btUnionFind.cpp

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00001 /*
00002 Bullet Continuous Collision Detection and Physics Library
00003 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/
00004 
00005 This software is provided 'as-is', without any express or implied warranty.
00006 In no event will the authors be held liable for any damages arising from the use of this software.
00007 Permission is granted to anyone to use this software for any purpose, 
00008 including commercial applications, and to alter it and redistribute it freely, 
00009 subject to the following restrictions:
00010 
00011 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
00012 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
00013 3. This notice may not be removed or altered from any source distribution.
00014 */
00015 
00016 #include "btUnionFind.h"
00017 
00018 
00019 
00020 btUnionFind::~btUnionFind()
00021 {
00022         Free();
00023 
00024 }
00025 
00026 btUnionFind::btUnionFind()
00027 { 
00028 
00029 }
00030 
00031 void    btUnionFind::allocate(int N)
00032 {
00033         m_elements.resize(N);
00034 }
00035 void    btUnionFind::Free()
00036 {
00037         m_elements.clear();
00038 }
00039 
00040 
00041 void    btUnionFind::reset(int N)
00042 {
00043         allocate(N);
00044 
00045         for (int i = 0; i < N; i++) 
00046         { 
00047                 m_elements[i].m_id = i; m_elements[i].m_sz = 1; 
00048         } 
00049 }
00050 
00051 
00052 class btUnionFindElementSortPredicate
00053 {
00054         public:
00055 
00056                 bool operator() ( const btElement& lhs, const btElement& rhs ) const
00057                 {
00058                         return lhs.m_id < rhs.m_id;
00059                 }
00060 };
00061 
00064 void    btUnionFind::sortIslands()
00065 {
00066 
00067         //first store the original body index, and islandId
00068         int numElements = m_elements.size();
00069         
00070         for (int i=0;i<numElements;i++)
00071         {
00072                 m_elements[i].m_id = find(i);
00073 #ifndef STATIC_SIMULATION_ISLAND_OPTIMIZATION
00074                 m_elements[i].m_sz = i;
00075 #endif //STATIC_SIMULATION_ISLAND_OPTIMIZATION
00076         }
00077         
00078          // Sort the vector using predicate and std::sort
00079           //std::sort(m_elements.begin(), m_elements.end(), btUnionFindElementSortPredicate);
00080           m_elements.quickSort(btUnionFindElementSortPredicate());
00081 
00082 }