68 lines
2 KiB
C++
68 lines
2 KiB
C++
// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
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// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
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// SPDX-License-Identifier: MIT
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#include <Jolt/Jolt.h>
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#include <Jolt/TriangleSplitter/TriangleSplitter.h>
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JPH_NAMESPACE_BEGIN
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TriangleSplitter::TriangleSplitter(const VertexList &inVertices, const IndexedTriangleList &inTriangles) :
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mVertices(inVertices),
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mTriangles(inTriangles)
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{
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mSortedTriangleIdx.resize(inTriangles.size());
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mCentroids.resize(inTriangles.size());
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for (uint t = 0; t < inTriangles.size(); ++t)
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{
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// Initially triangles start unsorted
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mSortedTriangleIdx[t] = t;
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// Calculate centroid
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inTriangles[t].GetCentroid(inVertices).StoreFloat3(&mCentroids[t]);
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}
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}
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bool TriangleSplitter::SplitInternal(const Range &inTriangles, uint inDimension, float inSplit, Range &outLeft, Range &outRight)
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{
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// Divide triangles
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uint start = inTriangles.mBegin, end = inTriangles.mEnd;
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while (start < end)
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{
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// Search for first element that is on the right hand side of the split plane
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while (start < end && mCentroids[mSortedTriangleIdx[start]][inDimension] < inSplit)
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++start;
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// Search for the first element that is on the left hand side of the split plane
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while (start < end && mCentroids[mSortedTriangleIdx[end - 1]][inDimension] >= inSplit)
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--end;
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if (start < end)
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{
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// Swap the two elements
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std::swap(mSortedTriangleIdx[start], mSortedTriangleIdx[end - 1]);
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++start;
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--end;
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}
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}
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JPH_ASSERT(start == end);
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#ifdef JPH_ENABLE_ASSERTS
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// Validate division algorithm
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JPH_ASSERT(inTriangles.mBegin <= start);
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JPH_ASSERT(start <= inTriangles.mEnd);
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for (uint i = inTriangles.mBegin; i < start; ++i)
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JPH_ASSERT(mCentroids[mSortedTriangleIdx[i]][inDimension] < inSplit);
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for (uint i = start; i < inTriangles.mEnd; ++i)
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JPH_ASSERT(mCentroids[mSortedTriangleIdx[i]][inDimension] >= inSplit);
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#endif
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outLeft = Range(inTriangles.mBegin, start);
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outRight = Range(start, inTriangles.mEnd);
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return outLeft.Count() > 0 && outRight.Count() > 0;
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}
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JPH_NAMESPACE_END
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