public override void GenerateShader(MaterialGeneratorContext context)
{
// determine if an tessellation material have already been added in another layer
hasAlreadyTessellationFeature = context.GetStreamFinalModifier <MaterialTessellationBaseFeature>(MaterialShaderStage.Domain) != null;
// Notify problem on multiple tessellation techniques and return
if (hasAlreadyTessellationFeature)
{
context.Log.Warning("A material cannot have more than one layer performing tessellation. The first tessellation method found, will be used.");
return;
}
// reset the tessellation stream at the beginning of the stage
context.AddStreamInitializer(MaterialShaderStage.Domain, "MaterialTessellationStream");
// set the desired triangle size desired for this material
context.Parameters.Set(TessellationKeys.DesiredTriangleSize, TriangleSize);
// set the tessellation method and callback to add Displacement/Normal average shaders.
if (AdjacentEdgeAverage && !context.Tags.Get(HasFinalCallback))
{
context.Tags.Set(HasFinalCallback, true);
context.MaterialPass.TessellationMethod = StrideTessellationMethod.AdjacentEdgeAverage;
context.AddFinalCallback(MaterialShaderStage.Domain, AddAdjacentEdgeAverageMacros);
context.AddFinalCallback(MaterialShaderStage.Domain, AddAdjacentEdgeAverageShaders);
}
}
public void AddAdjacentEdgeAverageShaders(MaterialShaderStage stage, MaterialGeneratorContext context)
{
var tessellationShader = context.Parameters.Get(MaterialKeys.TessellationShader) as ShaderMixinSource;
if (tessellationShader == null)
{
return;
}
if (context.GetStreamFinalModifier <MaterialDisplacementMapFeature>(MaterialShaderStage.Domain) != null)
{
tessellationShader.Mixins.Add(new ShaderClassSource("TessellationAE2", "TexCoord")); // this suppose Displacement from Texture -> TODO make it more flexible so that it works with any kind of displacement.
tessellationShader.Mixins.Add(new ShaderClassSource("TessellationAE3", "normalWS"));
}
}