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Refactoring CubicSurfaceExtractor to free functions rather than just wrapping a class.

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This commit is contained in:
David Williams 2015-12-08 23:50:41 +00:00
parent 9617197893
commit 43bb832c46
2 changed files with 91 additions and 94 deletions
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89
include/PolyVox/CubicSurfaceExtractor.h
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@ -86,6 +86,35 @@ namespace PolyVox
uint32_t vertices[4]; uint32_t vertices[4];
}; };
// This constant defines the maximum number of quads which can share a vertex in a cubic style mesh.
//
// We try to avoid duplicate vertices by checking whether a vertex has already been added at a given position.
// However, it is possible that vertices have the same position but different materials. In this case, the
// vertices are not true duplicates and both must be added to the mesh. As far as I can tell, it is possible to have
// at most eight vertices with the same position but different materials. For example, this worst-case scenario
// happens when we have a 2x2x2 group of voxels, all with different materials and some/all partially transparent.
// The vertex position at the center of this group is then going to be used by all eight voxels all with different
// materials.
const uint32_t MaxVerticesPerPosition = 8;
template<typename VolumeType>
struct IndexAndMaterial
{
int32_t iIndex;
typename VolumeType::VoxelType uMaterial;
};
enum FaceNames
{
PositiveX,
PositiveY,
PositiveZ,
NegativeX,
NegativeY,
NegativeZ,
NoOfFaces
};
template<typename MeshType> template<typename MeshType>
bool mergeQuads(Quad& q1, Quad& q2, MeshType* m_meshCurrent) bool mergeQuads(Quad& q1, Quad& q2, MeshType* m_meshCurrent)
{ {
@ -155,27 +184,43 @@ namespace PolyVox
return bDidMerge; return bDidMerge;
} }
template<typename VolumeType, typename MeshType>
int32_t addVertex(uint32_t uX, uint32_t uY, uint32_t uZ, typename VolumeType::VoxelType uMaterialIn, Array<3, IndexAndMaterial<VolumeType> >& existingVertices, MeshType* m_meshCurrent)
{
for (uint32_t ct = 0; ct < MaxVerticesPerPosition; ct++)
{
IndexAndMaterial<VolumeType>& rEntry = existingVertices(uX, uY, ct);
if (rEntry.iIndex == -1)
{
//No vertices matched and we've now hit an empty space. Fill it by creating a vertex. The 0.5f offset is because vertices set between voxels in order to build cubes around them.
CubicVertex<typename VolumeType::VoxelType> cubicVertex;
cubicVertex.encodedPosition.setElements(static_cast<uint8_t>(uX), static_cast<uint8_t>(uY), static_cast<uint8_t>(uZ));
cubicVertex.data = uMaterialIn;
rEntry.iIndex = m_meshCurrent->addVertex(cubicVertex);
rEntry.uMaterial = uMaterialIn;
return rEntry.iIndex;
}
//If we have an existing vertex and the material matches then we can return it.
if (rEntry.uMaterial == uMaterialIn)
{
return rEntry.iIndex;
}
}
// If we exit the loop here then apparently all the slots were full but none of them matched.
// This shouldn't ever happen, so if it does it is probably a bug in PolyVox. Please report it to us!
POLYVOX_THROW(std::runtime_error, "All slots full but no matches during cubic surface extraction. This is probably a bug in PolyVox");
return -1; //Should never happen.
}
/// Do not use this class directly. Use the 'extractCubicSurface' function instead (see examples). /// Do not use this class directly. Use the 'extractCubicSurface' function instead (see examples).
template<typename VolumeType, typename MeshType, typename IsQuadNeeded> template<typename VolumeType, typename MeshType, typename IsQuadNeeded>
class CubicSurfaceExtractor class CubicSurfaceExtractor
{ {
struct IndexAndMaterial
{
int32_t iIndex;
typename VolumeType::VoxelType uMaterial;
};
enum FaceNames
{
PositiveX,
PositiveY,
PositiveZ,
NegativeX,
NegativeY,
NegativeZ,
NoOfFaces
};
public: public:
CubicSurfaceExtractor(VolumeType* volData, Region region, MeshType* result, IsQuadNeeded isQuadNeeded = IsQuadNeeded(), bool bMergeQuads = true); CubicSurfaceExtractor(VolumeType* volData, Region region, MeshType* result, IsQuadNeeded isQuadNeeded = IsQuadNeeded(), bool bMergeQuads = true);
@ -183,8 +228,6 @@ namespace PolyVox
void execute(); void execute();
private: private:
int32_t addVertex(uint32_t uX, uint32_t uY, uint32_t uZ, typename VolumeType::VoxelType uMaterial, Array<3, IndexAndMaterial>& existingVertices);
IsQuadNeeded m_funcIsQuadNeededCallback; IsQuadNeeded m_funcIsQuadNeededCallback;
//The volume data and a sampler to access it. //The volume data and a sampler to access it.
@ -197,8 +240,8 @@ namespace PolyVox
MeshType* m_meshCurrent; MeshType* m_meshCurrent;
//Used to avoid creating duplicate vertices. //Used to avoid creating duplicate vertices.
Array<3, IndexAndMaterial> m_previousSliceVertices; Array<3, IndexAndMaterial<VolumeType> > m_previousSliceVertices;
Array<3, IndexAndMaterial> m_currentSliceVertices; Array<3, IndexAndMaterial<VolumeType> > m_currentSliceVertices;
//During extraction we create a number of different lists of quads. All the //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. //quads in a given list are in the same plane and facing in the same direction.
@ -207,10 +250,6 @@ namespace PolyVox
//Controls whether quad merging should be performed. This might be undesirable //Controls whether quad merging should be performed. This might be undesirable
//is the user needs per-vertex attributes, or to perform per vertex lighting. //is the user needs per-vertex attributes, or to perform per vertex lighting.
bool m_bMergeQuads; bool m_bMergeQuads;
//This constant defines the maximum number of quads which can share a
//vertex in a cubic style mesh. See the initialisation for more details.
static const uint32_t MaxVerticesPerPosition;
}; };
// This version of the function performs the extraction into a user-provided mesh rather than allocating a mesh automatically. // This version of the function performs the extraction into a user-provided mesh rather than allocating a mesh automatically.

96
include/PolyVox/CubicSurfaceExtractor.inl
View File

@ -25,16 +25,6 @@ freely, subject to the following restrictions:
namespace PolyVox namespace PolyVox
{ {
// We try to avoid duplicate vertices by checking whether a vertex has already been added at a given position.
// However, it is possible that vertices have the same position but different materials. In this case, the
// vertices are not true duplicates and both must be added to the mesh. As far as I can tell, it is possible to have
// at most eight vertices with the same position but different materials. For example, this worst-case scenario
// happens when we have a 2x2x2 group of voxels, all with different materials and some/all partially transparent.
// The vertex position at the center of this group is then going to be used by all eight voxels all with different
// materials.
template<typename VolumeType, typename MeshType, typename IsQuadNeeded>
const uint32_t CubicSurfaceExtractor<VolumeType, MeshType, IsQuadNeeded>::MaxVerticesPerPosition = 8;
template<typename VolumeType, typename MeshType, typename IsQuadNeeded> template<typename VolumeType, typename MeshType, typename IsQuadNeeded>
CubicSurfaceExtractor<VolumeType, MeshType, IsQuadNeeded>::CubicSurfaceExtractor(VolumeType* volData, Region region, MeshType* result, IsQuadNeeded isQuadNeeded, bool bMergeQuads) CubicSurfaceExtractor<VolumeType, MeshType, IsQuadNeeded>::CubicSurfaceExtractor(VolumeType* volData, Region region, MeshType* result, IsQuadNeeded isQuadNeeded, bool bMergeQuads)
:m_volData(volData) :m_volData(volData)
@ -65,8 +55,8 @@ namespace PolyVox
//uint32_t arraySize[3]= {uArrayWidth, uArrayHeight, MaxVerticesPerPosition}; //uint32_t arraySize[3]= {uArrayWidth, uArrayHeight, MaxVerticesPerPosition};
//m_previousSliceVertices.resize(arraySize); //m_previousSliceVertices.resize(arraySize);
//m_currentSliceVertices.resize(arraySize); //m_currentSliceVertices.resize(arraySize);
memset(m_previousSliceVertices.getRawData(), 0xff, m_previousSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial)); memset(m_previousSliceVertices.getRawData(), 0xff, m_previousSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial<VolumeType>));
memset(m_currentSliceVertices.getRawData(), 0xff, m_currentSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial)); memset(m_currentSliceVertices.getRawData(), 0xff, m_currentSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial<VolumeType>));
m_vecQuads[NegativeX].resize(m_regSizeInVoxels.getUpperX() - m_regSizeInVoxels.getLowerX() + 2); m_vecQuads[NegativeX].resize(m_regSizeInVoxels.getUpperX() - m_regSizeInVoxels.getLowerX() + 2);
m_vecQuads[PositiveX].resize(m_regSizeInVoxels.getUpperX() - m_regSizeInVoxels.getLowerX() + 2); m_vecQuads[PositiveX].resize(m_regSizeInVoxels.getUpperX() - m_regSizeInVoxels.getLowerX() + 2);
@ -102,20 +92,20 @@ namespace PolyVox
// X // X
if(m_funcIsQuadNeededCallback(currentVoxel, negXVoxel, material)) if(m_funcIsQuadNeededCallback(currentVoxel, negXVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices); uint32_t v1 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX , regY + 1, regZ + 1, material, m_currentSliceVertices); uint32_t v2 = addVertex(regX , regY + 1, regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices); uint32_t v3 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
m_vecQuads[NegativeX][regX].push_back(Quad(v0, v1, v2, v3)); m_vecQuads[NegativeX][regX].push_back(Quad(v0, v1, v2, v3));
} }
if(m_funcIsQuadNeededCallback(negXVoxel, currentVoxel, material)) if(m_funcIsQuadNeededCallback(negXVoxel, currentVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices); uint32_t v1 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX , regY + 1, regZ + 1, material, m_currentSliceVertices); uint32_t v2 = addVertex(regX , regY + 1, regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices); uint32_t v3 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
m_vecQuads[PositiveX][regX].push_back(Quad(v0, v3, v2, v1)); m_vecQuads[PositiveX][regX].push_back(Quad(v0, v3, v2, v1));
} }
@ -123,20 +113,20 @@ namespace PolyVox
// Y // Y
if(m_funcIsQuadNeededCallback(currentVoxel, negYVoxel, material)) if(m_funcIsQuadNeededCallback(currentVoxel, negYVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices); uint32_t v1 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX + 1, regY , regZ + 1, material, m_currentSliceVertices); uint32_t v2 = addVertex(regX + 1, regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices); uint32_t v3 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
m_vecQuads[NegativeY][regY].push_back(Quad(v0, v1, v2, v3)); m_vecQuads[NegativeY][regY].push_back(Quad(v0, v1, v2, v3));
} }
if(m_funcIsQuadNeededCallback(negYVoxel, currentVoxel, material)) if(m_funcIsQuadNeededCallback(negYVoxel, currentVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices); uint32_t v1 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX + 1, regY , regZ + 1, material, m_currentSliceVertices); uint32_t v2 = addVertex(regX + 1, regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices); uint32_t v3 = addVertex(regX , regY , regZ + 1, material, m_currentSliceVertices, m_meshCurrent);
m_vecQuads[PositiveY][regY].push_back(Quad(v0, v3, v2, v1)); m_vecQuads[PositiveY][regY].push_back(Quad(v0, v3, v2, v1));
} }
@ -144,20 +134,20 @@ namespace PolyVox
// Z // Z
if(m_funcIsQuadNeededCallback(currentVoxel, negZVoxel, material)) if(m_funcIsQuadNeededCallback(currentVoxel, negZVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices); uint32_t v1 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX + 1, regY + 1, regZ , material, m_previousSliceVertices); uint32_t v2 = addVertex(regX + 1, regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices); uint32_t v3 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
m_vecQuads[NegativeZ][regZ].push_back(Quad(v0, v1, v2, v3)); m_vecQuads[NegativeZ][regZ].push_back(Quad(v0, v1, v2, v3));
} }
if(m_funcIsQuadNeededCallback(negZVoxel, currentVoxel, material)) if(m_funcIsQuadNeededCallback(negZVoxel, currentVoxel, material))
{ {
uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices); uint32_t v0 = addVertex(regX , regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v1 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices); uint32_t v1 = addVertex(regX , regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v2 = addVertex(regX + 1, regY + 1, regZ , material, m_previousSliceVertices); uint32_t v2 = addVertex(regX + 1, regY + 1, regZ , material, m_previousSliceVertices, m_meshCurrent);
uint32_t v3 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices); uint32_t v3 = addVertex(regX + 1, regY , regZ , material, m_previousSliceVertices, m_meshCurrent);
m_vecQuads[PositiveZ][regZ].push_back(Quad(v0, v3, v2, v1)); m_vecQuads[PositiveZ][regZ].push_back(Quad(v0, v3, v2, v1));
} }
@ -167,7 +157,7 @@ namespace PolyVox
} }
m_previousSliceVertices.swap(m_currentSliceVertices); m_previousSliceVertices.swap(m_currentSliceVertices);
memset(m_currentSliceVertices.getRawData(), 0xff, m_currentSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial)); memset(m_currentSliceVertices.getRawData(), 0xff, m_currentSliceVertices.getNoOfElements() * sizeof(IndexAndMaterial<VolumeType>));
} }
for(uint32_t uFace = 0; uFace < NoOfFaces; uFace++) for(uint32_t uFace = 0; uFace < NoOfFaces; uFace++)
@ -202,36 +192,4 @@ namespace PolyVox
"ms (Region size = ", m_regSizeInVoxels.getWidthInVoxels(), "x", m_regSizeInVoxels.getHeightInVoxels(), "ms (Region size = ", m_regSizeInVoxels.getWidthInVoxels(), "x", m_regSizeInVoxels.getHeightInVoxels(),
"x", m_regSizeInVoxels.getDepthInVoxels(), ")"); "x", m_regSizeInVoxels.getDepthInVoxels(), ")");
} }
template<typename VolumeType, typename MeshType, typename IsQuadNeeded>
int32_t CubicSurfaceExtractor<VolumeType, MeshType, IsQuadNeeded>::addVertex(uint32_t uX, uint32_t uY, uint32_t uZ, typename VolumeType::VoxelType uMaterialIn, Array<3, IndexAndMaterial>& existingVertices)
{
for(uint32_t ct = 0; ct < MaxVerticesPerPosition; ct++)
{
IndexAndMaterial& rEntry = existingVertices(uX, uY, ct);
if(rEntry.iIndex == -1)
{
//No vertices matched and we've now hit an empty space. Fill it by creating a vertex. The 0.5f offset is because vertices set between voxels in order to build cubes around them.
CubicVertex<typename VolumeType::VoxelType> cubicVertex;
cubicVertex.encodedPosition.setElements(static_cast<uint8_t>(uX), static_cast<uint8_t>(uY), static_cast<uint8_t>(uZ));
cubicVertex.data = uMaterialIn;
rEntry.iIndex = m_meshCurrent->addVertex(cubicVertex);
rEntry.uMaterial = uMaterialIn;
return rEntry.iIndex;
}
//If we have an existing vertex and the material matches then we can return it.
if(rEntry.uMaterial == uMaterialIn)
{
return rEntry.iIndex;
}
}
// If we exit the loop here then apparently all the slots were full but none of them matched.
// This shouldn't ever happen, so if it does it is probably a bug in PolyVox. Please report it to us!
POLYVOX_THROW(std::runtime_error, "All slots full but no matches during cubic surface extraction. This is probably a bug in PolyVox");
return -1; //Should never happen.
}
} }