public static void GetCornetteShanksPhaseFunction(ZonalHarmonicsL2 zh, float anisotropy)
{
float g = anisotropy;
zh.coeffs[0] = 0.282095f;
zh.coeffs[1] = 0.293162f * g * (4.0f + (g * g)) / (2.0f + (g * g));
zh.coeffs[2] = (0.126157f + 1.44179f * (g * g) + 0.324403f * (g * g) * (g * g)) / (2.0f + (g * g));
}
void SetPreconvolvedAmbientLightProbe(HDCamera hdCamera, CommandBuffer cmd, float dimmer, float anisotropy)
{
SphericalHarmonicsL2 probeSH = SphericalHarmonicMath.UndoCosineRescaling(m_SkyManager.GetAmbientProbe(hdCamera));
probeSH = SphericalHarmonicMath.RescaleCoefficients(probeSH, dimmer);
ZonalHarmonicsL2.GetCornetteShanksPhaseFunction(m_PhaseZH, anisotropy);
SphericalHarmonicsL2 finalSH = SphericalHarmonicMath.PremultiplyCoefficients(SphericalHarmonicMath.Convolve(probeSH, m_PhaseZH));
SphericalHarmonicMath.PackCoefficients(m_PackedCoeffs, finalSH);
cmd.SetGlobalVectorArray(HDShaderIDs._AmbientProbeCoeffs, m_PackedCoeffs);
}
public float[] coeffs; // Must have the size of 3
public static ZonalHarmonicsL2 GetHenyeyGreensteinPhaseFunction(float anisotropy)
{
float g = anisotropy;
var zh = new ZonalHarmonicsL2();
zh.coeffs = new float[3];
zh.coeffs[0] = 0.5f * Mathf.Sqrt(1.0f / Mathf.PI);
zh.coeffs[1] = 0.5f * Mathf.Sqrt(3.0f / Mathf.PI) * g;
zh.coeffs[2] = 0.5f * Mathf.Sqrt(5.0f / Mathf.PI) * g * g;
return(zh);
}
// Function that fills the buffer with the ambient probe values
unsafe void SetPreconvolvedAmbientLightProbe(ref ShaderVariablesClouds cb, HDCamera hdCamera, VolumetricClouds settings)
{
SphericalHarmonicsL2 probeSH = SphericalHarmonicMath.UndoCosineRescaling(m_SkyManager.GetAmbientProbe(hdCamera));
probeSH = SphericalHarmonicMath.RescaleCoefficients(probeSH, settings.ambientLightProbeDimmer.value);
ZonalHarmonicsL2.GetCornetteShanksPhaseFunction(m_PhaseZHClouds, 0.0f);
SphericalHarmonicsL2 finalSH = SphericalHarmonicMath.PremultiplyCoefficients(SphericalHarmonicMath.Convolve(probeSH, m_PhaseZHClouds));
SphericalHarmonicMath.PackCoefficients(m_PackedCoeffsClouds, finalSH);
for (int i = 0; i < 7; i++)
{
for (int j = 0; j < 4; ++j)
{
cb._AmbientProbeCoeffs[i * 4 + j] = m_PackedCoeffsClouds[i][j];
}
}
}
void InitializeVolumetricClouds()
{
// Keep track of the state for the release
m_ActiveVolumetricClouds = m_Asset.currentPlatformRenderPipelineSettings.supportVolumetricClouds;
if (!m_ActiveVolumetricClouds)
{
return;
}
// Allocate the buffers for ambient probe evaluation
m_PhaseZHClouds = new ZonalHarmonicsL2();
m_PhaseZHClouds.coeffs = new float[3];
// Grab the kernels we need
ComputeShader volumetricCloudsCS = m_Asset.renderPipelineResources.shaders.volumetricCloudsCS;
m_ConvertObliqueDepthKernel = volumetricCloudsCS.FindKernel("ConvertObliqueDepth");
m_CloudDownscaleDepthKernel = volumetricCloudsCS.FindKernel("DownscaleDepth");
m_CloudRenderKernel = volumetricCloudsCS.FindKernel("RenderClouds");
m_ReprojectCloudsKernel = volumetricCloudsCS.FindKernel("ReprojectClouds");
m_ReprojectCloudsRejectionKernel = volumetricCloudsCS.FindKernel("ReprojectCloudsRejection");
m_PreUpscaleCloudsKernel = volumetricCloudsCS.FindKernel("PreUpscaleClouds");
m_PreUpscaleCloudsSkyKernel = volumetricCloudsCS.FindKernel("PreUpscaleCloudsSky");
m_UpscaleAndCombineCloudsKernelColorCopy = volumetricCloudsCS.FindKernel("UpscaleAndCombineClouds_ColorCopy");
m_UpscaleAndCombineCloudsKernelColorRW = volumetricCloudsCS.FindKernel("UpscaleAndCombineClouds_ColorRW");
m_UpscaleAndCombineCloudsSkyKernel = volumetricCloudsCS.FindKernel("UpscaleAndCombineCloudsSky");
m_CombineCloudsKernelColorCopy = volumetricCloudsCS.FindKernel("CombineClouds_ColorCopy");
m_CombineCloudsKernelColorRW = volumetricCloudsCS.FindKernel("CombineClouds_ColorRW");
m_CombineCloudsSkyKernel = volumetricCloudsCS.FindKernel("CombineCloudsSky");
// Create the material needed for the combination
m_CloudCombinePass = CoreUtils.CreateEngineMaterial(defaultResources.shaders.volumetricCloudsCombinePS);
// Allocate all the texture initially
AllocatePresetTextures();
// Initialize the additional sub components
InitializeVolumetricCloudsMap();
InitializeVolumetricCloudsShadows();
InitializeVolumetricCloudsAmbientProbe();
}
// Ref: "Stupid Spherical Harmonics Tricks", p. 6.
public static SphericalHarmonicsL2 Convolve(SphericalHarmonicsL2 sh, ZonalHarmonicsL2 zh)
{
for (int l = 0; l <= 2; l++)
{
float n = Mathf.Sqrt((4.0f * Mathf.PI) / (2 * l + 1));
float k = zh.coeffs[l];
float p = n * k;
for (int m = -l; m <= l; m++)
{
int i = l * (l + 1) + m;
for (int c = 0; c < 3; c++)
{
sh[c, i] *= p;
}
}
}
return(sh);
}
void InitializeVolumetricLighting()
{
m_SupportVolumetrics = asset.currentPlatformRenderPipelineSettings.supportVolumetrics;
if (!m_SupportVolumetrics)
{
return;
}
m_VolumeVoxelizationCS = defaultResources.shaders.volumeVoxelizationCS;
m_VolumetricLightingCS = defaultResources.shaders.volumetricLightingCS;
m_VolumetricLightingFilteringCS = defaultResources.shaders.volumetricLightingFilteringCS;
m_PackedCoeffs = new Vector4[7];
m_PhaseZH = new ZonalHarmonicsL2();
m_PhaseZH.coeffs = new float[3];
m_xySeq = new Vector2[7];
m_PixelCoordToViewDirWS = new Matrix4x4[ShaderConfig.s_XrMaxViews];
CreateVolumetricLightingBuffers();
}
