private void AddMaterialToArrayAndDictionary(ScatteringParameters scatteringParameters, uint materialArrayIndex)
{
// "SetScatteringWidth()" throws an exception if the range is exceeded. // TODO: How to handle this? Don't throw at all?
SubsurfaceScatteringBlurEffect.SetScatteringWidth(materialArrayIndex, scatteringParameters.ScatteringWidth); // Add the scattering width to the scattering width array.
if (scatteringParameters.ScatteringKernel != null)
{
// TODO: STABILITY: What to do if the scattering width is present but no kernel? The post-process wouldn't be able to handle that correctly.
// Maybe just save a dummy kernel?
SubsurfaceScatteringBlurEffect.SetScatteringKernel(materialArrayIndex, scatteringParameters.ScatteringKernel);
}
scatteringParametersToArrayIndexDictionary[scatteringParameters] = materialArrayIndex; // Add the material to the dictionary and save its associated index in the scattering width array.
}
/// <inheritdoc/>
public override void Prepare(RenderDrawContext context)
{
if (DeduplicateMaterialParameters)
{
scatteringParametersToArrayIndexDictionary.Clear();
}
// TODO: Generate a material array per view? This could in some cases limit the number of materials present in the array.
// In case every object is visible from every view, it wouldn't save us anything though.
uint materialArrayIndexCounter = 1; // We start at index 1 instead of 0 because we use index 0 to flag (and discard) non-scattering materials.
// TODO: Not sure if the following line is even necessary, because we don't use any material parameters of material 0 anyway. I mean not even the kernel of material 0 is set. So either set both or none.
SubsurfaceScatteringBlurEffect.SetScatteringWidth(0, 0.0f); // This element is unused because a material index of 0 means the material is not a subsurface scattering material and therefore will be skipped by the post-process.
// Generate the material dictionary that contains only scattering materials:
//Dispatcher.ForEach(((RootEffectRenderFeature)RootRenderFeature).RenderNodes, (ref RenderNode renderNode) => // TODO: PERFORMANCE: Use this instead?
foreach (RenderNode renderNode in ((RootEffectRenderFeature)RootRenderFeature).RenderNodes)
{
var perDrawLayout = renderNode.RenderEffect?.Reflection?.PerDrawLayout;
if (perDrawLayout == null)
{
continue;
}
var renderMesh = (RenderMesh)renderNode.RenderObject;
uint materialArrayIndex = 0; // If the mesh doesn't have a scattering kernel we write index 0 into the constant buffer.
if (HasScatteringKernel(renderMesh.MaterialPass))
{
materialArrayIndex = AddMaterialToDictionaryAndGetArrayIndex(renderMesh, ref materialArrayIndexCounter);
}
WriteMaterialIndexIntoRenderNodeConstantBuffer(perDrawLayout, renderNode, materialArrayIndex);
}
bool scatteringMaterialsAreVisible = (materialArrayIndexCounter > 1);
SubsurfaceScatteringBlurEffect.Enabled = scatteringMaterialsAreVisible; // Disable the post-process if no scattering objects are visible (to save performance).
}