Bugfix: avoiding infinite loops while applying constraints.

jme3-blender/src/main/java/com/jme3/scene/plugins/blender/constraints/SimulationNode.java

@@ -7,6 +7,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.Stack;
 import java.util.logging.Logger;
 
 import com.jme3.animation.AnimChannel;
@@ -209,7 +210,6 @@ public class SimulationNode {
             TempVars vars = TempVars.get();
             AnimChannel animChannel = animControl.createChannel();
 
-            // List<Bone> bonesWithConstraints = this.collectBonesWithConstraints(skeleton);
             for (Animation animation : animations) {
                 float[] animationTimeBoundaries = this.computeAnimationTimeBoundaries(animation);
                 int maxFrame = (int) animationTimeBoundaries[0];
@@ -233,7 +233,7 @@ public class SimulationNode {
                     for (Bone rootBone : skeleton.getRoots()) {
                         // ignore the 0-indexed bone
                         if (skeleton.getBoneIndex(rootBone) > 0) {
-                            this.applyConstraints(rootBone, alteredOmas, applied, frame);
+                            this.applyConstraints(rootBone, alteredOmas, applied, frame, new Stack<Bone>());
                         }
                     }
 
@@ -294,18 +294,21 @@ public class SimulationNode {
      *            the set of OMAS of the altered bones (is populated if necessary)
      * @param frame
      *            the current frame of the animation
+     * @param bonesStack
+     *            the stack of bones used to avoid infinite loops while applying constraints
      */
-    private void applyConstraints(Bone bone, Set<Long> alteredOmas, Set<Long> applied, int frame) {
+    private void applyConstraints(Bone bone, Set<Long> alteredOmas, Set<Long> applied, int frame, Stack<Bone> bonesStack) {
+        if (!bonesStack.contains(bone)) {
+            bonesStack.push(bone);
             BoneContext boneContext = blenderContext.getBoneContext(bone);
             if (!applied.contains(boneContext.getBoneOma())) {
                 List<Constraint> constraints = this.findConstraints(boneContext.getBoneOma(), blenderContext);
                 if (constraints != null && constraints.size() > 0) {
-                // TODO: BEWARE OF INFINITE LOOPS !!!!!!!!!!!!!!!!!!!!!!!!!!
                     for (Constraint constraint : constraints) {
                         if (constraint.getTargetOMA() != null && constraint.getTargetOMA() > 0L) {
                             // first apply constraints of the target bone
                             BoneContext targetBone = blenderContext.getBoneContext(constraint.getTargetOMA());
-                        this.applyConstraints(targetBone.getBone(), alteredOmas, applied, frame);
+                            this.applyConstraints(targetBone.getBone(), alteredOmas, applied, frame, bonesStack);
                         }
                         constraint.apply(frame);
                         if (constraint.getAlteredOmas() != null) {
@@ -320,9 +323,11 @@ public class SimulationNode {
             List<Bone> children = bone.getChildren();
             if (children != null && children.size() > 0) {
                 for (Bone child : bone.getChildren()) {
-                this.applyConstraints(child, alteredOmas, applied, frame);
+                    this.applyConstraints(child, alteredOmas, applied, frame, bonesStack);
                 }
             }
+            bonesStack.pop();
+        }
     }
 
     /**