Move coordinate space conversion into the UnityGLTF layer (#105)

* Moving coordinate system flipping into the Unity layer * Updating path creation for StreamingAssets * Adding documentation to GLTFUnityHelpers * Slight reworking of the helper functions to leave the passed in arrays untouched.
KhronosGroup · Jan 27, 2018 · 0682767 · 0682767
1 parent 36cd23b
commit 0682767
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Showing 6 changed files with 284 additions and 91 deletions.
diff --git a/GLTFSerialization/GLTFSerialization/Schema/Accessor.cs b/GLTFSerialization/GLTFSerialization/Schema/Accessor.cs
@@ -501,77 +501,45 @@ public Vector2[] AsTexcoordArray(ref NumericArray contents, byte[] bufferViewDat
 		{
 			if (contents.AsTexcoords != null) return contents.AsTexcoords;
 
-			var arr = AsVector2Array(ref contents, bufferViewData, offset);
-			for (var i = 0; i < arr.Length; i++)
-			{
-				arr[i].Y = 1 - arr[i].Y;
-			}
-
-			contents.AsTexcoords = arr;
+			contents.AsTexcoords = AsVector2Array(ref contents, bufferViewData, offset);
 
-			return arr;
+			return contents.AsTexcoords;
 		}
 
 		public Vector3[] AsVertexArray(ref NumericArray contents, byte[] bufferViewData, int offset)
 		{
 			if (contents.AsVertices != null) return contents.AsVertices;
 
-			var arr = AsVector3Array(ref contents, bufferViewData, offset);
-			for (var i = 0; i < arr.Length; i++)
-			{
-				arr[i].Z *= -1;
-			}
-
-			contents.AsVertices = arr;
+			contents.AsVertices = AsVector3Array(ref contents, bufferViewData, offset);
 
-			return arr;
+			return contents.AsVertices;
 		}
 
 		public Vector3[] AsNormalArray(ref NumericArray contents, byte[] bufferViewData, int offset)
 		{
 			if (contents.AsNormals != null) return contents.AsNormals;
 
-			var arr = AsVector3Array(ref contents, bufferViewData, offset);
-			for (var i = 0; i < arr.Length; i++)
-			{
-				arr[i].Z *= -1;
-			}
-
-			contents.AsNormals = arr;
+			contents.AsNormals = AsVector3Array(ref contents, bufferViewData, offset);
 
-			return arr;
+			return contents.AsNormals;
 		}
 
 		public Vector4[] AsTangentArray(ref NumericArray contents, byte[] bufferViewData, int offset)
 		{
 			if (contents.AsTangents != null) return contents.AsTangents;
 
-			var arr = AsVector4Array(ref contents, bufferViewData, offset);
-			for (var i = 0; i < arr.Length; i++)
-			{
-				arr[i].W *= -1;
-			}
-
-			contents.AsTangents = arr;
+			contents.AsTangents = AsVector4Array(ref contents, bufferViewData, offset);
 
-			return arr;
+			return contents.AsTangents;
 		}
 
 		public uint[] AsTriangles(ref NumericArray contents, byte[] bufferViewData, int offset)
 		{
 			if (contents.AsTriangles != null) return contents.AsTriangles;
 
-			var arr = AsUIntArray(ref contents, bufferViewData, offset);
-			for (var i = 0; i < arr.Length; i += 3)
-			{
-				var temp = arr[i];
-				arr[i] = arr[i + 2];
-				arr[i + 2] = temp;
-			}
+			contents.AsTriangles = AsUIntArray(ref contents, bufferViewData, offset);
 
-			contents.AsTriangles = arr;
-
-			return arr;
+			return contents.AsTriangles;
 		}
 
 		private static int GetDiscreteElement(byte[] bufferViewData, int offset, GLTFComponentType type)

diff --git a/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFComponent.cs b/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFComponent.cs
@@ -28,7 +28,7 @@ IEnumerator Start()
 			FileStream gltfStream = null;
 			if (UseStream)
 			{
-				var fullPath = Application.streamingAssetsPath + Url;
+				var fullPath = Path.Combine(Application.streamingAssetsPath, Url);
 				gltfStream = File.OpenRead(fullPath);
 				loader = new GLTFSceneImporter(
 					fullPath,

diff --git a/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFSceneExporter.cs b/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFSceneExporter.cs
@@ -303,19 +303,19 @@ private MeshPrimitive[] ExportPrimitive(GameObject gameObject)
 			AccessorId aPosition = null, aNormal = null, aTangent = null,
 				aTexcoord0 = null, aTexcoord1 = null, aColor0 = null;
 
-			aPosition = ExportAccessor(InvertZ(meshObj.vertices));
+			aPosition = ExportAccessor(GLTFUnityHelpers.FlipVectorArrayHandedness(meshObj.vertices));
 
 			if (meshObj.normals.Length != 0)
-				aNormal = ExportAccessor(InvertZ(meshObj.normals));
+				aNormal = ExportAccessor(GLTFUnityHelpers.FlipVectorArrayHandedness(meshObj.normals));
 
 			if (meshObj.tangents.Length != 0)
-				aTangent = ExportAccessor(InvertW(meshObj.tangents));
+				aTangent = ExportAccessor(GLTFUnityHelpers.FlipVectorArrayHandedness(meshObj.tangents));
 
 			if (meshObj.uv.Length != 0)
-				aTexcoord0 = ExportAccessor(FlipY(meshObj.uv));
+				aTexcoord0 = ExportAccessor(GLTFUnityHelpers.FlipTexCoordArrayV(meshObj.uv));
 
 			if (meshObj.uv2.Length != 0)
-				aTexcoord1 = ExportAccessor(FlipY(meshObj.uv2));
+				aTexcoord1 = ExportAccessor(GLTFUnityHelpers.FlipTexCoordArrayV(meshObj.uv2));
 
 			if (meshObj.colors.Length != 0)
 				aColor0 = ExportAccessor(meshObj.colors);
@@ -327,7 +327,7 @@ private MeshPrimitive[] ExportPrimitive(GameObject gameObject)
 				var primitive = new MeshPrimitive();
 
 				var triangles = meshObj.GetTriangles(submesh);
-				primitive.Indices = ExportAccessor(FlipFaces(triangles), true);
+				primitive.Indices = ExportAccessor(GLTFUnityHelpers.FlipFaces(triangles), true);
 
 				primitive.Attributes = new Dictionary<string, AccessorId>();
 				primitive.Attributes.Add(SemanticProperties.POSITION, aPosition);
@@ -728,48 +728,6 @@ private SamplerId ExportSampler(UnityEngine.Texture texture)
 			return samplerId;
 		}
 
-		private Vector2[] FlipY(Vector2[] arr)
-		{
-			var len = arr.Length;
-			for(var i = 0; i < len; i++)
-			{
-				arr[i].y = 1 - arr[i].y;
-			}
-			return arr;
-		}
-
-		private Vector3[] InvertZ(Vector3[] arr)
-		{
-			var len = arr.Length;
-			for(var i = 0; i < len; i++)
-			{
-				arr[i].z = -arr[i].z;
-			}
-			return arr;
-		}
-
-		private Vector4[] InvertW(Vector4[] arr)
-		{
-			var len = arr.Length;
-			for(var i = 0; i < len; i++)
-			{
-				arr[i].w = -arr[i].w;
-			}
-			return arr;
-		}
-
-		private int[] FlipFaces(int[] arr)
-		{
-			var triangles = new int[arr.Length];
-			for (int i = 0; i < arr.Length; i += 3)
-			{
-				triangles[i + 2] = arr[i];
-				triangles[i + 1] = arr[i + 1];
-				triangles[i] = arr[i + 2];
-			}
-			return triangles;
-		}
-
 		private AccessorId ExportAccessor(int[] arr, bool isIndices = false)
 		{
 			var count = arr.Length;

diff --git a/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFSceneImporter.cs b/UnityGLTF/Assets/UnityGLTF/Scripts/GLTFSceneImporter.cs
@@ -257,6 +257,43 @@ protected virtual void BuildMeshAttributes(MeshPrimitive primitive, int meshID,
 				}
 
 				GLTFHelpers.BuildMeshAttributes(ref attributeAccessors);
+
+				// Flip vectors and triangles to the Unity coordinate system.
+				if (attributeAccessors.ContainsKey(SemanticProperties.POSITION))
+				{
+					NumericArray resultArray = attributeAccessors[SemanticProperties.POSITION].AccessorContent;
+					resultArray.AsVertices = GLTFUnityHelpers.FlipVectorArrayHandedness(resultArray.AsVertices);
+					attributeAccessors[SemanticProperties.POSITION].AccessorContent = resultArray;
+				}
+				if (attributeAccessors.ContainsKey(SemanticProperties.INDICES))
+				{
+					NumericArray resultArray = attributeAccessors[SemanticProperties.INDICES].AccessorContent;
+					resultArray.AsTriangles = GLTFUnityHelpers.FlipFaces(resultArray.AsTriangles);
+					attributeAccessors[SemanticProperties.INDICES].AccessorContent = resultArray;
+				}
+				if (attributeAccessors.ContainsKey(SemanticProperties.NORMAL))
+				{
+					NumericArray resultArray = attributeAccessors[SemanticProperties.NORMAL].AccessorContent;
+					resultArray.AsNormals = GLTFUnityHelpers.FlipVectorArrayHandedness(resultArray.AsNormals);
+					attributeAccessors[SemanticProperties.NORMAL].AccessorContent = resultArray;
+				}
+				// TexCoord goes from 0 to 3 to match GLTFHelpers.BuildMeshAttributes
+				for (int i = 0; i < 4; i++)
+				{
+					if (attributeAccessors.ContainsKey(SemanticProperties.TexCoord(i)))
+					{
+						NumericArray resultArray = attributeAccessors[SemanticProperties.TexCoord(i)].AccessorContent;
+						resultArray.AsTexcoords = GLTFUnityHelpers.FlipTexCoordArrayV(resultArray.AsTexcoords);
+						attributeAccessors[SemanticProperties.TexCoord(i)].AccessorContent = resultArray;
+					}
+				}
+				if (attributeAccessors.ContainsKey(SemanticProperties.TANGENT))
+				{
+					NumericArray resultArray = attributeAccessors[SemanticProperties.TANGENT].AccessorContent;
+					resultArray.AsTangents = GLTFUnityHelpers.FlipVectorArrayHandedness(resultArray.AsTangents);
+					attributeAccessors[SemanticProperties.TANGENT].AccessorContent = resultArray;
+				}
+
 				_assetCache.MeshCache[meshID][primitiveIndex].MeshAttributes = attributeAccessors;
 			}
 		}