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Tidying up ImprovedCubicSurfaceExtractor.

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This commit is contained in:
David Williams 2011-05-14 12:30:39 +01:00
parent 5cca022fbe
commit 1a7647027d
2 changed files with 24 additions and 26 deletions
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37
library/PolyVoxCore/include/ImprovedCubicSurfaceExtractor.h
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@ -32,11 +32,6 @@ freely, subject to the following restrictions:
namespace PolyVox
{
struct Quad
{
uint32_t vertices[4];
};
template< template<typename> class VolumeType, typename VoxelType>
class ImprovedCubicSurfaceExtractor
{
@ -57,17 +52,23 @@ namespace PolyVox
NoOfFaces
};
struct Quad
{
uint32_t vertices[4];
};
public:
ImprovedCubicSurfaceExtractor(VolumeType<VoxelType>* volData, Region region, SurfaceMesh<PositionMaterial>* result, bool bMergeQuads = true);
void execute();
int32_t addVertex(float fX, float fY, float fZ, uint8_t uMaterial, Array<3, IndexAndMaterial>& existingVertices);
void execute();
private:
int32_t addVertex(float fX, float fY, float fZ, uint8_t uMaterial, Array<3, IndexAndMaterial>& existingVertices);
bool performQuadMerging(std::list<Quad>& quads);
bool mergeQuads(Quad& q1, Quad& q2);
//The volume data and a sampler to access it.
VolumeType<VoxelType>* m_volData;
typename VolumeType<VoxelType>::Sampler m_sampVolume;
//Information about the region we are currently processing
Region m_regSizeInVoxels;
@ -75,28 +76,22 @@ namespace PolyVox
//The surface patch we are currently filling.
SurfaceMesh<PositionMaterial>* m_meshCurrent;
//Array<4, IndexAndMaterial> m_vertices;
//Used to avoid creating duplicate vertices.
Array<3, IndexAndMaterial> m_previousSliceVertices;
Array<3, IndexAndMaterial> m_currentSliceVertices;
Array<4, uint8_t> m_faces;
//During extraction we create a number of different lists of quads. All the
//quads in a given list are in the same plane and facing in the same direction.
std::vector< std::list<Quad> > m_vecQuads[NoOfFaces];
//Controls whether quad merging should be performed. This might be undesirable
//is the user needs per-vertex attributes, or to perform per vertex lighting.
bool m_bMergeQuads;
//Although we try to avoid creating multiple vertices at the same location, sometimes this is unavoidable
//if they have different materials. For example, four different materials next to each other would mean
//four quads (though more triangles) sharing the vertex. As far as I can tell, four is the worst case scenario.
static const uint32_t MaxQuadsSharingVertex;
////////////////////////////////////////////////////////////////////////////////
// Decimation
////////////////////////////////////////////////////////////////////////////////
bool decimate(std::list<Quad>& quads);
bool mergeQuads(Quad& q1, Quad& q2);
static const uint32_t MaxQuadsSharingVertex;
};
}

13
library/PolyVoxCore/include/ImprovedCubicSurfaceExtractor.inl
View File

@ -35,7 +35,6 @@ namespace PolyVox
template< template<typename> class VolumeType, typename VoxelType>
ImprovedCubicSurfaceExtractor<VolumeType, VoxelType>::ImprovedCubicSurfaceExtractor(VolumeType<VoxelType>* volData, Region region, SurfaceMesh<PositionMaterial>* result, bool bMergeQuads)
:m_volData(volData)
,m_sampVolume(volData)
,m_regSizeInVoxels(region)
,m_meshCurrent(result)
,m_bMergeQuads(bMergeQuads)
@ -58,8 +57,6 @@ namespace PolyVox
uint32_t uRegionWidth = m_regSizeInVoxels.getUpperCorner().getX() - m_regSizeInVoxels.getLowerCorner().getX() + 1;
uint32_t uRegionHeight = m_regSizeInVoxels.getUpperCorner().getY() - m_regSizeInVoxels.getLowerCorner().getY() + 1;
uint32_t uRegionDepth = m_regSizeInVoxels.getUpperCorner().getZ() - m_regSizeInVoxels.getLowerCorner().getZ() + 1;
m_faces.resize(ArraySizes(uRegionWidth)(uRegionHeight)(uRegionDepth)(NoOfFaces));
memset(m_faces.getRawData(), 0x00, m_faces.getNoOfElements() * sizeof(uint8_t)); //Note: hard-coded type uint8_t
m_vecQuads[NegativeX].resize(m_regSizeInVoxels.getUpperCorner().getX() - m_regSizeInVoxels.getLowerCorner().getX() + 2);
m_vecQuads[PositiveX].resize(m_regSizeInVoxels.getUpperCorner().getX() - m_regSizeInVoxels.getLowerCorner().getX() + 2);
@ -218,7 +215,9 @@ namespace PolyVox
if(m_bMergeQuads)
{
while(decimate(listQuads)){}
//Repeatedly call this function until it returns
//false to indicate nothing more can be done.
while(performQuadMerging(listQuads)){}
}
std::list<Quad>::iterator iterEnd = listQuads.end();
@ -274,7 +273,7 @@ namespace PolyVox
}
template< template<typename> class VolumeType, typename VoxelType>
bool ImprovedCubicSurfaceExtractor<VolumeType, VoxelType>::decimate(std::list<Quad>& quads)
bool ImprovedCubicSurfaceExtractor<VolumeType, VoxelType>::performQuadMerging(std::list<Quad>& quads)
{
bool bDidMerge = false;
for(std::list<Quad>::iterator outerIter = quads.begin(); outerIter != quads.end(); outerIter++)
@ -310,6 +309,9 @@ namespace PolyVox
//so just check that the first pair or vertices match.
if(fabs(m_meshCurrent->getVertices()[q1.vertices[0]].getMaterial() - m_meshCurrent->getVertices()[q2.vertices[0]].getMaterial()) < 0.001)
{
//Now check whether quad 2 is adjacent to quad one by comparing vertices.
//Adjacent quads must share two vertices, and the second quad could be to the
//top, bottom, left, of right of the first one. This gives four combinations to test.
if((q1.vertices[0] == q2.vertices[1]) && ((q1.vertices[3] == q2.vertices[2])))
{
q1.vertices[0] = q2.vertices[0];
@ -336,6 +338,7 @@ namespace PolyVox
}
}
//Quads cannot be merged.
return false;
}
}