83 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			83 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 "btUnionFind.h"
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btUnionFind::~btUnionFind()
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{
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	Free();
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}
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btUnionFind::btUnionFind()
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{ 
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}
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void	btUnionFind::allocate(int N)
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{
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	m_elements.resize(N);
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}
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void	btUnionFind::Free()
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{
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	m_elements.clear();
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}
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void	btUnionFind::reset(int N)
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{
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	allocate(N);
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	for (int i = 0; i < 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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class btUnionFindElementSortPredicate
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{
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	public:
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		bool operator() ( const btElement& lhs, const btElement& rhs ) const
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		{
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			return lhs.m_id < rhs.m_id;
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		}
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};
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///this is a special operation, destroying the content of btUnionFind.
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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	btUnionFind::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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#ifndef STATIC_SIMULATION_ISLAND_OPTIMIZATION
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		m_elements[i].m_sz = i;
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#endif //STATIC_SIMULATION_ISLAND_OPTIMIZATION
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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(), btUnionFindElementSortPredicate);
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	  m_elements.quickSort(btUnionFindElementSortPredicate());
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}
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