326 lines
14 KiB
C++
326 lines
14 KiB
C++
/*******************************************************************************
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Copyright (c) 2005-2009 David Williams
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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*******************************************************************************/
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#include "PolyVox/Impl/Timer.h"
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namespace PolyVox
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{
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template<typename VolumeType, typename MeshType, typename ControllerType>
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MarchingCubesSurfaceExtractor<VolumeType, MeshType, ControllerType>::MarchingCubesSurfaceExtractor(VolumeType* volData, Region region, MeshType* result, ControllerType controller)
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:m_volData(volData)
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,m_meshCurrent(result)
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,m_regSizeInVoxels(region)
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,m_controller(controller)
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,m_tThreshold(m_controller.getThreshold())
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{
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POLYVOX_THROW_IF(m_meshCurrent == nullptr, std::invalid_argument, "Provided mesh cannot be null");
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}
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template<typename VolumeType, typename MeshType, typename ControllerType>
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void MarchingCubesSurfaceExtractor<VolumeType, MeshType, ControllerType>::execute()
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{
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Timer timer;
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m_meshCurrent->clear();
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computeBitmaskForSlice();
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m_meshCurrent->setOffset(m_regSizeInVoxels.getLowerCorner());
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POLYVOX_LOG_TRACE("Marching cubes surface extraction took ", timer.elapsedTimeInMilliSeconds(),
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"ms (Region size = ", m_regSizeInVoxels.getWidthInVoxels(), "x", m_regSizeInVoxels.getHeightInVoxels(),
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"x", m_regSizeInVoxels.getDepthInVoxels(), ")");
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}
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template<typename VolumeType, typename MeshType, typename ControllerType>
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void MarchingCubesSurfaceExtractor<VolumeType, MeshType, ControllerType>::computeBitmaskForSlice()
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{
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const uint32_t uArrayWidth = m_regSizeInVoxels.getUpperX() - m_regSizeInVoxels.getLowerX() + 2;
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const uint32_t uArrayHeight = m_regSizeInVoxels.getUpperY() - m_regSizeInVoxels.getLowerY() + 2;
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const uint32_t uArrayDepth = m_regSizeInVoxels.getUpperZ() - m_regSizeInVoxels.getLowerZ() + 2;
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//For edge indices
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Array3DInt32 pIndicesX(uArrayWidth, uArrayHeight, uArrayDepth);
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Array3DInt32 pIndicesY(uArrayWidth, uArrayHeight, uArrayDepth);
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Array3DInt32 pIndicesZ(uArrayWidth, uArrayHeight, uArrayDepth);
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memset(pIndicesX.getRawData(), 0xff, pIndicesX.getNoOfElements() * 4);
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memset(pIndicesY.getRawData(), 0xff, pIndicesY.getNoOfElements() * 4);
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memset(pIndicesZ.getRawData(), 0xff, pIndicesZ.getNoOfElements() * 4);
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Array2DUint8 pPreviousSliceBitmask(uArrayWidth, uArrayHeight);
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Array1DUint8 pPreviousRowBitmask(uArrayWidth);
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memset(pPreviousSliceBitmask.getRawData(), 0x00, pPreviousSliceBitmask.getNoOfElements());
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memset(pPreviousRowBitmask.getRawData(), 0x00, pPreviousRowBitmask.getNoOfElements());
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uint8_t uPreviousCell = 0;
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typename VolumeType::Sampler startOfSlice(m_volData);
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startOfSlice.setPosition(m_regSizeInVoxels.getLowerX(), m_regSizeInVoxels.getLowerY(), m_regSizeInVoxels.getLowerZ());
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for (int32_t iZVolSpace = m_regSizeInVoxels.getLowerZ(); iZVolSpace <= m_regSizeInVoxels.getUpperZ(); iZVolSpace++)
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{
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const uint32_t uZRegSpace = iZVolSpace - m_regSizeInVoxels.getLowerZ();
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typename VolumeType::Sampler startOfRow = startOfSlice;
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for (int32_t iYVolSpace = m_regSizeInVoxels.getLowerY(); iYVolSpace <= m_regSizeInVoxels.getUpperY(); iYVolSpace++)
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{
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const uint32_t uYRegSpace = iYVolSpace - m_regSizeInVoxels.getLowerY();
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// Copying a sampler which is already pointing at the correct location seems (slightly) faster than
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// calling setPosition(). Therefore we make use of 'startOfRow' and 'startOfSlice' to reset the sampler.
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typename VolumeType::Sampler sampler = startOfRow;
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for (int32_t iXVolSpace = m_regSizeInVoxels.getLowerX(); iXVolSpace <= m_regSizeInVoxels.getUpperX(); iXVolSpace++)
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{
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const uint32_t uXRegSpace = iXVolSpace - m_regSizeInVoxels.getLowerX();
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uint8_t iCubeIndex = 0;
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// Four bits of our cube index are obtained by looking at the cube index for
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// the previous slice and copying four of those bits into their new positions.
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uint8_t iPreviousCubeIndexZ = pPreviousSliceBitmask(uXRegSpace, uYRegSpace);
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iPreviousCubeIndexZ >>= 4;
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iCubeIndex |= iPreviousCubeIndexZ;
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// Two bits of our cube index are obtained by looking at the cube index for
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// the previous row and copying two of those bits into their new positions.
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uint8_t iPreviousCubeIndexY = pPreviousRowBitmask(uXRegSpace);
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iPreviousCubeIndexY &= 204; //204 = 128+64+8+4
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iPreviousCubeIndexY >>= 2;
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iCubeIndex |= iPreviousCubeIndexY;
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// One bit of our cube index are obtained by looking at the cube index for
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// the previous cell and copying one of those bits into it's new position.
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uint8_t iPreviousCubeIndexX = uPreviousCell;
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iPreviousCubeIndexX &= 170; //170 = 128+32+8+2
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iPreviousCubeIndexX >>= 1;
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iCubeIndex |= iPreviousCubeIndexX;
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// The last bit of our cube index is obtained by looking
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// at the relevant voxel and comparing it to the threshold
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typename VolumeType::VoxelType v111 = sampler.getVoxel();
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if (m_controller.convertToDensity(v111) < m_tThreshold) iCubeIndex |= 128;
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// The current value becomes the previous value, ready for the next iteration.
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uPreviousCell = iCubeIndex;
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pPreviousRowBitmask(uXRegSpace) = iCubeIndex;
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pPreviousSliceBitmask(uXRegSpace, uYRegSpace) = iCubeIndex;
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/* Cube is entirely in/out of the surface */
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if (edgeTable[iCubeIndex] != 0)
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{
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// These three might not have been sampled, as v111 is the only one we sample every iteration.
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typename VolumeType::VoxelType v110 = sampler.peekVoxel0px0py1nz();
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typename VolumeType::VoxelType v101 = sampler.peekVoxel0px1ny0pz();
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typename VolumeType::VoxelType v011 = sampler.peekVoxel1nx0py0pz();
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const Vector3DFloat n000 = computeCentralDifferenceGradient(sampler);
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/* Find the vertices where the surface intersects the cube */
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if ((edgeTable[iCubeIndex] & 64) && (uXRegSpace > 0))
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{
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sampler.moveNegativeX();
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POLYVOX_ASSERT(v011 != v111, "Attempting to insert vertex between two voxels with the same value");
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const Vector3DFloat n100 = computeCentralDifferenceGradient(sampler);
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const float fInterp = static_cast<float>(m_tThreshold - m_controller.convertToDensity(v011)) / static_cast<float>(m_controller.convertToDensity(v111) - m_controller.convertToDensity(v011));
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const Vector3DFloat v3dPosition(static_cast<float>(uXRegSpace - 1) + fInterp, static_cast<float>(uYRegSpace), static_cast<float>(uZRegSpace));
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const Vector3DUint16 v3dScaledPosition(static_cast<uint16_t>(v3dPosition.getX() * 256.0f), static_cast<uint16_t>(v3dPosition.getY() * 256.0f), static_cast<uint16_t>(v3dPosition.getZ() * 256.0f));
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Vector3DFloat v3dNormal = (n100*fInterp) + (n000*(1 - fInterp));
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// The gradient for a voxel can be zero (e.g. solid voxel surrounded by empty ones) and so
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// the interpolated normal can also be zero (e.g. a grid of alternating solid and empty voxels).
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if (v3dNormal.lengthSquared() > 0.000001f)
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{
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v3dNormal.normalise();
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}
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// Allow the controller to decide how the material should be derived from the voxels.
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const typename VolumeType::VoxelType uMaterial = m_controller.blendMaterials(v011, v111, fInterp);
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MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
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surfaceVertex.encodedPosition = v3dScaledPosition;
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surfaceVertex.encodedNormal = encodeNormal(v3dNormal);
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surfaceVertex.data = uMaterial;
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const uint32_t uLastVertexIndex = m_meshCurrent->addVertex(surfaceVertex);
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pIndicesX(uXRegSpace, uYRegSpace, uZRegSpace) = uLastVertexIndex;
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sampler.movePositiveX();
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}
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if ((edgeTable[iCubeIndex] & 32) && (uYRegSpace > 0))
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{
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sampler.moveNegativeY();
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POLYVOX_ASSERT(v101 != v111, "Attempting to insert vertex between two voxels with the same value");
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const Vector3DFloat n010 = computeCentralDifferenceGradient(sampler);
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const float fInterp = static_cast<float>(m_tThreshold - m_controller.convertToDensity(v101)) / static_cast<float>(m_controller.convertToDensity(v111) - m_controller.convertToDensity(v101));
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const Vector3DFloat v3dPosition(static_cast<float>(uXRegSpace), static_cast<float>(uYRegSpace - 1) + fInterp, static_cast<float>(uZRegSpace));
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const Vector3DUint16 v3dScaledPosition(static_cast<uint16_t>(v3dPosition.getX() * 256.0f), static_cast<uint16_t>(v3dPosition.getY() * 256.0f), static_cast<uint16_t>(v3dPosition.getZ() * 256.0f));
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Vector3DFloat v3dNormal = (n010*fInterp) + (n000*(1 - fInterp));
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// The gradient for a voxel can be zero (e.g. solid voxel surrounded by empty ones) and so
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// the interpolated normal can also be zero (e.g. a grid of alternating solid and empty voxels).
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if (v3dNormal.lengthSquared() > 0.000001f)
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{
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v3dNormal.normalise();
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}
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// Allow the controller to decide how the material should be derived from the voxels.
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const typename VolumeType::VoxelType uMaterial = m_controller.blendMaterials(v101, v111, fInterp);
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MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
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surfaceVertex.encodedPosition = v3dScaledPosition;
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surfaceVertex.encodedNormal = encodeNormal(v3dNormal);
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surfaceVertex.data = uMaterial;
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uint32_t uLastVertexIndex = m_meshCurrent->addVertex(surfaceVertex);
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pIndicesY(uXRegSpace, uYRegSpace, uZRegSpace) = uLastVertexIndex;
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sampler.movePositiveY();
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}
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if ((edgeTable[iCubeIndex] & 1024) && (uZRegSpace > 0))
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{
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sampler.moveNegativeZ();
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POLYVOX_ASSERT(v110 != v111, "Attempting to insert vertex between two voxels with the same value");
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const Vector3DFloat n001 = computeCentralDifferenceGradient(sampler);
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const float fInterp = static_cast<float>(m_tThreshold - m_controller.convertToDensity(v110)) / static_cast<float>(m_controller.convertToDensity(v111) - m_controller.convertToDensity(v110));
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const Vector3DFloat v3dPosition(static_cast<float>(uXRegSpace), static_cast<float>(uYRegSpace), static_cast<float>(uZRegSpace - 1) + fInterp);
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const Vector3DUint16 v3dScaledPosition(static_cast<uint16_t>(v3dPosition.getX() * 256.0f), static_cast<uint16_t>(v3dPosition.getY() * 256.0f), static_cast<uint16_t>(v3dPosition.getZ() * 256.0f));
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Vector3DFloat v3dNormal = (n001*fInterp) + (n000*(1 - fInterp));
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// The gradient for a voxel can be zero (e.g. solid voxel surrounded by empty ones) and so
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// the interpolated normal can also be zero (e.g. a grid of alternating solid and empty voxels).
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if (v3dNormal.lengthSquared() > 0.000001f)
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{
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v3dNormal.normalise();
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}
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// Allow the controller to decide how the material should be derived from the voxels.
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const typename VolumeType::VoxelType uMaterial = m_controller.blendMaterials(v110, v111, fInterp);
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MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
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surfaceVertex.encodedPosition = v3dScaledPosition;
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surfaceVertex.encodedNormal = encodeNormal(v3dNormal);
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surfaceVertex.data = uMaterial;
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const uint32_t uLastVertexIndex = m_meshCurrent->addVertex(surfaceVertex);
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pIndicesZ(uXRegSpace, uYRegSpace, uZRegSpace) = uLastVertexIndex;
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sampler.movePositiveZ();
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}
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// Now output the indices. For the first row, column or slice there aren't
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// any (the region size in cells is one less than the region size in voxels)
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if ((uXRegSpace != 0) && (uYRegSpace != 0) && (uZRegSpace != 0))
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{
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int32_t indlist[12];
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sampler.setPosition(iXVolSpace, iYVolSpace, iZVolSpace);
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/* Cube is entirely in/out of the surface */
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if (edgeTable[iCubeIndex] != 0)
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{
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/* Find the vertices where the surface intersects the cube */
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if (edgeTable[iCubeIndex] & 1)
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{
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indlist[0] = pIndicesX(uXRegSpace, uYRegSpace - 1, uZRegSpace - 1);
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}
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if (edgeTable[iCubeIndex] & 2)
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{
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indlist[1] = pIndicesY(uXRegSpace, uYRegSpace, uZRegSpace - 1);
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}
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if (edgeTable[iCubeIndex] & 4)
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{
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indlist[2] = pIndicesX(uXRegSpace, uYRegSpace, uZRegSpace - 1);
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}
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if (edgeTable[iCubeIndex] & 8)
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{
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indlist[3] = pIndicesY(uXRegSpace - 1, uYRegSpace, uZRegSpace - 1);
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}
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if (edgeTable[iCubeIndex] & 16)
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{
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indlist[4] = pIndicesX(uXRegSpace, uYRegSpace - 1, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 32)
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{
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indlist[5] = pIndicesY(uXRegSpace, uYRegSpace, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 64)
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{
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indlist[6] = pIndicesX(uXRegSpace, uYRegSpace, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 128)
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{
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indlist[7] = pIndicesY(uXRegSpace - 1, uYRegSpace, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 256)
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{
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indlist[8] = pIndicesZ(uXRegSpace - 1, uYRegSpace - 1, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 512)
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{
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indlist[9] = pIndicesZ(uXRegSpace, uYRegSpace - 1, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 1024)
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{
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indlist[10] = pIndicesZ(uXRegSpace, uYRegSpace, uZRegSpace);
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}
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if (edgeTable[iCubeIndex] & 2048)
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{
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indlist[11] = pIndicesZ(uXRegSpace - 1, uYRegSpace, uZRegSpace);
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}
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for (int i = 0; triTable[iCubeIndex][i] != -1; i += 3)
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{
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const int32_t ind0 = indlist[triTable[iCubeIndex][i]];
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const int32_t ind1 = indlist[triTable[iCubeIndex][i + 1]];
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const int32_t ind2 = indlist[triTable[iCubeIndex][i + 2]];
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if ((ind0 != -1) && (ind1 != -1) && (ind2 != -1))
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{
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m_meshCurrent->addTriangle(ind0, ind1, ind2);
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}
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} // For each triangle
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}
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}
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} // For each cell
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sampler.movePositiveX();
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} // For X
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startOfRow.movePositiveY();
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} // For Y
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startOfSlice.movePositiveZ();
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} // For Z
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}
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}
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