.rg * 2.0 - 1.0));
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bsdfData.coatRoughness = inGBuffer2.b;
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}
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else if (bsdfData.materialId == MATERIALID_LIT_SPECULAR)
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{
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bsdfData.diffuseColor = baseColor;
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bsdfData.fresnel0 = inGBuffer2.rgb;
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}
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bakeDiffuseLighting = inGBuffer3.rgb;
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}
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//-----------------------------------------------------------------------------
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// Debug method (use to display values)
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//-----------------------------------------------------------------------------
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void GetSurfaceDataDebug(uint paramId, SurfaceData surfaceData, inout float3 result, inout bool needLinearToSRGB)
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{
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switch (paramId)
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{
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case DEBUGVIEW_LIT_SURFACEDATA_BASE_COLOR:
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result = surfaceData.baseColor; needLinearToSRGB = true;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_SPECULAR_OCCLUSION:
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result = surfaceData.specularOcclusion.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_NORMAL_WS:
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result = surfaceData.normalWS * 0.5 + 0.5;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_PERCEPTUAL_SMOOTHNESS:
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result = surfaceData.perceptualSmoothness.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_MATERIAL_ID:
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result = GetIndexColor(surfaceData.materialId);
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_AMBIENT_OCCLUSION:
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result = surfaceData.ambientOcclusion.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_TANGENT_WS:
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result = surfaceData.tangentWS * 0.5 + 0.5;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_ANISOTROPY:
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result = surfaceData.anisotropy.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_METALLIC:
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result = surfaceData.metallic.xxx;
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break;
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// TODO: Remap here!
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case DEBUGVIEW_LIT_SURFACEDATA_SPECULAR:
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result = surfaceData.specular.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_SUB_SURFACE_RADIUS:
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result = surfaceData.subSurfaceRadius.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_THICKNESS:
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result = surfaceData.thickness.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_SUB_SURFACE_PROFILE:
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result = GetIndexColor(surfaceData.subSurfaceProfile);
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_COAT_NORMAL_WS:
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result = surfaceData.coatNormalWS * 0.5 + 0.5;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_COAT_PERCEPTUAL_SMOOTHNESS:
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result = surfaceData.coatPerceptualSmoothness.xxx;
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break;
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case DEBUGVIEW_LIT_SURFACEDATA_SPECULAR_COLOR:
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result = surfaceData.specularColor; needLinearToSRGB = true;
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break;
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}
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}
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void GetBSDFDataDebug(uint paramId, BSDFData bsdfData, inout float3 result, inout bool needLinearToSRGB)
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{
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switch (paramId)
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{
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case DEBUGVIEW_LIT_BSDFDATA_DIFFUSE_COLOR:
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result = bsdfData.diffuseColor; needLinearToSRGB = true;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_FRESNEL0:
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result = bsdfData.fresnel0;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_SPECULAR_OCCLUSION:
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result = bsdfData.specularOcclusion.xxx;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_NORMAL_WS:
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result = bsdfData.normalWS * 0.5 + 0.5;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_PERCEPTUAL_ROUGHNESS:
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result = bsdfData.perceptualRoughness.xxx;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS:
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result = bsdfData.roughness.xxx;
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break;
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case DEBUGVIEW_LIT_BSDFDATA_MATERIAL_ID:
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result = GetIndexColor(bsdfData.materialId);
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_TANGENT_WS:
|
|
result = bsdfData.tangentWS * 0.5 + 0.5;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_BITANGENT_WS:
|
|
result = bsdfData.bitangentWS * 0.5 + 0.5;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_T:
|
|
result = bsdfData.roughnessT.xxx;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_ROUGHNESS_B:
|
|
result = bsdfData.roughnessB.xxx;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_ANISOTROPY:
|
|
result = bsdfData.anisotropy.xxx;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_SUB_SURFACE_RADIUS:
|
|
result = bsdfData.subSurfaceRadius.xxx;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_THICKNESS:
|
|
result = bsdfData.thickness.xxx;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_SUB_SURFACE_PROFILE:
|
|
result = GetIndexColor(bsdfData.subSurfaceProfile);
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_COAT_NORMAL_WS:
|
|
result = bsdfData.coatNormalWS * 0.5 + 0.5;
|
|
break;
|
|
case DEBUGVIEW_LIT_BSDFDATA_COAT_ROUGHNESS:
|
|
result = bsdfData.coatRoughness.xxx;
|
|
break;
|
|
}
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// PreLightData
|
|
//-----------------------------------------------------------------------------
|
|
|
|
// Precomputed lighting data to send to the various lighting functions
|
|
struct PreLightData
|
|
{
|
|
float NdotV;
|
|
float ggxLambdaV;
|
|
|
|
// Aniso
|
|
float TdotV;
|
|
float BdotV;
|
|
|
|
float anisoGGXLambdaV;
|
|
|
|
float3 iblDirWS; // Dominant specular direction, used for IBL in EvaluateBSDF_Env()
|
|
|
|
float3 specularFGD; // Store preconvole BRDF for both specular and diffuse
|
|
float diffuseFGD;
|
|
|
|
// area light
|
|
float3x3 ltcXformGGX; // TODO: make sure the compiler not wasting VGPRs on constants
|
|
float3x3 ltcXformDisneyDiffuse; // TODO: make sure the compiler not wasting VGPRs on constants
|
|
float ltcGGXFresnelMagnitudeDiff; // The difference of magnitudes of GGX and Fresnel
|
|
float ltcGGXFresnelMagnitude;
|
|
float ltcDisneyDiffuseMagnitude;
|
|
};
|
|
|
|
PreLightData GetPreLightData(float3 V, PositionInputs posInput, BSDFData bsdfData)
|
|
{
|
|
PreLightData preLightData;
|
|
|
|
// TODO: check Eric idea about doing that when writting into the GBuffer (with our forward decal)
|
|
preLightData.NdotV = GetShiftedNdotV(bsdfData.normalWS, V, false);
|
|
|
|
preLightData.ggxLambdaV = GetSmithJointGGXLambdaV(preLightData.NdotV, bsdfData.roughness);
|
|
|
|
float iblNdotV = preLightData.NdotV;
|
|
float3 iblNormalWS = bsdfData.normalWS;
|
|
|
|
// Check if we precompute anisotropy too
|
|
if (bsdfData.materialId == MATERIALID_LIT_ANISO)
|
|
{
|
|
preLightData.TdotV = dot(bsdfData.tangentWS, V);
|
|
preLightData.BdotV = dot(bsdfData.bitangentWS, V);
|
|
preLightData.anisoGGXLambdaV = GetSmithJointGGXAnisoLambdaV(preLightData.TdotV, preLightData.BdotV, preLightData.NdotV, bsdfData.roughnessT, bsdfData.roughnessB);
|
|
// Tangent = highlight stretch (anisotropy) direction. Bitangent = grain (brush) direction.
|
|
iblNormalWS = GetAnisotropicModifiedNormal(bsdfData.bitangentWS, bsdfData.normalWS, V, bsdfData.anisotropy);
|
|
|
|
// NOTE: If we follow the theory we should use the modified normal for the different calculation implying a normal (like NDotV) and use iblNormalWS
|
|
// into function like GetSpecularDominantDir(). However modified normal is just a hack. The goal is just to stretch a cubemap, no accuracy here.
|
|
// With this in mind and for performance reasons we chose to only use modified normal to calculate R.
|
|
// iblNdotV = GetShiftedNdotV(iblNormalWS, V), false);
|
|
}
|
|
|
|
GetPreIntegratedFGD(iblNdotV, bsdfData.perceptualRoughness, bsdfData.fresnel0, preLightData.specularFGD, preLightData.diffuseFGD);
|
|
|
|
// We need to take into account the modified normal for faking anisotropic here.
|
|
float3 iblR = reflect(-V, iblNormalWS);
|
|
preLightData.iblDirWS = GetSpecularDominantDir(bsdfData.normalWS, iblR, bsdfData.roughness);
|
|
|
|
// Area light specific
|
|
// UVs for sampling the LUTs
|
|
float theta = FastACos(dot(bsdfData.normalWS, V));
|
|
// Scale and bias for the current precomputed table - the constant use here are the one that have been use when the table in LtcData.DisneyDiffuse.cs and LtcData.GGX.cs was use
|
|
float2 uv = 0.0078125 + 0.984375 * float2(bsdfData.perceptualRoughness, theta * INV_HALF_PI);
|
|
|
|
// Get the inverse LTC matrix for GGX
|
|
// Note we load the matrix transpose (avoid to have to transpose it in shader)
|
|
preLightData.ltcXformGGX = 0.0;
|
|
preLightData.ltcXformGGX._m22 = 1.0;
|
|
preLightData.ltcXformGGX._m00_m02_m11_m20 = SAMPLE_TEXTURE2D_LOD(_LtcGGXMatrix, SRL_BilinearSampler, uv, 0);
|
|
|
|
// Get the inverse LTC matrix for Disney Diffuse
|
|
// Note we load the matrix transpose (avoid to have to transpose it in shader)
|
|
preLightData.ltcXformDisneyDiffuse = 0.0;
|
|
preLightData.ltcXformDisneyDiffuse._m22 = 1.0;
|
|
preLightData.ltcXformDisneyDiffuse._m00_m02_m11_m20 = SAMPLE_TEXTURE2D_LOD(_LtcDisneyDiffuseMatrix, SRL_BilinearSampler, uv, 0);
|
|
|
|
float3 ltcMagnitude = SAMPLE_TEXTURE2D_LOD(_LtcMultiGGXFresnelDisneyDiffuse, SRL_BilinearSampler, uv, 0).r;
|
|
preLightData.ltcGGXFresnelMagnitudeDiff = ltcMagnitude.r;
|
|
preLightData.ltcGGXFresnelMagnitude = ltcMagnitude.g;
|
|
preLightData.ltcDisneyDiffuseMagnitude = ltcMagnitude.b;
|
|
|
|
return preLightData;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// bake lighting function
|
|
//-----------------------------------------------------------------------------
|
|
|
|
// GetBakedDiffuseLigthing function compute the bake lighting + emissive color to be store in emissive buffer (Deferred case)
|
|
// In forward it must be add to the final contribution.
|
|
// This function require the 3 structure surfaceData, builtinData, bsdfData because it may require both the engine side data, and data that will not be store inside the gbuffer.
|
|
float3 GetBakedDiffuseLigthing(SurfaceData surfaceData, BuiltinData builtinData, BSDFData bsdfData, PreLightData preLightData)
|
|
{
|
|
// Premultiply bake diffuse lighting information with DisneyDiffuse pre-integration
|
|
return builtinData.bakeDiffuseLighting * preLightData.diffuseFGD * surfaceData.ambientOcclusion * bsdfData.diffuseColor + builtinData.emissiveColor;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// light transport functions
|
|
//-----------------------------------------------------------------------------
|
|
|
|
LighTransportData GetLightTransportData(SurfaceData surfaceData, BuiltinData builtinData, BSDFData bsdfData)
|
|
{
|
|
LighTransportData lightTransportData;
|
|
|
|
// diffuseColor for lightmapping should basically be diffuse color.
|
|
// But rough metals (black diffuse) still scatter quite a lot of light around, so
|
|
// we want to take some of that into account too.
|
|
|
|
lightTransportData.diffuseColor = bsdfData.diffuseColor + bsdfData.fresnel0 * bsdfData.roughness * 0.5 * surfaceData.metallic;
|
|
lightTransportData.emissiveColor = builtinData.emissiveColor;
|
|
|
|
return lightTransportData;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// LightLoop related function (Only include if required)
|
|
// HAS_LIGHTLOOP is define in Lighting.hlsl
|
|
//-----------------------------------------------------------------------------
|
|
|
|
#ifdef HAS_LIGHTLOOP
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// BSDF share between directional light, punctual light and area light (reference)
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void BSDF( float3 V, float3 L, float3 positionWS, PreLightData preLightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting,
|
|
out float3 specularLighting)
|
|
{
|
|
float3 H = normalize(V + L);
|
|
float LdotH = saturate(dot(L, H));
|
|
float NdotH = saturate(dot(bsdfData.normalWS, H));
|
|
float NdotL = saturate(dot(bsdfData.normalWS, L));
|
|
float3 F = F_Schlick(bsdfData.fresnel0, LdotH);
|
|
|
|
float Vis;
|
|
float D;
|
|
// TODO: this way of handling aniso may not be efficient, or maybe with material classification, need to check perf here
|
|
// Maybe always using aniso maybe a win ?
|
|
if (bsdfData.materialId == MATERIALID_LIT_ANISO)
|
|
{
|
|
float TdotL = saturate(dot(bsdfData.tangentWS, L));
|
|
float BdotL = saturate(dot(bsdfData.bitangentWS, L));
|
|
|
|
#ifdef LIT_USE_BSDF_PRE_LAMBDAV
|
|
Vis = V_SmithJointGGXAnisoLambdaV( preLightData.TdotV, preLightData.BdotV, preLightData.NdotV, TdotL, BdotL, NdotL,
|
|
bsdfData.roughnessT, bsdfData.roughnessB, preLightData.anisoGGXLambdaV);
|
|
#else
|
|
// TODO: Do comparison between this correct version and the one from isotropic and see if there is any visual difference
|
|
Vis = V_SmithJointGGXAniso( preLightData.TdotV, preLightData.BdotV, preLightData.NdotV, TdotL, BdotL, NdotL,
|
|
bsdfData.roughnessT, bsdfData.roughnessB);
|
|
#endif
|
|
|
|
// For anisotropy we must not saturate these values
|
|
float TdotH = dot(bsdfData.tangentWS, H);
|
|
float BdotH = dot(bsdfData.bitangentWS, H);
|
|
D = D_GGXAniso(TdotH, BdotH, NdotH, bsdfData.roughnessT, bsdfData.roughnessB);
|
|
}
|
|
else
|
|
{
|
|
#ifdef LIT_USE_BSDF_PRE_LAMBDAV
|
|
Vis = V_SmithJointGGX(NdotL, preLightData.NdotV, bsdfData.roughness, preLightData.ggxLambdaV);
|
|
#else
|
|
Vis = V_SmithJointGGX(NdotL, preLightData.NdotV, bsdfData.roughness);
|
|
#endif
|
|
D = D_GGX(NdotH, bsdfData.roughness);
|
|
}
|
|
specularLighting = F * (Vis * D);
|
|
#ifdef LIT_DIFFUSE_LAMBERT_BRDF
|
|
float diffuseTerm = Lambert();
|
|
#else
|
|
float diffuseTerm = DisneyDiffuse(preLightData.NdotV, NdotL, LdotH, bsdfData.perceptualRoughness);
|
|
#endif
|
|
diffuseLighting = bsdfData.diffuseColor * diffuseTerm;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Directional
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void EvaluateBSDF_Directional( LightLoopContext lightLoopContext,
|
|
float3 V, PositionInputs posInput, PreLightData preLightData, DirectionalLightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting,
|
|
out float3 specularLighting)
|
|
{
|
|
float3 positionWS = posInput.positionWS;
|
|
|
|
float3 L = -lightData.forward; // Lights are pointing backward in Unity
|
|
float illuminance = saturate(dot(bsdfData.normalWS, L));
|
|
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
float3 cookieColor = float3(1.0, 1.0, 1.0);
|
|
|
|
[branch] if (lightData.shadowIndex >= 0 && illuminance > 0.0f)
|
|
{
|
|
float shadowAttenuation = GetDirectionalShadowAttenuation(lightLoopContext, positionWS, lightData.shadowIndex, L, posInput.unPositionSS);
|
|
|
|
illuminance *= shadowAttenuation;
|
|
}
|
|
|
|
[branch] if (lightData.cookieIndex >= 0 && illuminance > 0.0)
|
|
{
|
|
float3 unL = positionWS - lightData.positionWS;
|
|
|
|
// Project 'unL' onto the light's axes.
|
|
float2 coord = float2(dot(unL, lightData.right), dot(unL, lightData.up));
|
|
|
|
// Rescale the texture.
|
|
coord.x *= lightData.invScaleX;
|
|
coord.y *= lightData.invScaleY;
|
|
|
|
// Remap the texture coordinates from [-1, 1]^2 to [0, 1]^2.
|
|
coord = coord * 0.5 + 0.5;
|
|
|
|
// Tile the texture if the 'repeat' wrap mode is enabled.
|
|
if (lightData.tileCookie)
|
|
coord = frac(coord);
|
|
|
|
float4 cookie = SampleCookie2D(lightLoopContext, coord, lightData.cookieIndex);
|
|
|
|
cookieColor = cookie.rgb;
|
|
illuminance *= cookie.a;
|
|
}
|
|
|
|
[branch] if (illuminance > 0.0f)
|
|
{
|
|
BSDF(V, L, positionWS, preLightData, bsdfData, diffuseLighting, specularLighting);
|
|
diffuseLighting *= (cookieColor * lightData.color) * (illuminance * lightData.diffuseScale);
|
|
specularLighting *= (cookieColor * lightData.color) * (illuminance * lightData.specularScale);
|
|
}
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Punctual
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void EvaluateBSDF_Punctual( LightLoopContext lightLoopContext,
|
|
float3 V, PositionInputs posInput, PreLightData preLightData, LightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting,
|
|
out float3 specularLighting)
|
|
{
|
|
float3 positionWS = posInput.positionWS;
|
|
|
|
// All punctual light type in the same formula, attenuation is neutral depends on light type.
|
|
// light.positionWS is the normalize light direction in case of directional light and invSqrAttenuationRadius is 0
|
|
// mean dot(unL, unL) = 1 and mean GetDistanceAttenuation() will return 1
|
|
// For point light and directional GetAngleAttenuation() return 1
|
|
|
|
float3 unL = lightData.positionWS - positionWS;
|
|
float3 L = normalize(unL);
|
|
|
|
float attenuation = GetDistanceAttenuation(unL, lightData.invSqrAttenuationRadius);
|
|
// Reminder: lights are ortiented backward (-Z)
|
|
attenuation *= GetAngleAttenuation(L, -lightData.forward, lightData.angleScale, lightData.angleOffset);
|
|
float illuminance = saturate(dot(bsdfData.normalWS, L)) * attenuation;
|
|
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
float3 cookieColor = float3(1.0, 1.0, 1.0);
|
|
|
|
// TODO: measure impact of having all these dynamic branch here and the gain (or not) of testing illuminace > 0
|
|
|
|
[branch] if (lightData.IESIndex >= 0 && illuminance > 0.0)
|
|
{
|
|
float3x3 lightToWorld = float3x3(lightData.right, lightData.up, lightData.forward);
|
|
float2 sphericalCoord = GetIESTextureCoordinate(lightToWorld, L);
|
|
illuminance *= SampleIES(lightLoopContext, lightData.IESIndex, sphericalCoord, 0).r;
|
|
}
|
|
|
|
[branch] if (lightData.shadowIndex >= 0 && illuminance > 0.0)
|
|
{
|
|
float3 offset = float3(0.0, 0.0, 0.0); // GetShadowPosOffset(nDotL, normal);
|
|
float shadowAttenuation = GetPunctualShadowAttenuation(lightLoopContext, lightData.lightType, positionWS + offset, lightData.shadowIndex, L, posInput.unPositionSS);
|
|
shadowAttenuation = lerp(1.0, shadowAttenuation, lightData.shadowDimmer);
|
|
|
|
illuminance *= shadowAttenuation;
|
|
}
|
|
|
|
[branch] if (lightData.cookieIndex >= 0 && illuminance > 0.0)
|
|
{
|
|
float3x3 lightToWorld = float3x3(lightData.right, lightData.up, lightData.forward);
|
|
|
|
// Rotate 'L' into the light space.
|
|
// We perform the negation because lights are oriented backwards (-Z).
|
|
float3 coord = mul(-L, transpose(lightToWorld));
|
|
|
|
float4 cookie;
|
|
|
|
[branch] if (lightData.lightType == GPULIGHTTYPE_SPOT)
|
|
{
|
|
// Perform the perspective projection of the hemisphere onto the disk.
|
|
coord.xy /= coord.z;
|
|
|
|
// Rescale the projective coordinates to fit into the [-1, 1]^2 range.
|
|
float cotOuterHalfAngle = lightData.size.x;
|
|
coord.xy *= cotOuterHalfAngle;
|
|
|
|
// Remap the texture coordinates from [-1, 1]^2 to [0, 1]^2.
|
|
coord.xy = coord.xy * 0.5 + 0.5;
|
|
|
|
cookie = SampleCookie2D(lightLoopContext, coord.xy, lightData.cookieIndex);
|
|
}
|
|
else // GPULIGHTTYPE_POINT
|
|
{
|
|
cookie = SampleCookieCube(lightLoopContext, coord, lightData.cookieIndex);
|
|
}
|
|
|
|
cookieColor = cookie.rgb;
|
|
illuminance *= cookie.a;
|
|
}
|
|
|
|
[branch] if (illuminance > 0.0)
|
|
{
|
|
BSDF(V, L, positionWS, preLightData, bsdfData, diffuseLighting, specularLighting);
|
|
|
|
diffuseLighting *= (cookieColor * lightData.color) * (illuminance * lightData.diffuseScale);
|
|
specularLighting *= (cookieColor * lightData.color) * (illuminance * lightData.specularScale);
|
|
}
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Line - Reference
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void IntegrateBSDF_LineRef(float3 V, float3 positionWS,
|
|
PreLightData preLightData, LightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting, out float3 specularLighting,
|
|
int sampleCount = 128)
|
|
{
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
const float len = lightData.size.x;
|
|
const float3 T = lightData.right;
|
|
const float3 P1 = lightData.positionWS - T * (0.5 * len);
|
|
const float dt = len * rcp(sampleCount);
|
|
const float off = 0.5 * dt;
|
|
|
|
// Uniformly sample the line segment with the Pdf = 1 / len.
|
|
const float invPdf = len;
|
|
|
|
for (int i = 0; i < sampleCount; ++i)
|
|
{
|
|
// Place the sample in the middle of the interval.
|
|
float t = off + i * dt;
|
|
float3 sPos = P1 + t * T;
|
|
float3 unL = sPos - positionWS;
|
|
float dist2 = dot(unL, unL);
|
|
float3 L = normalize(unL);
|
|
float sinLT = length(cross(L, T));
|
|
float NdotL = saturate(dot(bsdfData.normalWS, L));
|
|
|
|
float3 lightDiff, lightSpec;
|
|
|
|
BSDF(V, L, positionWS, preLightData, bsdfData, lightDiff, lightSpec);
|
|
|
|
// The value of the specular BSDF could be infinite.
|
|
// Summing up infinities leads to NaNs.
|
|
lightSpec = min(lightSpec, FLT_MAX);
|
|
|
|
diffuseLighting += lightDiff * (sinLT / dist2 * NdotL);
|
|
specularLighting += lightSpec * (sinLT / dist2 * NdotL);
|
|
}
|
|
|
|
// The factor of 2 is due to the fact: Integral{0, 2 PI}{max(0, cos(x))dx} = 2.
|
|
float normFactor = 2.0 * invPdf * rcp(sampleCount);
|
|
|
|
diffuseLighting *= normFactor * lightData.diffuseScale * lightData.color;
|
|
specularLighting *= normFactor * lightData.specularScale * lightData.color;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Line - Approximation with Linearly Transformed Cosines
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void EvaluateBSDF_Line(LightLoopContext lightLoopContext,
|
|
float3 V, PositionInputs posInput,
|
|
PreLightData preLightData, LightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting, out float3 specularLighting)
|
|
{
|
|
float3 positionWS = posInput.positionWS;
|
|
|
|
#ifdef LIT_DISPLAY_REFERENCE_AREA
|
|
IntegrateBSDF_LineRef(V, positionWS, preLightData, lightData, bsdfData,
|
|
diffuseLighting, specularLighting);
|
|
#else
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
float len = lightData.size.x;
|
|
float3 T = lightData.right;
|
|
|
|
float3 unL = positionWS - lightData.positionWS;
|
|
|
|
// Pick the major axis of the ellipsoid.
|
|
float3 axis = lightData.right;
|
|
|
|
// We define the ellipsoid s.t. r1 = (r + len / 2), r2 = r3 = r.
|
|
// TODO: This could be precomputed.
|
|
float radius = rsqrt(lightData.invSqrAttenuationRadius);
|
|
float invAspectRatio = radius / (radius + (0.5 * len));
|
|
|
|
// Compute the light attenuation.
|
|
float intensity = GetEllipsoidalDistanceAttenuation(unL, lightData.invSqrAttenuationRadius,
|
|
axis, invAspectRatio);
|
|
|
|
// Terminate if the shaded point is too far away.
|
|
if (intensity == 0.0) return;
|
|
|
|
lightData.diffuseScale *= intensity;
|
|
lightData.specularScale *= intensity;
|
|
|
|
// TODO: This could be precomputed.
|
|
float3 P1 = lightData.positionWS - T * (0.5 * len);
|
|
float3 P2 = lightData.positionWS + T * (0.5 * len);
|
|
|
|
// Translate the endpoints s.t. the shaded point is at the origin of the coordinate system.
|
|
P1 -= positionWS;
|
|
P2 -= positionWS;
|
|
|
|
// Construct an orthonormal basis (local coordinate system) around N.
|
|
// TODO: it could be stored in PreLightData. All LTC lights compute it more than once!
|
|
// Also consider using 'bsdfData.tangentWS', 'bsdfData.bitangentWS', 'bsdfData.normalWS'.
|
|
float3x3 basis;
|
|
basis[0] = normalize(V - bsdfData.normalWS * preLightData.NdotV);
|
|
basis[1] = normalize(cross(bsdfData.normalWS, basis[0]));
|
|
basis[2] = bsdfData.normalWS;
|
|
|
|
// Rotate the endpoints into the local coordinate system (left-handed).
|
|
P1 = mul(P1, transpose(basis));
|
|
P2 = mul(P2, transpose(basis));
|
|
|
|
// Compute the binormal.
|
|
float3 B = normalize(cross(P1, P2));
|
|
|
|
float ltcValue;
|
|
|
|
// Evaluate the diffuse part.
|
|
{
|
|
#ifdef LIT_DIFFUSE_LAMBERT_BRDF
|
|
ltcValue = LTCEvaluate(P1, P2, B, k_identity3x3);
|
|
#else
|
|
ltcValue = LTCEvaluate(P1, P2, B, preLightData.ltcXformDisneyDiffuse);
|
|
#endif
|
|
|
|
if (ltcValue == 0.0)
|
|
{
|
|
// The light is below the horizon.
|
|
return;
|
|
}
|
|
|
|
#ifndef LIT_DIFFUSE_LAMBERT_BRDF
|
|
ltcValue *= preLightData.ltcDisneyDiffuseMagnitude;
|
|
#endif
|
|
|
|
ltcValue *= lightData.diffuseScale;
|
|
diffuseLighting = bsdfData.diffuseColor * lightData.color * ltcValue;
|
|
}
|
|
|
|
// Evaluate the specular part.
|
|
{
|
|
// TODO: the fit seems rather poor. The scaling factor of 0.5 allows us
|
|
// to match the reference for rough metals, but further darkens dielectrics.
|
|
float3 fresnelTerm = bsdfData.fresnel0 * preLightData.ltcGGXFresnelMagnitudeDiff
|
|
+ (float3)preLightData.ltcGGXFresnelMagnitude;
|
|
|
|
ltcValue = LTCEvaluate(P1, P2, B, preLightData.ltcXformGGX);
|
|
ltcValue *= lightData.specularScale;
|
|
specularLighting = fresnelTerm * lightData.color * ltcValue;
|
|
}
|
|
#endif // LIT_DISPLAY_REFERENCE_AREA
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Area - Reference
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void IntegrateBSDF_AreaRef(float3 V, float3 positionWS,
|
|
PreLightData preLightData, LightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting, out float3 specularLighting,
|
|
uint sampleCount = 512)
|
|
{
|
|
// Add some jittering on Hammersley2d
|
|
float2 randNum = InitRandom(V.xy * 0.5 + 0.5);
|
|
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
for (uint i = 0; i < sampleCount; ++i)
|
|
{
|
|
float3 P = float3(0.0, 0.0, 0.0); // Sample light point. Random point on the light shape in local space.
|
|
float3 Ns = float3(0.0, 0.0, 0.0); // Unit surface normal at P
|
|
float lightPdf = 0.0; // Pdf of the light sample
|
|
|
|
float2 u = Hammersley2d(i, sampleCount);
|
|
u = frac(u + randNum + 0.5);
|
|
|
|
float4x4 localToWorld = float4x4(float4(lightData.right, 0.0), float4(lightData.up, 0.0), float4(lightData.forward, 0.0), float4(lightData.positionWS, 1.0));
|
|
|
|
switch (lightData.lightType)
|
|
{
|
|
case GPULIGHTTYPE_SPHERE:
|
|
SampleSphere(u, localToWorld, lightData.size.x, lightPdf, P, Ns);
|
|
break;
|
|
case GPULIGHTTYPE_HEMISPHERE:
|
|
SampleHemisphere(u, localToWorld, lightData.size.x, lightPdf, P, Ns);
|
|
break;
|
|
case GPULIGHTTYPE_CYLINDER:
|
|
SampleCylinder(u, localToWorld, lightData.size.x, lightData.size.y, lightPdf, P, Ns);
|
|
break;
|
|
case GPULIGHTTYPE_RECTANGLE:
|
|
SampleRectangle(u, localToWorld, lightData.size.x, lightData.size.y, lightPdf, P, Ns);
|
|
break;
|
|
case GPULIGHTTYPE_DISK:
|
|
SampleDisk(u, localToWorld, lightData.size.x, lightPdf, P, Ns);
|
|
break;
|
|
// case GPULIGHTTYPE_LINE: handled by a separate function.
|
|
}
|
|
|
|
// Get distance
|
|
float3 unL = P - positionWS;
|
|
float sqrDist = dot(unL, unL);
|
|
float3 L = normalize(unL);
|
|
|
|
// Cosine of the angle between the light direction and the normal of the light's surface.
|
|
float cosLNs = dot(-L, Ns);
|
|
cosLNs = lightData.twoSided ? abs(cosLNs) : saturate(cosLNs);
|
|
|
|
// We calculate area reference light with the area integral rather than the solid angle one.
|
|
float illuminance = cosLNs * saturate(dot(bsdfData.normalWS, L)) / (sqrDist * lightPdf);
|
|
|
|
float3 localDiffuseLighting = float3(0.0, 0.0, 0.0);
|
|
float3 localSpecularLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
if (illuminance > 0.0)
|
|
{
|
|
BSDF(V, L, positionWS, preLightData, bsdfData, localDiffuseLighting, localSpecularLighting);
|
|
localDiffuseLighting *= lightData.color * illuminance * lightData.diffuseScale;
|
|
localSpecularLighting *= lightData.color * illuminance * lightData.specularScale;
|
|
}
|
|
|
|
diffuseLighting += localDiffuseLighting;
|
|
specularLighting += localSpecularLighting;
|
|
}
|
|
|
|
diffuseLighting /= float(sampleCount);
|
|
specularLighting /= float(sampleCount);
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Area - Approximation with Linearly Transformed Cosines
|
|
//-----------------------------------------------------------------------------
|
|
|
|
// #define ELLIPSOIDAL_ATTENUATION
|
|
|
|
void EvaluateBSDF_Area(LightLoopContext lightLoopContext,
|
|
float3 V, PositionInputs posInput,
|
|
PreLightData preLightData, LightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting, out float3 specularLighting)
|
|
{
|
|
float3 positionWS = posInput.positionWS;
|
|
|
|
#ifdef LIT_DISPLAY_REFERENCE_AREA
|
|
IntegrateBSDF_AreaRef(V, positionWS, preLightData, lightData, bsdfData,
|
|
diffuseLighting, specularLighting);
|
|
#else
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
specularLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
// TODO: This could be precomputed.
|
|
float halfWidth = lightData.size.x * 0.5;
|
|
float halfHeight = lightData.size.y * 0.5;
|
|
|
|
float3 unL = positionWS - lightData.positionWS;
|
|
|
|
// Rotate the light direction into the light space.
|
|
float3x3 lightToWorld = float3x3(lightData.right, lightData.up, lightData.forward);
|
|
unL = mul(unL, transpose(lightToWorld));
|
|
|
|
// Define the dimensions of the attenuation volume.
|
|
// TODO: This could be precomputed.
|
|
float radius = rsqrt(lightData.invSqrAttenuationRadius);
|
|
float3 invHalfDim = rcp(float3(radius + halfWidth,
|
|
radius + halfHeight,
|
|
radius));
|
|
|
|
// Compute the light attenuation.
|
|
#ifdef ELLIPSOIDAL_ATTENUATION
|
|
// The attenuation volume is an axis-aligned ellipsoid s.t.
|
|
// r1 = (r + w / 2), r2 = (r + h / 2), r3 = r.
|
|
float intensity = GetEllipsoidalDistanceAttenuation(unL, invHalfDim);
|
|
#else
|
|
// The attenuation volume is an axis-aligned box s.t.
|
|
// hX = (r + w / 2), hY = (r + h / 2), hZ = r.
|
|
float intensity = GetBoxDistanceAttenuation(unL, invHalfDim);
|
|
#endif
|
|
|
|
// Terminate if the shaded point is too far away.
|
|
if (intensity == 0.0) return;
|
|
|
|
lightData.diffuseScale *= intensity;
|
|
lightData.specularScale *= intensity;
|
|
|
|
// TODO: store 4 points and save 12 cycles (24x MADs - 12x MOVs).
|
|
float3 p0 = lightData.positionWS + lightData.right * -halfWidth + lightData.up * halfHeight;
|
|
float3 p1 = lightData.positionWS + lightData.right * -halfWidth + lightData.up * -halfHeight;
|
|
float3 p2 = lightData.positionWS + lightData.right * halfWidth + lightData.up * -halfHeight;
|
|
float3 p3 = lightData.positionWS + lightData.right * halfWidth + lightData.up * halfHeight;
|
|
|
|
float4x3 matL = float4x3(p0, p1, p2, p3) - float4x3(positionWS, positionWS, positionWS, positionWS);
|
|
|
|
float ltcValue;
|
|
|
|
// Evaluate the diffuse part.
|
|
{
|
|
#ifdef LIT_DIFFUSE_LAMBERT_BRDF
|
|
ltcValue = LTCEvaluate(matL, V, bsdfData.normalWS, preLightData.NdotV, lightData.twoSided,
|
|
k_identity3x3);
|
|
#else
|
|
ltcValue = LTCEvaluate(matL, V, bsdfData.normalWS, preLightData.NdotV, lightData.twoSided,
|
|
preLightData.ltcXformDisneyDiffuse);
|
|
#endif
|
|
|
|
if (ltcValue == 0.0)
|
|
{
|
|
// The polygon is either back-facing, or has been completely clipped.
|
|
return;
|
|
}
|
|
|
|
#ifndef LIT_DIFFUSE_LAMBERT_BRDF
|
|
ltcValue *= preLightData.ltcDisneyDiffuseMagnitude;
|
|
#endif
|
|
|
|
ltcValue *= lightData.diffuseScale;
|
|
diffuseLighting = bsdfData.diffuseColor * lightData.color * ltcValue;
|
|
}
|
|
|
|
// Evaluate the specular part.
|
|
{
|
|
// TODO: the fit seems rather poor. The scaling factor of 0.5 allows us
|
|
// to match the reference for rough metals, but further darkens dielectrics.
|
|
float3 fresnelTerm = bsdfData.fresnel0 * preLightData.ltcGGXFresnelMagnitudeDiff
|
|
+ (float3)preLightData.ltcGGXFresnelMagnitude;
|
|
|
|
ltcValue = LTCEvaluate(matL, V, bsdfData.normalWS, preLightData.NdotV, lightData.twoSided,
|
|
preLightData.ltcXformGGX);
|
|
ltcValue *= lightData.specularScale;
|
|
specularLighting = fresnelTerm * lightData.color * ltcValue;
|
|
}
|
|
#endif // LIT_DISPLAY_REFERENCE_AREA
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Env - Reference
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// Ref: Moving Frostbite to PBR (Appendix A)
|
|
float3 IntegrateLambertIBLRef( LightLoopContext lightLoopContext,
|
|
EnvLightData lightData, BSDFData bsdfData,
|
|
uint sampleCount = 2048)
|
|
{
|
|
float3 N = bsdfData.normalWS;
|
|
float3 tangentX = bsdfData.tangentWS;
|
|
float3x3 localToWorld = GetLocalFrame(N, tangentX);
|
|
float3 acc = float3(0.0, 0.0, 0.0);
|
|
|
|
// Add some jittering on Hammersley2d
|
|
float2 randNum = InitRandom(N.xy * 0.5 + 0.5);
|
|
|
|
for (uint i = 0; i < sampleCount; ++i)
|
|
{
|
|
float2 u = Hammersley2d(i, sampleCount);
|
|
u = frac(u + randNum + 0.5);
|
|
|
|
float3 L;
|
|
float NdotL;
|
|
float weightOverPdf;
|
|
ImportanceSampleLambert(u, localToWorld, L, NdotL, weightOverPdf);
|
|
|
|
if (NdotL > 0.0)
|
|
{
|
|
float4 val = SampleEnv(lightLoopContext, lightData.envIndex, L, 0);
|
|
|
|
// diffuse Albedo is apply here as describe in ImportanceSampleLambert function
|
|
acc += bsdfData.diffuseColor * LambertNoPI() * weightOverPdf * val.rgb;
|
|
}
|
|
}
|
|
|
|
return acc / sampleCount;
|
|
}
|
|
|
|
float3 IntegrateDisneyDiffuseIBLRef(LightLoopContext lightLoopContext,
|
|
float3 V, EnvLightData lightData, BSDFData bsdfData,
|
|
uint sampleCount = 2048)
|
|
{
|
|
float3 N = bsdfData.normalWS;
|
|
float3 tangentX = bsdfData.tangentWS;
|
|
float3x3 localToWorld = GetLocalFrame(N, tangentX);
|
|
float NdotV = GetShiftedNdotV(N, V, false);
|
|
float3 acc = float3(0.0, 0.0, 0.0);
|
|
|
|
// Add some jittering on Hammersley2d
|
|
float2 randNum = InitRandom(N.xy * 0.5 + 0.5);
|
|
|
|
for (uint i = 0; i < sampleCount; ++i)
|
|
{
|
|
float2 u = Hammersley2d(i, sampleCount);
|
|
u = frac(u + randNum + 0.5);
|
|
|
|
float3 L;
|
|
float NdotL;
|
|
float weightOverPdf;
|
|
// for Disney we still use a Cosine importance sampling, true Disney importance sampling imply a look up table
|
|
ImportanceSampleLambert(u, localToWorld, L, NdotL, weightOverPdf);
|
|
|
|
if (NdotL > 0.0)
|
|
{
|
|
float3 H = normalize(L + V);
|
|
float LdotH = dot(L, H);
|
|
// Note: we call DisneyDiffuse that require to multiply by Albedo / PI. Divide by PI is already taken into account
|
|
// in weightOverPdf of ImportanceSampleLambert call.
|
|
float disneyDiffuse = DisneyDiffuse(NdotV, NdotL, LdotH, bsdfData.perceptualRoughness);
|
|
|
|
// diffuse Albedo is apply here as describe in ImportanceSampleLambert function
|
|
float4 val = SampleEnv(lightLoopContext, lightData.envIndex, L, 0);
|
|
acc += bsdfData.diffuseColor * disneyDiffuse * weightOverPdf * val.rgb;
|
|
}
|
|
}
|
|
|
|
return acc / sampleCount;
|
|
}
|
|
|
|
// Ref: Moving Frostbite to PBR (Appendix A)
|
|
float3 IntegrateSpecularGGXIBLRef( LightLoopContext lightLoopContext,
|
|
float3 V, EnvLightData lightData, BSDFData bsdfData,
|
|
uint sampleCount = 2048)
|
|
{
|
|
float3 N = bsdfData.normalWS;
|
|
float3 tangentX = bsdfData.tangentWS;
|
|
float3 tangentY = bsdfData.bitangentWS;
|
|
float3x3 localToWorld = GetLocalFrame(N, tangentX);
|
|
float NdotV = GetShiftedNdotV(N, V, false);
|
|
float3 acc = float3(0.0, 0.0, 0.0);
|
|
|
|
// Add some jittering on Hammersley2d
|
|
float2 randNum = InitRandom(V.xy * 0.5 + 0.5);
|
|
|
|
for (uint i = 0; i < sampleCount; ++i)
|
|
{
|
|
float2 u = Hammersley2d(i, sampleCount);
|
|
u = frac(u + randNum + 0.5);
|
|
|
|
float VdotH;
|
|
float NdotL;
|
|
float3 L;
|
|
float weightOverPdf;
|
|
|
|
// GGX BRDF
|
|
if (bsdfData.materialId = MATERIALID_LIT_ANISO)
|
|
{
|
|
ImportanceSampleAnisoGGX(u, V, N, tangentX, tangentY, bsdfData.roughnessT, bsdfData.roughnessB, NdotV, L, VdotH, NdotL, weightOverPdf);
|
|
}
|
|
else
|
|
{
|
|
ImportanceSampleGGX(u, V, localToWorld, bsdfData.roughness, NdotV, L, VdotH, NdotL, weightOverPdf);
|
|
}
|
|
|
|
|
|
if (NdotL > 0.0)
|
|
{
|
|
// Fresnel component is apply here as describe in ImportanceSampleGGX function
|
|
float3 FweightOverPdf = F_Schlick(bsdfData.fresnel0, VdotH) * weightOverPdf;
|
|
|
|
float4 val = SampleEnv(lightLoopContext, lightData.envIndex, L, 0);
|
|
|
|
acc += FweightOverPdf * val.rgb;
|
|
}
|
|
}
|
|
|
|
return acc / sampleCount;
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// EvaluateBSDF_Env
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// _preIntegratedFGD and _CubemapLD are unique for each BRDF
|
|
void EvaluateBSDF_Env( LightLoopContext lightLoopContext,
|
|
float3 V, PositionInputs posInput, PreLightData preLightData, EnvLightData lightData, BSDFData bsdfData,
|
|
out float3 diffuseLighting, out float3 specularLighting, out float2 weight)
|
|
{
|
|
float3 positionWS = posInput.positionWS;
|
|
|
|
#ifdef LIT_DISPLAY_REFERENCE_IBL
|
|
|
|
specularLighting = IntegrateSpecularGGXIBLRef(lightLoopContext, V, lightData, bsdfData);
|
|
|
|
/*
|
|
#ifdef LIT_DIFFUSE_LAMBERT_BRDF
|
|
diffuseLighting = IntegrateLambertIBLRef(lightData, bsdfData);
|
|
#else
|
|
diffuseLighting = IntegrateDisneyDiffuseIBLRef(lightLoopContext, V, lightData, bsdfData);
|
|
#endif
|
|
*/
|
|
diffuseLighting = float3(0.0, 0.0, 0.0);
|
|
|
|
weight = float2(0.0, 1.0);
|
|
|
|
#else
|
|
// TODO: factor this code in common, so other material authoring don't require to rewrite everything,
|
|
// also think about how such a loop can handle 2 cubemap at the same time as old unity. Macro can allow to do that
|
|
// but we need to have UNITY_SAMPLE_ENV_LOD replace by a true function instead that is define by the lighting arcitecture.
|
|
// Also not sure how to deal with 2 intersection....
|
|
// Box and sphere are related to light property (but we have also distance based roughness etc...)
|
|
|
|
// TODO: test the strech from Tomasz
|
|
// float shrinkedRoughness = AnisotropicStrechAtGrazingAngle(bsdfData.roughness, bsdfData.perceptualRoughness, NdotV);
|
|
|
|
// In this code we redefine a bit the behavior of the reflcetion proble. We separate the projection volume (the proxy of the scene) form the influence volume (what pixel on the screen is affected)
|
|
|
|
// 1. First determine the projection volume
|
|
|
|
// In Unity the cubemaps are capture with the localToWorld transform of the component.
|
|
// This mean that location and oritention matter. So after intersection of proxy volume we need to convert back to world.
|
|
|
|
// CAUTION: localToWorld is the transform use to convert the cubemap capture point to world space (mean it include the offset)
|
|
// the center of the bounding box is thus in locals space: positionLS - offsetLS
|
|
// We use this formulation as it is the one of legacy unity that was using only AABB box.
|
|
|
|
float3 R = preLightData.iblDirWS;
|
|
float3x3 worldToLocal = transpose(float3x3(lightData.right, lightData.up, lightData.forward)); // worldToLocal assume no scaling
|
|
float3 positionLS = positionWS - lightData.positionWS;
|
|
positionLS = mul(positionLS, worldToLocal).xyz - lightData.offsetLS; // We want to calculate the intersection from the center of the bounding box.
|
|
|
|
if (lightData.envShapeType == ENVSHAPETYPE_BOX)
|
|
{
|
|
float3 dirLS = mul(R, worldToLocal);
|
|
float3 boxOuterDistance = lightData.innerDistance + float3(lightData.blendDistance, lightData.blendDistance, lightData.blendDistance);
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float dist = BoxRayIntersectSimple(positionLS, dirLS, -boxOuterDistance, boxOuterDistance);
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// No need to normalize for fetching cubemap
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// We can reuse dist calculate in LS directly in WS as there is no scaling. Also the offset is already include in lightData.positionWS
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R = (positionWS + dist * R) - lightData.positionWS;
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// TODO: add distance based roughness
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}
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else if (lightData.envShapeType == ENVSHAPETYPE_SPHERE)
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{
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float3 dirLS = mul(R, worldToLocal);
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float sphereOuterDistance = lightData.innerDistance.x + lightData.blendDistance;
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float dist = SphereRayIntersectSimple(positionLS, dirLS, sphereOuterDistance);
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R = (positionWS + dist * R) - lightData.positionWS;
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}
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// 2. Apply the influence volume (Box volume is used for culling whatever the influence shape)
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// TODO: In the future we could have an influence volume inside the projection volume (so with a different transform, in this case we will need another transform)
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weight.y = 1.0;
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if (lightData.envShapeType == ENVSHAPETYPE_SPHERE)
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{
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float distFade = max(length(positionLS) - lightData.innerDistance.x, 0.0);
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weight.y = saturate(1.0 - distFade / max(lightData.blendDistance, 0.0001)); // avoid divide by zero
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}
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else if (lightData.envShapeType == ENVSHAPETYPE_BOX ||
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lightData.envShapeType == ENVSHAPETYPE_NONE)
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{
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// Calculate falloff value, so reflections on the edges of the volume would gradually blend to previous reflection.
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float distFade = DistancePointBox(positionLS, -lightData.innerDistance, lightData.innerDistance);
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weight.y = saturate(1.0 - distFade / max(lightData.blendDistance, 0.0001)); // avoid divide by zero
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}
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// Smooth weighting
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weight.x = 0.0;
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weight.y = smoothstep01(weight.y);
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// TODO: we must always perform a weight calculation as due to tiled rendering we need to smooth out cubemap at boundaries.
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// So goal is to split into two category and have an option to say if we parallax correct or not.
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// TODO: compare current Morten version: offline cubemap with a particular remap + the bias in perceptualRoughnessToMipmapLevel
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// to classic remap like unreal/Frobiste. The function GetSpecularDominantDir can result in a better matching in this case
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// We let GetSpecularDominantDir currently as it still an improvement but not as good as it could be
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float mip = perceptualRoughnessToMipmapLevel(bsdfData.perceptualRoughness);
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float4 preLD = SampleEnv(lightLoopContext, lightData.envIndex, R, mip);
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specularLighting = preLD.rgb * preLightData.specularFGD;
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// Apply specular occlusion on it
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specularLighting *= bsdfData.specularOcclusion;
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diffuseLighting = float3(0.0, 0.0, 0.0);
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#endif
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}
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#endif // #ifdef HAS_LIGHTLOOP
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