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XCEngine/engine/third_party/physx/source/physxextensions/src/tet/ExtTetUnionFind.cpp

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// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of NVIDIA CORPORATION nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright (c) 2008-2025 NVIDIA Corporation. All rights reserved.
#include "ExtTetUnionFind.h"
using namespace physx;
using namespace Ext;
//------------------------------------------------------------------------------------
void UnionFind::init(PxI32 numSets)
{
mEntries.resize(numSets);
for (PxI32 i = 0; i < numSets; i++) {
Entry &e = mEntries[i];
e.parent = i;
e.rank = 0;
e.setNr = i;
}
}
//------------------------------------------------------------------------------------
PxI32 UnionFind::find(PxI32 x)
{
if (mEntries[x].parent != x)
mEntries[x].parent = find(mEntries[x].parent);
return mEntries[x].parent;
}
//------------------------------------------------------------------------------------
void UnionFind::makeSet(PxI32 x, PxI32 y)
{
PxI32 xroot = find(x);
PxI32 yroot = find(y);
if (xroot == yroot)
return;
if (mEntries[xroot].rank < mEntries[yroot].rank)
mEntries[xroot].parent = yroot;
else if (mEntries[xroot].rank > mEntries[yroot].rank)
mEntries[yroot].parent = xroot;
else {
mEntries[yroot].parent = xroot;
mEntries[xroot].rank++;
}
}
//------------------------------------------------------------------------------------
PxI32 UnionFind::computeSetNrs()
{
PxArray<PxI32> oldToNew(mEntries.size(), -1);
PxI32 numSets = 0;
for (PxU32 i = 0; i < mEntries.size(); i++) {
PxI32 nr = find(i);
if (oldToNew[nr] < 0)
oldToNew[nr] = numSets++;
mEntries[i].setNr = oldToNew[nr];
}
return numSets;
}
//------------------------------------------------------------------------------------
PxI32 UnionFind::getSetNr(PxI32 x)
{
return mEntries[x].setNr;
}