Feeds a source material.

The returned material will be assigned to the renderer. If you return null, Unity will use its default material finding / generation method to assign a material. The sourceMaterial is generated directly from the model before importing and will be destroyed immediately after OnAssignMaterial.

	class MyMeshPostprocessor extends AssetPostprocessor {
		function OnAssignMaterialModel (material : Material, renderer : Renderer) : Material {
			var materialPath = "Assets/" + material.name + ".mat";
			// Find if there is a material at the material path
			// Turn this off to always regeneration materials
			if (AssetDatabase.LoadAssetAtPath(materialPath, typeof(Material)))
				return AssetDatabase.LoadAssetAtPath(materialPath, typeof(Material));
			
			// Create a new material asset using the specular shader
			// but otherwise the default values from the model
			material.shader = Shader.Find("Specular");
			AssetDatabase.CreateAsset(material, "Assets/" + material.name + ".mat");
			return material;
		}
	}