Box2D 2.3.0 A 2D Physics Engine for Games

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b2BroadPhase.h
1 /*
2 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
3 *
4 * This software is provided 'as-is', without any express or implied
5 * warranty. In no event will the authors be held liable for any damages
6 * arising from the use of this software.
7 * Permission is granted to anyone to use this software for any purpose,
8 * including commercial applications, and to alter it and redistribute it
9 * freely, subject to the following restrictions:
10 * 1. The origin of this software must not be misrepresented; you must not
11 * claim that you wrote the original software. If you use this software
12 * in a product, an acknowledgment in the product documentation would be
13 * appreciated but is not required.
14 * 2. Altered source versions must be plainly marked as such, and must not be
15 * misrepresented as being the original software.
16 * 3. This notice may not be removed or altered from any source distribution.
17 */
18
19 #ifndef B2_BROAD_PHASE_H
20 #define B2_BROAD_PHASE_H
21
22 #include <Box2D/Common/b2Settings.h>
23 #include <Box2D/Collision/b2Collision.h>
24 #include <Box2D/Collision/b2DynamicTree.h>
25 #include <algorithm>
26
27 struct b2Pair
28 {
29 int32 proxyIdA;
30 int32 proxyIdB;
31 };
32
36 class b2BroadPhase
37 {
38 public:
39
40 enum
41 {
42 e_nullProxy = -1
43 };
44
45 b2BroadPhase();
46 ~b2BroadPhase();
47
50 int32 CreateProxy(const b2AABB& aabb, void* userData);
51
53 void DestroyProxy(int32 proxyId);
54
57 void MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement);
58
60 void TouchProxy(int32 proxyId);
61
63 const b2AABB& GetFatAABB(int32 proxyId) const;
64
66 void* GetUserData(int32 proxyId) const;
67
69 bool TestOverlap(int32 proxyIdA, int32 proxyIdB) const;
70
72 int32 GetProxyCount() const;
73
75 template <typename T>
76 void UpdatePairs(T* callback);
77
80 template <typename T>
81 void Query(T* callback, const b2AABB& aabb) const;
82
90 template <typename T>
91 void RayCast(T* callback, const b2RayCastInput& input) const;
92
94 int32 GetTreeHeight() const;
95
97 int32 GetTreeBalance() const;
98
100 float32 GetTreeQuality() const;
101
105 void ShiftOrigin(const b2Vec2& newOrigin);
106
107 private:
108
109 friend class b2DynamicTree;
110
111 void BufferMove(int32 proxyId);
112 void UnBufferMove(int32 proxyId);
113
114 bool QueryCallback(int32 proxyId);
115
116 b2DynamicTree m_tree;
117
118 int32 m_proxyCount;
119
120 int32* m_moveBuffer;
121 int32 m_moveCapacity;
122 int32 m_moveCount;
123
124 b2Pair* m_pairBuffer;
125 int32 m_pairCapacity;
126 int32 m_pairCount;
127
128 int32 m_queryProxyId;
129 };
130
132 inline bool b2PairLessThan(const b2Pair& pair1, const b2Pair& pair2)
133 {
134 if (pair1.proxyIdA < pair2.proxyIdA)
135 {
136 return true;
137 }
138
139 if (pair1.proxyIdA == pair2.proxyIdA)
140 {
141 return pair1.proxyIdB < pair2.proxyIdB;
142 }
143
144 return false;
145 }
146
147 inline void* b2BroadPhase::GetUserData(int32 proxyId) const
148 {
149 return m_tree.GetUserData(proxyId);
150 }
151
152 inline bool b2BroadPhase::TestOverlap(int32 proxyIdA, int32 proxyIdB) const
153 {
154 const b2AABB& aabbA = m_tree.GetFatAABB(proxyIdA);
155 const b2AABB& aabbB = m_tree.GetFatAABB(proxyIdB);
156 return b2TestOverlap(aabbA, aabbB);
157 }
158
159 inline const b2AABB& b2BroadPhase::GetFatAABB(int32 proxyId) const
160 {
161 return m_tree.GetFatAABB(proxyId);
162 }
163
164 inline int32 b2BroadPhase::GetProxyCount() const
165 {
166 return m_proxyCount;
167 }
168
169 inline int32 b2BroadPhase::GetTreeHeight() const
170 {
171 return m_tree.GetHeight();
172 }
173
174 inline int32 b2BroadPhase::GetTreeBalance() const
175 {
176 return m_tree.GetMaxBalance();
177 }
178
179 inline float32 b2BroadPhase::GetTreeQuality() const
180 {
181 return m_tree.GetAreaRatio();
182 }
183
184 template <typename T>
185 void b2BroadPhase::UpdatePairs(T* callback)
186 {
187 // Reset pair buffer
188 m_pairCount = 0;
189
190 // Perform tree queries for all moving proxies.
191 for (int32 i = 0; i < m_moveCount; ++i)
192 {
193 m_queryProxyId = m_moveBuffer[i];
194 if (m_queryProxyId == e_nullProxy)
195 {
196 continue;
197 }
198
199 // We have to query the tree with the fat AABB so that
200 // we don't fail to create a pair that may touch later.
201 const b2AABB& fatAABB = m_tree.GetFatAABB(m_queryProxyId);
202
203 // Query tree, create pairs and add them pair buffer.
204 m_tree.Query(this, fatAABB);
205 }
206
207 // Reset move buffer
208 m_moveCount = 0;
209
210 // Sort the pair buffer to expose duplicates.
211 std::sort(m_pairBuffer, m_pairBuffer + m_pairCount, b2PairLessThan);
212
213 // Send the pairs back to the client.
214 int32 i = 0;
215 while (i < m_pairCount)
216 {
217 b2Pair* primaryPair = m_pairBuffer + i;
218 void* userDataA = m_tree.GetUserData(primaryPair->proxyIdA);
219 void* userDataB = m_tree.GetUserData(primaryPair->proxyIdB);
220
221 callback->AddPair(userDataA, userDataB);
222 ++i;
223
224 // Skip any duplicate pairs.
225 while (i < m_pairCount)
226 {
227 b2Pair* pair = m_pairBuffer + i;
228 if (pair->proxyIdA != primaryPair->proxyIdA || pair->proxyIdB != primaryPair->proxyIdB)
229 {
230 break;
231 }
232 ++i;
233 }
234 }
235
236 // Try to keep the tree balanced.
237 //m_tree.Rebalance(4);
238 }
239
240 template <typename T>
241 inline void b2BroadPhase::Query(T* callback, const b2AABB& aabb) const
242 {
243 m_tree.Query(callback, aabb);
244 }
245
246 template <typename T>
247 inline void b2BroadPhase::RayCast(T* callback, const b2RayCastInput& input) const
248 {
249 m_tree.RayCast(callback, input);
250 }
251
252 inline void b2BroadPhase::ShiftOrigin(const b2Vec2& newOrigin)
253 {
254 m_tree.ShiftOrigin(newOrigin);
255 }
256
257 #endif
b2BroadPhase::CreateProxy
int32 CreateProxy(const b2AABB &aabb, void *userData)
Definition: b2BroadPhase.cpp:40
b2DynamicTree
Definition: b2DynamicTree.h:61
b2DynamicTree::RayCast
void RayCast(T *callback, const b2RayCastInput &input) const
Definition: b2DynamicTree.h:204
b2BroadPhase
Definition: b2BroadPhase.h:36
b2BroadPhase::MoveProxy
void MoveProxy(int32 proxyId, const b2AABB &aabb, const b2Vec2 &displacement)
Definition: b2BroadPhase.cpp:55
b2BroadPhase::TestOverlap
bool TestOverlap(int32 proxyIdA, int32 proxyIdB) const
Test overlap of fat AABBs.
Definition: b2BroadPhase.h:152
b2DynamicTree::GetHeight
int32 GetHeight() const
Definition: b2DynamicTree.cpp:520
b2BroadPhase::GetTreeBalance
int32 GetTreeBalance() const
Get the balance of the embedded tree.
Definition: b2BroadPhase.h:174
b2Collision.h
b2BroadPhase::TouchProxy
void TouchProxy(int32 proxyId)
Call to trigger a re-processing of it&#39;s pairs on the next call to UpdatePairs.
Definition: b2BroadPhase.cpp:64
b2DynamicTree::ShiftOrigin
void ShiftOrigin(const b2Vec2 &newOrigin)
Definition: b2DynamicTree.cpp:770
b2DynamicTree::GetAreaRatio
float32 GetAreaRatio() const
Get the ratio of the sum of the node areas to the root area.
Definition: b2DynamicTree.cpp:531
b2BroadPhase::UpdatePairs
void UpdatePairs(T *callback)
Update the pairs. This results in pair callbacks. This can only add pairs.
Definition: b2BroadPhase.h:185
b2AABB
An axis aligned bounding box.
Definition: b2Collision.h:162
b2DynamicTree::GetUserData
void * GetUserData(int32 proxyId) const
Definition: b2DynamicTree.h:156
b2BroadPhase::DestroyProxy
void DestroyProxy(int32 proxyId)
Destroy a proxy. It is up to the client to remove any pairs.
Definition: b2BroadPhase.cpp:48
b2TestOverlap
bool b2TestOverlap(const b2Shape *shapeA, int32 indexA, const b2Shape *shapeB, int32 indexB, const b2Transform &xfA, const b2Transform &xfB)
Determine if two generic shapes overlap.
Definition: b2Collision.cpp:233
b2BroadPhase::ShiftOrigin
void ShiftOrigin(const b2Vec2 &newOrigin)
Definition: b2BroadPhase.h:252
b2BroadPhase::GetUserData
void * GetUserData(int32 proxyId) const
Get user data from a proxy. Returns NULL if the id is invalid.
Definition: b2BroadPhase.h:147
b2RayCastInput
Ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
Definition: b2Collision.h:147
b2DynamicTree::Query
void Query(T *callback, const b2AABB &aabb) const
Definition: b2DynamicTree.h:169
b2BroadPhase::GetTreeQuality
float32 GetTreeQuality() const
Get the quality metric of the embedded tree.
Definition: b2BroadPhase.h:179
b2BroadPhase::GetTreeHeight
int32 GetTreeHeight() const
Get the height of the embedded tree.
Definition: b2BroadPhase.h:169
b2DynamicTree::GetMaxBalance
int32 GetMaxBalance() const
Definition: b2DynamicTree.cpp:672
b2BroadPhase::RayCast
void RayCast(T *callback, const b2RayCastInput &input) const
Definition: b2BroadPhase.h:247
b2BroadPhase::Query
void Query(T *callback, const b2AABB &aabb) const
Definition: b2BroadPhase.h:241
b2Settings.h
b2Pair
Definition: b2BroadPhase.h:27
b2BroadPhase::GetProxyCount
int32 GetProxyCount() const
Get the number of proxies.
Definition: b2BroadPhase.h:164
b2Vec2
A 2D column vector.
Definition: b2Math.h:53
b2BroadPhase::GetFatAABB
const b2AABB & GetFatAABB(int32 proxyId) const
Get the fat AABB for a proxy.
Definition: b2BroadPhase.h:159
b2DynamicTree::GetFatAABB
const b2AABB & GetFatAABB(int32 proxyId) const
Get the fat AABB for a proxy.
Definition: b2DynamicTree.h:162