public void removeCollisionObject(PhysicsCollisionObject obj) {
if (obj instanceof PhysicsGhostObject) {
removeGhostObject((PhysicsGhostObject) obj);
} else if (obj instanceof PhysicsRigidBody) {
removeRigidBody((PhysicsRigidBody) obj);
} else if (obj instanceof PhysicsCharacter) {
removeCharacter((PhysicsCharacter) obj);
}
}
