Fix #2510 Incorrect gltf texture export when embedding is off

lib/GLTFExporter.js

@@ -762,7 +762,7 @@ GLTFExporter.prototype = {
 		 * @param  {Boolean} flipY before writing out the image
 		 * @return {Integer}     Index of the processed texture in the "images" array
 		 */
-		function processImage( image, format, flipY ) {
+		function processImage( image, format, flipY, bb_texture ) {
 
 			if ( ! cachedData.images.has( image ) ) {
 
@@ -838,8 +838,9 @@ GLTFExporter.prototype = {
 				}
 
 			} else {
-
-				gltfImage.uri = image.src;
+
+				gltfImage.name = bb_texture ? bb_texture.name : 'Unknown';
+				gltfImage.uri = bb_texture ? `${bb_texture.name.replace(/\.png$/, '')}.png` : '';
 
 			}
 
@@ -899,10 +900,12 @@ GLTFExporter.prototype = {
 
 			}
 
+			let bb_texture = Texture.all.find(tex => tex.getMaterial()?.map?.uuid == map.uuid);
+
 			var gltfTexture = {
 
 				sampler: processSampler( map ),
-				source: processImage( map.image, map.format, false )
+				source: processImage( map.image, map.format, false, bb_texture )
 
 			};