fix: some TMPro materials were not exported properly

UnityGLTF/Assets/UnityGLTF/Runtime/Scripts/Extensions/TextMeshExport.cs

@@ -31,8 +31,19 @@ private static void CleanUpRenderTextureCache(GLTFSceneExporter _, GLTFRoot __)
 
 		private static bool BeforeMaterialExport(GLTFSceneExporter exporter, GLTFRoot gltfRoot, Material material, GLTFMaterial materialNode)
 		{
-			if (material.shader.name.Contains("TextMeshPro"))
+			if (material.shader.name.Contains("TextMeshPro")) // seems to only work for TextMeshPro/Mobile/ right now (SDFAA_HINTED?)
 			{
+				var s = material.shader;
+				// TODO figure out how to properly use the non-mobile shaders
+				var newS = Shader.Find("TestMeshPro/Mobile/Distance Field");
+#if UNITY_EDITOR
+				if (!newS)
+				{
+					newS = UnityEditor.AssetDatabase.LoadAssetAtPath<Shader>(UnityEditor.AssetDatabase.GUIDToAssetPath("fe393ace9b354375a9cb14cdbbc28be4")); // same as above
+				}
+#endif
+				material.shader = newS;
+
 				if (!tempMat) tempMat = new Material(Shader.Find("Unlit/Transparent Cutout"));
 
 				var existingTex = material.mainTexture;
@@ -42,6 +53,7 @@ private static bool BeforeMaterialExport(GLTFSceneExporter exporter, GLTFRoot gl
 					var rt = new RenderTexture(existingTex.width, existingTex.height, 0, RenderTextureFormat.ARGB32);
 					if (material.HasProperty("_OutlineSoftness"))
 						material.SetFloat("_OutlineSoftness", 0);
+					// TODO figure out how to get this more smooth
 					Graphics.Blit(existingTex, rt, material);
 					rtCache[existingTex] = rt;
 					rt.anisoLevel = 9;
@@ -50,6 +62,7 @@ private static bool BeforeMaterialExport(GLTFSceneExporter exporter, GLTFRoot gl
 
 				tempMat.mainTexture = rtCache[existingTex];
 
+
 				exporter.ExportUnlit(materialNode, tempMat);
 
 				// export material
@@ -58,6 +71,11 @@ private static bool BeforeMaterialExport(GLTFSceneExporter exporter, GLTFRoot gl
 				materialNode.PbrMetallicRoughness.BaseColorFactor = Color.white.ToNumericsColorLinear();
 				materialNode.AlphaMode = AlphaMode.BLEND;
 
+				material.shader = s;
+#if UNITY_EDITOR
+				UnityEditor.EditorUtility.ClearDirty(material);
+#endif
+
 				return true;
 			}