public World( Vector2 gravity )
{
island = new Island();
enabled = true;
controllerList = new List<Controller>();
breakableBodyList = new List<BreakableBody>();
bodyList = new List<Body>( 32 );
jointList = new List<Joint>( 32 );
#if USE_AWAKE_BODY_SET
AwakeBodySet = new HashSet<Body>();
AwakeBodyList = new List<Body>(32);
#endif
#if USE_ISLAND_SET
IslandSet = new HashSet<Body>();
#endif
#if OPTIMIZE_TOI
TOISet = new HashSet<Body>();
#endif
_queryAABBCallbackWrapper = queryAABBCallbackWrapper;
_rayCastCallbackWrapper = rayCastCallbackWrapper;
contactManager = new ContactManager( new DynamicTreeBroadPhase() );
this.gravity = gravity;
}