org.bytedeco.liquidfun

Class b2DynamicTree

java.lang.Object

org.bytedeco.javacpp.Pointer

org.bytedeco.liquidfun.b2DynamicTree

All Implemented Interfaces:

AutoCloseable

@NoOffset
 @Properties(inherit=liquidfun.class)
public class b2DynamicTree
extends Pointer

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.

Nested Class Summary

Nested classes/interfaces inherited from class org.bytedeco.javacpp.Pointer

Pointer.CustomDeallocator, Pointer.Deallocator, Pointer.NativeDeallocator

Field Summary

Fields inherited from class org.bytedeco.javacpp.Pointer

address, capacity, limit, position

Constructor Summary

Constructors

Constructor and Description
b2DynamicTree() Constructing the tree initializes the node pool.
b2DynamicTree(long size) Native array allocator.
b2DynamicTree(Pointer p) Pointer cast constructor.

Method Summary

Modifier and Type	Method and Description
int	CreateProxy(b2AABB aabb, Pointer userData) Create a proxy.
void	DestroyProxy(int proxyId) Destroy a proxy.
float	GetAreaRatio() Get the ratio of the sum of the node areas to the root area.
b2AABB	GetFatAABB(int proxyId) Get the fat AABB for a proxy.
int	GetHeight() Compute the height of the binary tree in O(N) time.
int	GetMaxBalance() Get the maximum balance of an node in the tree.
Pointer	GetUserData(int proxyId) Get proxy user data.
boolean	MoveProxy(int proxyId, b2AABB aabb1, b2Vec2 displacement) Move a proxy with a swepted AABB.
b2DynamicTree	position(long position)
void	Query(b2DynamicTreeQueryCallback callback, b2AABB aabb) Query an AABB for overlapping proxies.
void	RayCast(b2DynamicTreeRayCastCallback callback, b2RayCastInput input) Ray-cast against the proxies in the tree.
void	RebuildBottomUp() Build an optimal tree.
void	ShiftOrigin(b2Vec2 newOrigin) Shift the world origin.
void	Validate() Validate this tree.

Methods inherited from class org.bytedeco.javacpp.Pointer

address, asBuffer, asByteBuffer, availablePhysicalBytes, calloc, capacity, capacity, close, deallocate, deallocate, deallocateReferences, deallocator, deallocator, equals, fill, formatBytes, free, hashCode, isNull, limit, limit, malloc, maxBytes, maxPhysicalBytes, memchr, memcmp, memcpy, memmove, memset, offsetof, parseBytes, physicalBytes, position, put, realloc, setNull, sizeof, toString, totalBytes, totalPhysicalBytes, withDeallocator, zero

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

b2DynamicTree

public b2DynamicTree(Pointer p)

Pointer cast constructor. Invokes Pointer.Pointer(Pointer).

b2DynamicTree

public b2DynamicTree(long size)

Native array allocator. Access with Pointer.position(long).

b2DynamicTree

public b2DynamicTree()

Constructing the tree initializes the node pool.

Method Detail

position

public b2DynamicTree position(long position)

Overrides:

position in class Pointer

CreateProxy

@Cast(value="int32")
public int CreateProxy(@Const @ByRef
                                             b2AABB aabb,
                                             Pointer userData)

Create a proxy. Provide a tight fitting AABB and a userData pointer.

DestroyProxy

public void DestroyProxy(@Cast(value="int32")
                         int proxyId)

Destroy a proxy. This asserts if the id is invalid.

MoveProxy

@Cast(value="bool")
public boolean MoveProxy(@Cast(value="int32")
                                              int proxyId,
                                              @Const @ByRef
                                              b2AABB aabb1,
                                              @Const @ByRef
                                              b2Vec2 displacement)

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.

Returns:

true if the proxy was re-inserted.

GetUserData

public Pointer GetUserData(@Cast(value="int32")
                           int proxyId)

Get proxy user data.

Returns:

the proxy user data or 0 if the id is invalid.

GetFatAABB

@Const
 @ByRef
public b2AABB GetFatAABB(@Cast(value="int32")
                                          int proxyId)

Get the fat AABB for a proxy.

Query

public void Query(b2DynamicTreeQueryCallback callback,
                  @Const @ByRef
                  b2AABB aabb)

Query an AABB for overlapping proxies. The callback class is called for each proxy that overlaps the supplied AABB.

RayCast

public void RayCast(b2DynamicTreeRayCastCallback callback,
                    @Const @ByRef
                    b2RayCastInput input)

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:

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.

Validate

public void Validate()

Validate this tree. For testing.

GetHeight

@Cast(value="int32")
public int GetHeight()

Compute the height of the binary tree in O(N) time. Should not be called often.

GetMaxBalance

@Cast(value="int32")
public int GetMaxBalance()

Get the maximum balance of an node in the tree. The balance is the difference in height of the two children of a node.

GetAreaRatio

@Cast(value="float32")
public float GetAreaRatio()

Get the ratio of the sum of the node areas to the root area.

RebuildBottomUp

public void RebuildBottomUp()

Build an optimal tree. Very expensive. For testing.

ShiftOrigin

public void ShiftOrigin(@Const @ByRef
                        b2Vec2 newOrigin)

Shift the world origin. Useful for large worlds. The shift formula is: position -= newOrigin

Parameters:

newOrigin - the new origin with respect to the old origin