158 lines
7.6 KiB
C++
158 lines
7.6 KiB
C++
#include "MeshDecimator.h"
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#include "SurfaceMesh.h"
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namespace PolyVox
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{
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template<>
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POLYVOX_API void MeshDecimator<PositionMaterial>::fillInitialVertexMetadata(std::vector<InitialVertexMetadata>& vecVertexMetadata)
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{
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vecVertexMetadata.clear();
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vecVertexMetadata.resize(m_pOutputMesh->m_vecVertices.size());
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//Initialise the metadata
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for(int ct = 0; ct < vecVertexMetadata.size(); ct++)
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{
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vecVertexMetadata[ct].normal.setElements(0,0,0);
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vecVertexMetadata[ct].isOnMaterialEdge = false;
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vecVertexMetadata[ct].isOnRegionFace.reset();
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}
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//Identify duplicate vertices, as they lie on the material edge. To do this we convert into integers and sort
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//(first on z, then y, then x). They should be mostly in order as this is the order they come out of the
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//CubicSurfaceExtractor in. Duplicates are now neighbours in the resulting list so just scan through for pairs.
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std::vector<IntVertex> intVertices;
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intVertices.reserve(m_pOutputMesh->m_vecVertices.size());
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for(int ct = 0; ct < m_pOutputMesh->m_vecVertices.size(); ct++)
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{
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const Vector3DFloat& floatPos = m_pOutputMesh->m_vecVertices[ct].position;
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IntVertex intVertex(static_cast<uint32_t>(floatPos.getX()), static_cast<uint32_t>(floatPos.getY()), static_cast<uint32_t>(floatPos.getZ()), ct);
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intVertices.push_back(intVertex);
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}
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//Do the sorting so that duplicate become neighbours
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sort(intVertices.begin(), intVertices.end());
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//Find neighbours which are duplicates.
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for(int ct = 0; ct < intVertices.size() - 1; ct++)
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{
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const IntVertex& v0 = intVertices[ct+0];
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const IntVertex& v1 = intVertices[ct+1];
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if((v0.x == v1.x) && (v0.y == v1.y) && (v0.z == v1.z))
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{
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vecVertexMetadata[v0.index].isOnMaterialEdge = true;
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vecVertexMetadata[v1.index].isOnMaterialEdge = true;
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}
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}
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//Compute an approcimation to the normal, used when deciding if an edge can collapse.
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for(int ct = 0; ct < m_pOutputMesh->m_vecVertices.size(); ct++)
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{
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Vector3DFloat sumOfNormals(0.0f,0.0f,0.0f);
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for(vector<uint32_t>::const_iterator iter = trianglesUsingVertex[ct].cbegin(); iter != trianglesUsingVertex[ct].cend(); iter++)
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{
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sumOfNormals += m_vecTriangles[*iter].normal;
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}
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vecVertexMetadata[ct].normal = sumOfNormals;
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vecVertexMetadata[ct].normal.normalise();
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}
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//Identify those vertices on the edge of a region. Care will need to be taken when moving them.
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for(int ct = 0; ct < vecVertexMetadata.size(); ct++)
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{
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Region regTransformed = m_pOutputMesh->m_Region;
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regTransformed.shift(regTransformed.getLowerCorner() * static_cast<int32_t>(-1));
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//Plus and minus X
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_X, m_pOutputMesh->m_vecVertices[ct].getPosition().getX() < regTransformed.getLowerCorner().getX() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_X, m_pOutputMesh->m_vecVertices[ct].getPosition().getX() > regTransformed.getUpperCorner().getX() - 0.001f);
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//Plus and minus Y
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_Y, m_pOutputMesh->m_vecVertices[ct].getPosition().getY() < regTransformed.getLowerCorner().getY() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_Y, m_pOutputMesh->m_vecVertices[ct].getPosition().getY() > regTransformed.getUpperCorner().getY() - 0.001f);
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//Plus and minus Z
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_Z, m_pOutputMesh->m_vecVertices[ct].getPosition().getZ() < regTransformed.getLowerCorner().getZ() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_Z, m_pOutputMesh->m_vecVertices[ct].getPosition().getZ() > regTransformed.getUpperCorner().getZ() - 0.001f);
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}
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}
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template<>
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POLYVOX_API void MeshDecimator<PositionMaterialNormal>::fillInitialVertexMetadata(std::vector<InitialVertexMetadata>& vecVertexMetadata)
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{
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vecVertexMetadata.clear();
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vecVertexMetadata.resize(m_pOutputMesh->m_vecVertices.size());
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//Initialise the metadata
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for(int ct = 0; ct < vecVertexMetadata.size(); ct++)
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{
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vecVertexMetadata[ct].isOnRegionFace.reset();
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vecVertexMetadata[ct].isOnMaterialEdge = false;
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vecVertexMetadata[ct].normal = m_pOutputMesh->m_vecVertices[ct].normal;
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}
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//Identify those vertices on the edge of a region. Care will need to be taken when moving them.
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for(int ct = 0; ct < vecVertexMetadata.size(); ct++)
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{
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Region regTransformed = m_pOutputMesh->m_Region;
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regTransformed.shift(regTransformed.getLowerCorner() * static_cast<int32_t>(-1));
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//Plus and minus X
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_X, m_pOutputMesh->m_vecVertices[ct].getPosition().getX() < regTransformed.getLowerCorner().getX() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_X, m_pOutputMesh->m_vecVertices[ct].getPosition().getX() > regTransformed.getUpperCorner().getX() - 0.001f);
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//Plus and minus Y
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_Y, m_pOutputMesh->m_vecVertices[ct].getPosition().getY() < regTransformed.getLowerCorner().getY() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_Y, m_pOutputMesh->m_vecVertices[ct].getPosition().getY() > regTransformed.getUpperCorner().getY() - 0.001f);
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//Plus and minus Z
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_NEG_Z, m_pOutputMesh->m_vecVertices[ct].getPosition().getZ() < regTransformed.getLowerCorner().getZ() + 0.001f);
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vecVertexMetadata[ct].isOnRegionFace.set(RFF_ON_REGION_FACE_POS_Z, m_pOutputMesh->m_vecVertices[ct].getPosition().getZ() > regTransformed.getUpperCorner().getZ() - 0.001f);
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}
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//If all three vertices have the same material then we are not on a material edge. If any vertex has a different
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//material then all three vertices are on a material edge. E.g. If one vertex has material 'a' and the other two
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//have material 'b', then the two 'b's are still on an edge (with 'a') even though they are the same as eachother.
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for(int ct = 0; ct < m_vecTriangles.size(); ct++)
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{
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uint32_t v0 = m_vecTriangles[ct].v0;
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uint32_t v1 = m_vecTriangles[ct].v1;
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uint32_t v2 = m_vecTriangles[ct].v2;
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bool allMatch =
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(m_pOutputMesh->m_vecVertices[v0].material == m_pOutputMesh->m_vecVertices[v1].material) &&
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(m_pOutputMesh->m_vecVertices[v1].material == m_pOutputMesh->m_vecVertices[v2].material);
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if(!allMatch)
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{
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vecVertexMetadata[v0].isOnMaterialEdge = true;
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vecVertexMetadata[v1].isOnMaterialEdge = true;
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vecVertexMetadata[v2].isOnMaterialEdge = true;
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}
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}
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}
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template<>
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POLYVOX_API bool MeshDecimator<PositionMaterialNormal>::canCollapseNormalEdge(uint32_t uSrc, uint32_t uDst)
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{
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if(m_vecInitialVertexMetadata[uSrc].normal.dot(m_vecInitialVertexMetadata[uDst].normal) < m_fMinDotProductForCollapse)
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{
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return false;
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}
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//With the marching cubes surface we honour the user specified threshold
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return !collapseChangesFaceNormals(uSrc, uDst, m_fMinDotProductForCollapse);
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}
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template<>
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POLYVOX_API bool MeshDecimator<PositionMaterial>::canCollapseNormalEdge(uint32_t uSrc, uint32_t uDst)
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{
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//We don't actually use the normal here, because we want to allow face
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//vertices to collapse onto edge vertices. Simply checking whether anything
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//has flipped has proved to be the most robust approach, though rather slow.
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//It's not sufficient to just check the normals, there can be holes in the middle
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//of the mesh for example.
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//User specified threshold is not used for cubic surface, any
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//movement is too much (but allow for floating point error).
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return !collapseChangesFaceNormals(uSrc, uDst, 0.999f);
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}
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}
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