fixes some isues with the gltfLoader when there are several skins

jme3-examples/src/main/java/jme3test/model/TestGltfLoading.java

@@ -109,6 +109,8 @@ public class TestGltfLoading extends SimpleApplication {
 //        rootNode.addLight(pl);
 //        PointLight pl1 = new PointLight(new Vector3f(-5.0f, -5.0f, -5.0f), ColorRGBA.White.mult(0.5f), 50);
 //        rootNode.addLight(pl1);
+
+        loadModel("Models/gltf/polly/project_polly.gltf", new Vector3f(0, 0, 0), 0.5f);
         //loadModel("Models/gltf/nier/scene.gltf", new Vector3f(0, -1.5f, 0), 0.01f);
         //loadModel("Models/gltf/izzy/scene.gltf", new Vector3f(0, -1, 0), 0.01f);
         //loadModel("Models/gltf/darth/scene.gltf", new Vector3f(0, -1, 0), 0.01f);
@@ -118,7 +120,7 @@ public class TestGltfLoading extends SimpleApplication {
         //loadModel("Models/gltf/war/scene.gltf", new Vector3f(0, -1, 0), 0.1f);
         //loadModel("Models/gltf/ganjaarl/scene.gltf", new Vector3f(0, -1, 0), 0.01f);
         //loadModel("Models/gltf/hero/scene.gltf", new Vector3f(0, -1, 0), 0.1f);
-        loadModel("Models/gltf/mercy/scene.gltf", new Vector3f(0, -1, 0), 0.01f);
+        ///    loadModel("Models/gltf/mercy/scene.gltf", new Vector3f(0, -1, 0), 0.01f);
         //loadModel("Models/gltf/crab/scene.gltf", Vector3f.ZERO, 1);
         //loadModel("Models/gltf/manta/scene.gltf", Vector3f.ZERO, 0.2f);
         //loadModel("Models/gltf/bone/scene.gltf", Vector3f.ZERO, 0.1f);
@@ -234,7 +236,7 @@ public class TestGltfLoading extends SimpleApplication {
         }
         //System.err.println(ctrl.getArmature().toString());
         //ctrl.setHardwareSkinningPreferred(false);
-        getStateManager().getState(ArmatureDebugAppState.class).addArmatureFrom(ctrl);
+        //     getStateManager().getState(ArmatureDebugAppState.class).addArmatureFrom(ctrl);
 //        AnimControl aCtrl = findControl(s, AnimControl.class);
 //        //ctrl.getSpatial().removeControl(ctrl);
 //        if (aCtrl == null) {

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

@@ -245,9 +245,11 @@ public class GltfLoader implements AssetLoader {
         Integer skinIndex = getAsInteger(nodeData, "skin");
         if (skinIndex != null) {
             SkinData skinData = fetchFromCache("skins", skinIndex, SkinData.class);
-            List<Spatial> spatials = skinnedSpatials.get(skinData);
-            spatials.add(spatial);
-            skinData.used = true;
+            if (skinData != null) {
+                List<Spatial> spatials = skinnedSpatials.get(skinData);
+                spatials.add(spatial);
+                skinData.used = true;
+            }
         }
 
         spatial.setLocalTransform(readTransforms(nodeData));
@@ -1027,19 +1029,21 @@ public class GltfLoader implements AssetLoader {
     private void setupControls() {
         for (SkinData skinData : skinnedSpatials.keySet()) {
             List<Spatial> spatials = skinnedSpatials.get(skinData);
-            Spatial spatial = skinData.parent;
             if (spatials.isEmpty()) {
                 continue;
             }
+            Spatial spatial = skinData.parent;
 
             if (spatials.size() >= 1) {
                 spatial = findCommonAncestor(spatials);
             }
 
-            if (skinData.parent != null && spatial != skinData.parent) {
-                skinData.rootBoneTransformOffset = spatial.getWorldTransform().invert();
-                skinData.rootBoneTransformOffset.combineWithParent(skinData.parent.getWorldTransform());
-            }
+//            if (spatial != skinData.parent) {
+//                skinData.rootBoneTransformOffset = spatial.getWorldTransform().invert();
+//                if (skinData.parent != null) {
+//                    skinData.rootBoneTransformOffset.combineWithParent(skinData.parent.getWorldTransform());
+//                }
+//            }
             
             if (skinData.animComposer != null && skinData.animComposer.getSpatial() == null) {
                 spatial.addControl(skinData.animComposer);