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Box2D
2.3.0
A 2D Physics Engine for Games
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#include <b2DynamicTree.h>
Public Member Functions | |
| b2DynamicTree () | |
| Constructing the tree initializes the node pool. | |
| ~b2DynamicTree () | |
| Destroy the tree, freeing the node pool. | |
| int32 | CreateProxy (const b2AABB &aabb, void *userData) |
| Create a proxy. Provide a tight fitting AABB and a userData pointer. | |
| void | DestroyProxy (int32 proxyId) |
| Destroy a proxy. This asserts if the id is invalid. | |
| bool | MoveProxy (int32 proxyId, const b2AABB &aabb1, const b2Vec2 &displacement) |
| void * | GetUserData (int32 proxyId) const |
| const b2AABB & | GetFatAABB (int32 proxyId) const |
| Get the fat AABB for a proxy. | |
| template<typename T > | |
| void | Query (T *callback, const b2AABB &aabb) const |
| template<typename T > | |
| void | RayCast (T *callback, const b2RayCastInput &input) const |
| void | Validate () const |
| Validate this tree. For testing. | |
| int32 | GetHeight () const |
| int32 | GetMaxBalance () const |
| float32 | GetAreaRatio () const |
| Get the ratio of the sum of the node areas to the root area. | |
| void | RebuildBottomUp () |
| Build an optimal tree. Very expensive. For testing. | |
| void | ShiftOrigin (const b2Vec2 &newOrigin) |
A dynamic AABB tree broad-phase, inspired by Nathanael Presson's btDbvt. 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 and relocatable, so we use node indices rather than pointers.
| int32 b2DynamicTree::GetHeight | ( | ) | const |
Compute the height of the binary tree in O(N) time. Should not be called often.
| int32 b2DynamicTree::GetMaxBalance | ( | ) | const |
Get the maximum balance of an node in the tree. The balance is the difference in height of the two children of a node.
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Get proxy user data.
Move a proxy with a swepted 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.
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inline |
Query an AABB for overlapping proxies. The callback class is called for each proxy that overlaps the supplied AABB.
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inline |
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.
| input | the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1). |
| callback | a callback class that is called for each proxy that is hit by the ray. |
| void b2DynamicTree::ShiftOrigin | ( | const b2Vec2 & | newOrigin | ) |
Shift the world origin. Useful for large worlds. The shift formula is: position -= newOrigin
| newOrigin | the new origin with respect to the old origin |
1.8.14