Merge pull request #16267 from takahirox/FixGLTFExporter

Fix GLTFExporter bug

Author: mrdoob

examples/js/exporters/GLTFExporter.js

@@ -123,6 +123,23 @@ THREE.GLTFExporter.prototype = {
 
 		var cachedCanvas;
 
+		var uids = new Map();
+		var uid = 0;
+
+		/**
+		 * Assign and return a temporal unique id for an object
+		 * especially which doesn't have .uuid
+		 * @param  {Object} object
+		 * @return {Integer}
+		 */
+		function getUID( object ) {
+
+			if ( ! uids.has( object ) ) uids.set( object, uid ++ );
+
+			return uids.get( object );
+
+		}
+
 		/**
 		 * Compare two arrays
 		 * @param  {Array} array1 Array 1 to compare
@@ -1175,9 +1192,9 @@ THREE.GLTFExporter.prototype = {
 
 				}
 
-				if ( cachedData.attributes.has( attribute ) ) {
+				if ( cachedData.attributes.has( getUID( attribute ) ) ) {
 
-					attributes[ attributeName ] = cachedData.attributes.get( attribute );
+					attributes[ attributeName ] = cachedData.attributes.get( getUID( attribute ) );
 					continue;
 
 				}
@@ -1198,7 +1215,7 @@ THREE.GLTFExporter.prototype = {
 				if ( accessor !== null ) {
 
 					attributes[ attributeName ] = accessor;
-					cachedData.attributes.set( attribute, accessor );
+					cachedData.attributes.set( getUID( attribute ), accessor );
 
 				}
 
@@ -1264,9 +1281,9 @@ THREE.GLTFExporter.prototype = {
 
 						var baseAttribute = geometry.attributes[ attributeName ];
 
-						if ( cachedData.attributes.has( attribute ) ) {
+						if ( cachedData.attributes.has( getUID( attribute ) ) ) {
 
-							target[ gltfAttributeName ] = cachedData.attributes.get( attribute );
+							target[ gltfAttributeName ] = cachedData.attributes.get( getUID( attribute ) );
 							continue;
 
 						}
@@ -1286,7 +1303,7 @@ THREE.GLTFExporter.prototype = {
 						}
 
 						target[ gltfAttributeName ] = processAccessor( relativeAttribute, geometry );
-						cachedData.attributes.set( baseAttribute, target[ gltfAttributeName ] );
+						cachedData.attributes.set( getUID( baseAttribute ), target[ gltfAttributeName ] );
 
 					}
 
@@ -1355,7 +1372,13 @@ THREE.GLTFExporter.prototype = {
 
 				if ( geometry.index !== null ) {
 
-					var cacheKey = geometry.uuid + ':' + groups[ i ].start + ':' + groups[ i ].count;
+					var cacheKey = getUID( geometry.index );
+
+					if ( groups[ i ].start !== undefined || groups[ i ].count !== undefined ) {
+
+						cacheKey += ':' + groups[ i ].start + ':' + groups[ i ].count;
+
+					}
 
 					if ( cachedData.attributes.has( cacheKey ) ) {