A dynamic tree arranges data in a binary tree to accelerate
queries such as volume queries and ray casts. Leafs are proxies
with an AABB. In the tree we expand the proxy AABB by b2_fatAABBFactor
so that the proxy AABB is bigger than the client object. This allows the client
object to move by small amounts without triggering a tree update.
Nodes are pooled.
public function b2DynamicTree()
Constructing the tree initializes the node pool.
public function CreateProxy(aabb:b2AABB, userData:*):b2DynamicTreeNode
Create a proxy. Provide a tight fitting AABB and a userData.
Parameters
Returns
public function DestroyProxy(proxy:b2DynamicTreeNode):void
Destroy a proxy. This asserts if the id is invalid.
Parameters
public function GetFatAABB(proxy:b2DynamicTreeNode):b2AABBParameters
Returns
public function GetUserData(proxy:b2DynamicTreeNode):*
Get user data from a proxy. Returns null if the proxy is invalid.
Parameters
Returns
public function MoveProxy(proxy:b2DynamicTreeNode, aabb:b2AABB, displacement:b2Vec2):Boolean
Move a proxy with a swept AABB. If the proxy has moved outside of its fattened AABB,
then the proxy is removed from the tree and re-inserted. Otherwise
the function returns immediately.
Parameters
Returns
public function Query(callback:Function, aabb:b2AABB):void
Query an AABB for overlapping proxies. The callback
is called for each proxy that overlaps the supplied AABB.
The callback should match function signature
fuction callback(proxy:b2DynamicTreeNode):Boolean
and should return false to trigger premature termination.
Parameters
public function RayCast(callback:Function, input:b2RayCastInput):void
Ray-cast against the proxies in the tree. This relies on the callback
to perform a exact ray-cast in the case were the proxy contains a shape.
The callback also performs the any collision filtering. This has performance
roughly equal to k log(n), where k is the number of collisions and n is the
number of proxies in the tree.
Parameters
| callback:Function — the ray-cast input data. The ray extends from p1 to p1 + maxFraction (p2 - p1).
|
| |
| input:b2RayCastInput — a callback class that is called for each proxy that is hit by the ray.
It should be of signature:
function callback(input:b2RayCastInput, proxy::void
|
public function Rebalance(iterations:int):void
Perform some iterations to re-balance the tree.
Parameters
Box2DFlash 2.1a
