Preserve all glTF joint attachments

jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/GltfLoader.java

@@ -1448,7 +1448,7 @@ private void findChildren(int nodeIndex) throws IOException {
                     // removing the spatial from the dummy node,
                     // it will be attached to the attachment node of the bone
                     s.removeFromParent();
-                    jw.attachedSpatial = s;
+                    jw.attachedSpatials.add(s);
                 }
             }
         }
@@ -1482,7 +1482,7 @@ private void setupControls() {
 
         for (int i = 0; i < nodes.size(); i++) {
             JointWrapper bw = fetchFromCache("nodes", i, JointWrapper.class);
-            if (bw == null || bw.attachedSpatial == null) {
+            if (bw == null || bw.attachedSpatials.isEmpty()) {
                 continue;
             }
             String jointName = bw.joint.getName();
@@ -1494,7 +1494,10 @@ private void setupControls() {
                         jointName);
                 rootNode.addControl(skinControl);
             }
-            skinControl.getAttachmentsNode(jointName).attachChild(bw.attachedSpatial);
+            Node attachmentNode = skinControl.getAttachmentsNode(jointName);
+            for (Spatial attachedSpatial : bw.attachedSpatials) {
+                attachmentNode.attachChild(attachedSpatial);
+            }
         }
     }
 
@@ -1597,7 +1600,7 @@ private class JointWrapper {
         int jointIndex;
         int skinIndex;
         boolean isRoot = false;
-        Spatial attachedSpatial;
+        List<Spatial> attachedSpatials = new ArrayList<>();
         List<Integer> children = new ArrayList<>();
 
         public JointWrapper(Joint joint, int jointIndex, int skinIndex) {

jme3-plugins/src/test/java/com/jme3/scene/plugins/gltf/GltfLoaderTest.java

@@ -74,6 +74,18 @@ public void init() {
 
     }
 
+    @Test
+    public void keepsEverySpatialAttachedToTheSameJoint() {
+        Spatial scene = assetManager.loadModel("gltf/JointAttachments.gltf");
+        boolean[] found = new boolean[2];
+        scene.depthFirstTraversal(spatial -> {
+            if ("FirstAttachment".equals(spatial.getName())) found[0] = true;
+            if ("SecondAttachment".equals(spatial.getName())) found[1] = true;
+        });
+        Assertions.assertTrue(found[0], "First joint attachment was lost");
+        Assertions.assertTrue(found[1], "Second joint attachment was lost");
+    }
+
     @Test
     public void testLoad() {
         Spatial scene = assetManager.loadModel("gltf/box/box.gltf");

jme3-plugins/src/test/resources/gltf/JointAttachments.gltf

@@ -0,0 +1,25 @@
+{
+  "asset": {"version": "2.0"},
+  "scene": 0,
+  "scenes": [{"nodes": [0]}],
+  "nodes": [
+    {"name": "Root", "children": [1, 2]},
+    {"name": "SkinnedMesh", "mesh": 0, "skin": 0},
+    {"name": "Joint", "children": [3, 4]},
+    {"name": "FirstAttachment"},
+    {"name": "SecondAttachment"}
+  ],
+  "skins": [{"joints": [2]}],
+  "meshes": [{"primitives": [{"attributes": {"POSITION": 0, "JOINTS_0": 1, "WEIGHTS_0": 2}}]}],
+  "buffers": [{"byteLength": 96, "uri": "data:application/octet-stream;base64,AAAAAAAAAAAAAAAAAACAPwAAAAAAAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAAAAAACAPwAAAAAAAAAAAAAAAAAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAAAA"}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 36},
+    {"buffer": 0, "byteOffset": 36, "byteLength": 12},
+    {"buffer": 0, "byteOffset": 48, "byteLength": 48}
+  ],
+  "accessors": [
+    {"bufferView": 0, "componentType": 5126, "count": 3, "type": "VEC3", "min": [0, 0, 0], "max": [1, 1, 0]},
+    {"bufferView": 1, "componentType": 5121, "count": 3, "type": "VEC4"},
+    {"bufferView": 2, "componentType": 5126, "count": 3, "type": "VEC4"}
+  ]
+}