92 lines
2.7 KiB
C++
92 lines
2.7 KiB
C++
// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
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#if COMPILE_WITH_MODEL_TOOL && USE_EDITOR
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#include "VertexTriangleAdjacency.h"
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#include "Engine/Core/Math/Math.h"
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VertexTriangleAdjacency::VertexTriangleAdjacency(uint32* indices, int32 indicesCount, uint32 vertexCount, bool computeNumTriangles)
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{
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// Compute the number of referenced vertices if it wasn't specified by the caller
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const uint32* const indicesEnd = indices + indicesCount;
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if (vertexCount == 0)
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{
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for (uint32* triangle = indices; triangle != indicesEnd; triangle += 3)
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{
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ASSERT(nullptr != triangle);
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vertexCount = Math::Max(vertexCount, triangle[0]);
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vertexCount = Math::Max(vertexCount, triangle[1]);
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vertexCount = Math::Max(vertexCount, triangle[2]);
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}
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}
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NumVertices = vertexCount;
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uint32* pi;
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// Allocate storage
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if (computeNumTriangles)
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{
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pi = LiveTriangles = new uint32[vertexCount + 1];
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Platform::MemoryClear(LiveTriangles, sizeof(uint32) * (vertexCount + 1));
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OffsetTable = new uint32[vertexCount + 2] + 1;
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}
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else
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{
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pi = OffsetTable = new uint32[vertexCount + 2] + 1;
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Platform::MemoryClear(OffsetTable, sizeof(uint32) * (vertexCount + 1));
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LiveTriangles = nullptr; // Important, otherwise the d'tor would crash
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}
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// Get a pointer to the end of the buffer
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uint32* piEnd = pi + vertexCount;
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*piEnd++ = 0u;
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// First pass: compute the number of faces referencing each vertex
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for (uint32* triangle = indices; triangle != indicesEnd; triangle += 3)
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{
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pi[triangle[0]]++;
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pi[triangle[1]]++;
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pi[triangle[2]]++;
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}
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// Second pass: compute the final offset table
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int32 iSum = 0;
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uint32* piCurOut = OffsetTable;
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for (uint32* piCur = pi; piCur != piEnd; ++piCur, piCurOut++)
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{
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const int32 iLastSum = iSum;
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iSum += *piCur;
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*piCurOut = iLastSum;
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}
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pi = this->OffsetTable;
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// Third pass: compute the final table
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AdjacencyTable = new uint32[iSum];
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iSum = 0;
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for (uint32* triangle = indices; triangle != indicesEnd; triangle += 3, iSum++)
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{
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uint32 idx = triangle[0];
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AdjacencyTable[pi[idx]++] = iSum;
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idx = triangle[1];
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AdjacencyTable[pi[idx]++] = iSum;
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idx = triangle[2];
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AdjacencyTable[pi[idx]++] = iSum;
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}
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// Fourth pass: undo the offset computations made during the third pass
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// We could do this in a separate buffer, but this would be TIMES slower.
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OffsetTable--;
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*OffsetTable = 0u;
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}
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VertexTriangleAdjacency::~VertexTriangleAdjacency()
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{
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delete[] OffsetTable;
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delete[] AdjacencyTable;
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delete[] LiveTriangles;
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}
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#endif
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