/// <summary>
/// <para>Get the special ZWrite material used to address the Order
/// Independent Transparency (OIT) problem when using URP
/// (Universal Render Pipeline). For background about the OIT
/// problem, see:
/// https://forum.unity.com/threads/render-mode-transparent-doesnt-work-see-video.357853/#post-2315934.</para>
/// <para>The ZWrite material writes only to the Z-buffer
/// (a.k.a. depth buffer) and not to the RGBA framebuffer like
/// a normal shader would. With the built-in render pipeline,
/// we can do the Z-write-only pass by adding a (preliminary)
/// pass to the shader that renders the mesh. However, since URP
/// only supports single-pass shaders, we must instead
/// emulate two shader passes by assigning two materials to
/// the mesh.</para>
/// <para>Note!: This method must be called after populating
/// the `Materials` array with all of the materials
/// from the glTF file. Otherwise, the indices in the
/// `Materials` array will not match the material indices
/// in the glTF file, and the importer will assign the wrong
/// materials to the meshes.</para>
/// </summary>
/// <param name="create">
/// create the ZWrite material if it does not already exist
/// </param>
public Material GetZWriteMaterial(bool create)
{
if (ZWriteMaterialIndex < 0)
{
if (!create)
{
return(null);
}
var pipeline = RenderPipelineUtil.GetRenderPipeline(true);
if (pipeline != RenderPipelineType.URP)
{
throw new Exception("ZWrite material can only be used with URP");
}
ZWriteMaterialIndex = Materials.Count;
var shader = Shader.Find("Piglet/URPZWrite");
var zwrite = new Material(shader)
{
name = "zwrite"
};
Materials.Add(zwrite);
}
return(Materials[ZWriteMaterialIndex]);
}
/// <summary>
/// <para>Get the default material, which is used whenever
/// a mesh is not explicitly assigned a material.</para>
/// <para>Note!: This method must be called after populating
/// the `Materials` array with all of the materials
/// from the glTF file. Otherwise, the indices in the
/// `Materials` array will not match the material indices
/// in the glTF file, and the importer will assign the wrong
/// materials to the meshes.</para>
/// </summary>
/// <param name="create">
/// create the default material if it does not already exist
/// </param>
public Material GetDefaultMaterial(bool create)
{
if (DefaultMaterialIndex < 0)
{
if (!create)
{
return(null);
}
string shaderName;
var pipeline = RenderPipelineUtil.GetRenderPipeline(true);
switch (pipeline)
{
case RenderPipelineType.BuiltIn:
shaderName = "Piglet/MetallicRoughnessOpaque";
break;
case RenderPipelineType.URP:
shaderName = "Shader Graphs/URPMetallicRoughnessOpaque";
break;
default:
throw new Exception("current render pipeline unsupported, " +
" GetRenderPipeline should have thrown exception");
}
Shader shader = Shader.Find(shaderName);
if (shader == null)
{
if (pipeline == RenderPipelineType.URP)
{
throw new Exception(String.Format(
"Piglet failed to load URP shader \"{0}\". Please ensure that " +
"you have installed the URP shaders from the appropriate .unitypackage " +
"in Assets/Piglet/Extras, and that the shaders are being included " +
"your build.",
shaderName));
}
throw new Exception(String.Format(
"Piglet failed to load shader \"{0}\". Please ensure that " +
"this shader is being included your build.",
shaderName));
}
DefaultMaterialIndex = Materials.Count;
var material = new Material(shader)
{
name = "default"
};
Materials.Add(material);
}
return(Materials[DefaultMaterialIndex]);
}
