controls: Don't make scene graph assumptions when setting the CollisionRay's height

direct/src/controls/GravityWalker.py

@@ -179,9 +179,9 @@ class GravityWalker(DirectObject.DirectObject):
         # a higher or lower value depending on whether you want an avatar
         # that is outside of the world to step up to the floor when they
         # get under valid floor:
-        cRay = CollisionRay(0.0, 0.0, CollisionHandlerRayStart, 0.0, 0.0, -1.0)
+        self.cRay = CollisionRay(0.0, 0.0, CollisionHandlerRayStart, 0.0, 0.0, -1.0)
         cRayNode = CollisionNode('GW.cRayNode')
-        cRayNode.addSolid(cRay)
+        cRayNode.addSolid(self.cRay)
         self.cRayNodePath = self.avatarNodePath.attachNewNode(cRayNode)
         cRayNode.setFromCollideMask(bitmask)
         cRayNode.setIntoCollideMask(BitMask32.allOff())
@@ -697,8 +697,4 @@ class GravityWalker(DirectObject.DirectObject):
     # There are sometimes issues if the collision ray height is
     # so tall that it collides with multiple levels of floors.
     def setCollisionRayHeight(self, height):
-        oldNode = self.avatarNodePath.getNode(0)
-        cRayNode = oldNode.getChild(2)
-        cRayNode.removeSolid(0)
-        cRay = CollisionRay(0.0, 0.0, height, 0.0, 0.0, -1.0)
-        cRayNode.addSolid(cRay)        
+        self.cRay.setOrigin(0.0, 0.0, height)