Fix export of metallic and normal texture map. Add support for any shader that can support metallic roughness workflow.

UnityGLTF/Assets/Resources/MetalGlossChannelSwap.shader

@@ -0,0 +1,61 @@
+Shader "Hidden/MetalGlossChannelSwap"
+{
+	Properties
+	{
+		_MainTex ("Texture", 2D) = "white" {}
+	}
+	SubShader
+	{
+		// No culling or depth
+		Cull Off ZWrite Off ZTest Always
+
+		Pass
+		{
+			CGPROGRAM
+			#pragma vertex vert
+			#pragma fragment frag
+
+			#include "UnityCG.cginc"
+
+			struct appdata
+			{
+				float4 vertex : POSITION;
+				float2 uv : TEXCOORD0;
+			};
+
+			struct v2f
+			{
+				float2 uv : TEXCOORD0;
+				float4 vertex : SV_POSITION;
+			};
+
+			v2f vert (appdata v)
+			{
+				v2f o;
+				o.vertex = UnityObjectToClipPos(v.vertex);
+				o.uv = v.uv;
+				return o;
+			}
+
+			sampler2D _MainTex;
+
+			float4 frag (v2f i) : SV_Target
+			{
+				float4 col = tex2D(_MainTex, i.uv);
+				// From the GLTF 2.0 spec
+				// The metallic-roughness texture. The metalness values are sampled from the B channel. 
+				// The roughness values are sampled from the G channel. These values are linear. 
+				// If other channels are present (R or A), they are ignored for metallic-roughness calculations.
+				//
+				// Unity, by default, puts metallic in R channel and glossiness in A channel.
+				// Unity uses a metallic-gloss texture so we need to invert the value in the g channel.
+				//
+				// Conversion Summary
+				// Unity R channel goes into B channel
+				// Unity A channel goes into G channel, then inverted
+				return float4(1, 1 - col.a, col.r, 1);
+			}
+			ENDCG
+		}
+	}
+}

UnityGLTF/Assets/Resources/NormalChannel.shader

@@ -0,0 +1,52 @@
+Shader "Hidden/NormalChannel"
+{
+	Properties
+	{
+		_MainTex ("Texture", 2D) = "white" {}
+	}
+	SubShader
+	{
+		// No culling or depth
+		Cull Off ZWrite Off ZTest Always
+
+		Pass
+		{
+			CGPROGRAM
+			#pragma vertex vert
+			#pragma fragment frag
+
+			#include "UnityCG.cginc"
+
+			struct appdata
+			{
+				float4 vertex : POSITION;
+				float2 uv : TEXCOORD0;
+			};
+
+			struct v2f
+			{
+				float2 uv : TEXCOORD0;
+				float4 vertex : SV_POSITION;
+			};
+
+			v2f vert (appdata v)
+			{
+				v2f o;
+				o.vertex = UnityObjectToClipPos(v.vertex);
+				o.uv = v.uv;
+				return o;
+			}
+
+			sampler2D _MainTex;
+
+			fixed4 frag (v2f i) : SV_Target
+			{
+				float4 col = tex2D(_MainTex, i.uv);
+				// If a texture is marked as a normal map
+				// the values are stored in the A and G channel.
+				return float4(col.a, col.g, 1, 1);
+			}
+			ENDCG
+		}
+	}
+}

UnityGLTF/Assets/UnityGLTF/Examples/GLTFExporterTest.cs

@@ -5,10 +5,15 @@ namespace UnityGLTF.Examples
 {
 	public class GLTFExporterTest : MonoBehaviour
 	{
+		public string RetrieveTexturePath(UnityEngine.Texture texture)
+		{
+			return texture.name;
+		}
+
 		// Use this for initialization
 		void Awake()
 		{
-			var exporter = new GLTFSceneExporter(new[] {transform});
+			var exporter = new GLTFSceneExporter(new[] {transform}, RetrieveTexturePath);
 			var appPath = Application.dataPath;
 			var wwwPath = appPath.Substring(0, appPath.LastIndexOf("Assets")) + "www";
 			exporter.SaveGLTFandBin(Path.Combine(wwwPath, "TestScene"), "TestScene");

UnityGLTF/Assets/UnityGLTF/Scripts/Editor/GLTFExportMenu.cs

@@ -5,6 +5,11 @@
 
 public class GLTFExportMenu
 {
+	public static string RetrieveTexturePath(UnityEngine.Texture texture)
+	{
+		return AssetDatabase.GetAssetPath (texture);
+	}
+
 	[MenuItem("GLTF/Export Selected")]
 	static void ExportSelected()
 	{
@@ -16,9 +21,12 @@ static void ExportSelected()
 		else
 			throw new Exception("No objects selected, cannot export.");
 
-		var exporter = new GLTFSceneExporter(Selection.transforms);
+		var exporter = new GLTFSceneExporter(Selection.transforms, RetrieveTexturePath);
+
 		var path = EditorUtility.OpenFolderPanel("glTF Export Path", "", "");
-		exporter.SaveGLTFandBin(path, name);
+		if (!string.IsNullOrEmpty(path)) {
+			exporter.SaveGLTFandBin (path, name);
+		}
 	}
 
 	[MenuItem("GLTF/Export Scene")]
@@ -28,8 +36,10 @@ static void ExportScene()
 		var gameObjects = scene.GetRootGameObjects();
 		var transforms = Array.ConvertAll(gameObjects, gameObject => gameObject.transform);
 
-		var exporter = new GLTFSceneExporter(transforms);
+		var exporter = new GLTFSceneExporter(transforms, RetrieveTexturePath);
 		var path = EditorUtility.OpenFolderPanel("glTF Export Path", "", "");
-		exporter.SaveGLTFandBin(path, scene.name);
+		if (path != "") {
+			exporter.SaveGLTFandBin (path, scene.name);
+		}
 	}
 }

UnityGLTF/Assets/UnityGLTF/Scripts/Editor/PbrShaderGUI.cs

@@ -56,8 +56,6 @@ private static class Styles
         MaterialProperty bumpMap = null;
         MaterialProperty occlusionStrength = null;
         MaterialProperty occlusionMap = null;
-        MaterialProperty heigtMapScale = null;
-        MaterialProperty heightMap = null;
         MaterialProperty emissionColor = null;
         MaterialProperty emissionMap = null;
 

UnityGLTF/Assets/UnityGLTF/Scripts/GLTFComponent.cs

@@ -26,11 +26,11 @@ IEnumerator Start()
 			ILoader loader = null;
 
 			if (UseStream)
-			{
-                // Path.Combine treats paths that start with the separator character
-                // as absolute paths, ignoring the first path passed in. This removes
-                // that character to properly handle a filename written with it.
-                GLTFUri = GLTFUri.TrimStart(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar });
+			{
+                // Path.Combine treats paths that start with the separator character
+                // as absolute paths, ignoring the first path passed in. This removes
+                // that character to properly handle a filename written with it.
+                GLTFUri = GLTFUri.TrimStart(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar });
                 string fullPath = Path.Combine(Application.streamingAssetsPath, GLTFUri);
 				string directoryPath = URIHelper.GetDirectoryName(fullPath);
 				loader = new FileLoader(directoryPath);