90 lines
2.1 KiB
C++
90 lines
2.1 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "UnionFind.h"
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#include <assert.h>
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#include <algorithm>
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UnionFind::~UnionFind()
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{
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Free();
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}
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UnionFind::UnionFind()
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:m_elements(0),
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m_N(0)
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{
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}
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void UnionFind::Allocate(int N)
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{
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if (m_N < N)
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{
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//Free(); //not necessary with stl vectors
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m_N = N;
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m_elements.resize(N);// = new Element[N];
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}
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}
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void UnionFind::Free()
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{
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if (m_N)
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{
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m_N=0;
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m_elements.clear();
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}
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}
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void UnionFind::reset(int N)
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{
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Allocate(N);
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for (int i = 0; i < m_N; i++)
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{
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m_elements[i].m_id = i; m_elements[i].m_sz = 1;
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}
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}
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bool UnionFindElementSortPredicate(const Element& lhs, const Element& rhs)
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{
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return lhs.m_id < rhs.m_id;
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}
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///this is a special operation, destroying the content of UnionFind.
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///it sorts the elements, based on island id, in order to make it easy to iterate over islands
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void UnionFind::sortIslands()
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{
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//first store the original body index, and islandId
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int numElements = m_elements.size();
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for (int i=0;i<numElements;i++)
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{
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m_elements[i].m_id = find(i);
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m_elements[i].m_sz = i;
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}
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// Sort the vector using predicate and std::sort
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std::sort(m_elements.begin(), m_elements.end(), UnionFindElementSortPredicate);
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}
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