Box2D/Collision/b2BroadPhase.cpp

0001 /*
0002 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
0003 *
0004 * This software is provided 'as-is', without any express or implied
0005 * warranty.  In no event will the authors be held liable for any damages
0006 * arising from the use of this software.
0007 * Permission is granted to anyone to use this software for any purpose,
0008 * including commercial applications, and to alter it and redistribute it
0009 * freely, subject to the following restrictions:
0010 * 1. The origin of this software must not be misrepresented; you must not
0011 * claim that you wrote the original software. If you use this software
0012 * in a product, an acknowledgment in the product documentation would be
0013 * appreciated but is not required.
0014 * 2. Altered source versions must be plainly marked as such, and must not be
0015 * misrepresented as being the original software.
0016 * 3. This notice may not be removed or altered from any source distribution.
0017 */
0018
0019 #include <Box2D/Collision/b2BroadPhase.h>
0020
0021 b2BroadPhase::b2BroadPhase()
0022 {
0023     m_proxyCount = 0;
0024
0025     m_pairCapacity = 16;
0026     m_pairCount = 0;
0027     m_pairBuffer = (b2Pair*)b2Alloc(m_pairCapacity * sizeof(b2Pair));
0028
0029     m_moveCapacity = 16;
0030     m_moveCount = 0;
0031     m_moveBuffer = (int32*)b2Alloc(m_moveCapacity * sizeof(int32));
0032 }
0033
0034 b2BroadPhase::~b2BroadPhase()
0035 {
0036     b2Free(m_moveBuffer);
0037     b2Free(m_pairBuffer);
0038 }
0039
0040 int32 b2BroadPhase::CreateProxy(const b2AABB& aabb, void* userData)
0041 {
0042     int32 proxyId = m_tree.CreateProxy(aabb, userData);
0043     ++m_proxyCount;
0044     BufferMove(proxyId);
0045     return proxyId;
0046 }
0047
0048 void b2BroadPhase::DestroyProxy(int32 proxyId)
0049 {
0050     UnBufferMove(proxyId);
0051     --m_proxyCount;
0052     m_tree.DestroyProxy(proxyId);
0053 }
0054
0055 void b2BroadPhase::MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement)
0056 {
0057     bool buffer = m_tree.MoveProxy(proxyId, aabb, displacement);
0058     if (buffer)
0059     {
0060         BufferMove(proxyId);
0061     }
0062 }
0063
0064 void b2BroadPhase::TouchProxy(int32 proxyId)
0065 {
0066     BufferMove(proxyId);
0067 }
0068
0069 void b2BroadPhase::BufferMove(int32 proxyId)
0070 {
0071     if (m_moveCount == m_moveCapacity)
0072     {
0073         int32* oldBuffer = m_moveBuffer;
0074         m_moveCapacity *= 2;
0075         m_moveBuffer = (int32*)b2Alloc(m_moveCapacity * sizeof(int32));
0076         memcpy(m_moveBuffer, oldBuffer, m_moveCount * sizeof(int32));
0077         b2Free(oldBuffer);
0078     }
0079
0080     m_moveBuffer[m_moveCount] = proxyId;
0081     ++m_moveCount;
0082 }
0083
0084 void b2BroadPhase::UnBufferMove(int32 proxyId)
0085 {
0086     for (int32 i = 0; i < m_moveCount; ++i)
0087     {
0088         if (m_moveBuffer[i] == proxyId)
0089         {
0090             m_moveBuffer[i] = e_nullProxy;
0091         }
0092     }
0093 }
0094
0095 // This is called from b2DynamicTree::Query when we are gathering pairs.
0096 bool b2BroadPhase::QueryCallback(int32 proxyId)
0097 {
0098     // A proxy cannot form a pair with itself.
0099     if (proxyId == m_queryProxyId)
0100     {
0101         return true;
0102     }
0103
0104     // Grow the pair buffer as needed.
0105     if (m_pairCount == m_pairCapacity)
0106     {
0107         b2Pair* oldBuffer = m_pairBuffer;
0108         m_pairCapacity *= 2;
0109         m_pairBuffer = (b2Pair*)b2Alloc(m_pairCapacity * sizeof(b2Pair));
0110         memcpy(m_pairBuffer, oldBuffer, m_pairCount * sizeof(b2Pair));
0111         b2Free(oldBuffer);
0112     }
0113
0114     m_pairBuffer[m_pairCount].proxyIdA = b2Min(proxyId, m_queryProxyId);
0115     m_pairBuffer[m_pairCount].proxyIdB = b2Max(proxyId, m_queryProxyId);
0116     ++m_pairCount;
0117
0118     return true;
0119 }