Only resolve our hand collisions that would not move the other avatar.

This helps us only penetrate the moveable parts of other avatars.

interface/src/avatar/Avatar.cpp

@@ -443,9 +443,16 @@ float Avatar::getHeight() const {
     return extents.maximum.y - extents.minimum.y;
 }
 
-bool Avatar::poke(ModelCollisionInfo& collision) {
-    // ATM poke() can only affect the Skeleton (not the head)
+bool Avatar::isPokeable(ModelCollisionInfo& collision) const {
+    // ATM only the Skeleton is pokeable
     // TODO: make poke affect head
+    if (collision._model == &_skeletonModel && collision._jointIndex != -1) {
+        return _skeletonModel.isPokeable(collision);
+    }
+    return false;
+}
+
+bool Avatar::poke(ModelCollisionInfo& collision) {
     if (collision._model == &_skeletonModel && collision._jointIndex != -1) {
         return _skeletonModel.poke(collision);
     }

interface/src/avatar/Avatar.h

@@ -128,6 +128,9 @@ public:
 
     float getHeight() const;
 
+    /// \return true if we expect the avatar would move as a result of the collision
+    bool isPokeable(ModelCollisionInfo& collision) const;
+
     /// \param collision a data structure for storing info about collisions against Models
     /// \return true if the collision affects the Avatar models
     bool poke(ModelCollisionInfo& collision);

interface/src/avatar/Hand.cpp

@@ -224,7 +224,8 @@ void Hand::updateCollisions() {
                 }
                 if (avatar->findSphereCollisions(palm.getPosition(), scaledPalmRadius, collisions)) {
                     for (int j = 0; j < collisions.size(); ++j) {
-                        if (!avatar->poke(collisions[j])) {
+                        // we don't resolve penetrations that would poke the other avatar
+                        if (!avatar->isPokeable(collisions[j])) {
                             totalPenetration = addPenetrations(totalPenetration, collisions[j]._penetration);
                         }
                     }

interface/src/renderer/Model.cpp

@@ -713,6 +713,20 @@ void Model::renderCollisionProxies(float alpha) {
     glPopMatrix();
 }
 
+bool Model::isPokeable(ModelCollisionInfo& collision) const {
+    // the joint is pokable by a collision if it exists and is free to move
+    const FBXJoint& joint = _geometry->getFBXGeometry().joints[collision._jointIndex];
+    if (joint.parentIndex == -1  || 
+        _jointStates.isEmpty())
+    {
+        return false;
+    }
+    // an empty freeLineage means the joint can't move
+    const FBXGeometry& geometry = _geometry->getFBXGeometry();
+    const QVector<int>& freeLineage = geometry.joints.at(collision._jointIndex).freeLineage;
+    return !freeLineage.isEmpty();
+}
+
 bool Model::poke(ModelCollisionInfo& collision) {
     // This needs work.  At the moment it can wiggle joints that are free to move (such as arms)
     // but unmovable joints (such as torso) cannot be influenced at all.

interface/src/renderer/Model.h

@@ -164,6 +164,9 @@ public:
     
     void renderCollisionProxies(float alpha);
 
+    /// \return true if the collision would move the model
+    bool isPokeable(ModelCollisionInfo& collision) const;
+
     /// \param collisionInfo info about the collision
     /// \return true if collision affects the Model
     bool poke(ModelCollisionInfo& collisionInfo);