e89a55d154
I didn't apply the changes to a few macro-heavy files as Visual Studio removes all indentation from macros, whereas the indentation can be handy to see nesting.
461 lines
25 KiB
C++
461 lines
25 KiB
C++
/*******************************************************************************
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* The MIT License (MIT)
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*
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* Copyright (c) 2015 David Williams and Matthew Williams
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*******************************************************************************/
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#include "Impl/Timer.h"
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namespace PolyVox
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{
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template< typename Sampler, typename ControllerType>
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Vector3DFloat computeCentralDifferenceGradient(const Sampler& volIter, ControllerType& controller)
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{
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//FIXME - Should actually use DensityType here, both in principle and because the maths may be
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//faster (and to reduce casts). So it would be good to add a way to get DensityType from a voxel.
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//But watch out for when the DensityType is unsigned and the difference could be negative.
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float voxel1nx = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx0py0pz()));
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float voxel1px = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px0py0pz()));
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float voxel1ny = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1ny0pz()));
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float voxel1py = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1py0pz()));
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float voxel1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px0py1nz()));
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float voxel1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px0py1pz()));
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return Vector3DFloat
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(
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voxel1nx - voxel1px,
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voxel1ny - voxel1py,
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voxel1nz - voxel1pz
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);
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}
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// This 'sobel' version of gradient estimation provides better (smoother) normals than the central difference version.
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// Even with the 16-bit normal encoding it does seem to make a difference, so is probably worth keeping. However, there
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// is no way to call it at the moment beyond modifying the main Marching Cubes function below to call this function
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// instead of the central difference one. We should provide a way to control the normal generation method, perhaps
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// including *no* normals incase the user wants to generate them afterwards (e.g. from the mesh).
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template< typename Sampler, typename ControllerType>
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Vector3DFloat computeSobelGradient(const Sampler& volIter, ControllerType& controller)
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{
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static const int weights[3][3][3] = { { { 2, 3, 2 }, { 3, 6, 3 }, { 2, 3, 2 } }, {
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{ 3, 6, 3 }, { 6, 0, 6 }, { 3, 6, 3 } }, { { 2, 3, 2 }, { 3, 6, 3 }, { 2, 3, 2 } } };
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//FIXME - Should actually use DensityType here, both in principle and because the maths may be
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//faster (and to reduce casts). So it would be good to add a way to get DensityType from a voxel.
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//But watch out for when the DensityType is unsigned and the difference could be negative.
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const float pVoxel1nx1ny1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1ny1nz()));
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const float pVoxel1nx1ny0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1ny0pz()));
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const float pVoxel1nx1ny1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1ny1pz()));
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const float pVoxel1nx0py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx0py1nz()));
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const float pVoxel1nx0py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx0py0pz()));
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const float pVoxel1nx0py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx0py1pz()));
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const float pVoxel1nx1py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1py1nz()));
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const float pVoxel1nx1py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1py0pz()));
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const float pVoxel1nx1py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1nx1py1pz()));
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const float pVoxel0px1ny1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1ny1nz()));
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const float pVoxel0px1ny0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1ny0pz()));
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const float pVoxel0px1ny1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1ny1pz()));
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const float pVoxel0px0py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px0py1nz()));
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//const float pVoxel0px0py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px0py0pz()));
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const float pVoxel0px0py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px0py1pz()));
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const float pVoxel0px1py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1py1nz()));
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const float pVoxel0px1py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1py0pz()));
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const float pVoxel0px1py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel0px1py1pz()));
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const float pVoxel1px1ny1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1ny1nz()));
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const float pVoxel1px1ny0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1ny0pz()));
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const float pVoxel1px1ny1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1ny1pz()));
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const float pVoxel1px0py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px0py1nz()));
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const float pVoxel1px0py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px0py0pz()));
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const float pVoxel1px0py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px0py1pz()));
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const float pVoxel1px1py1nz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1py1nz()));
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const float pVoxel1px1py0pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1py0pz()));
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const float pVoxel1px1py1pz = static_cast<float>(controller.convertToDensity(volIter.peekVoxel1px1py1pz()));
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const float xGrad(-weights[0][0][0] * pVoxel1nx1ny1nz -
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weights[1][0][0] * pVoxel1nx1ny0pz - weights[2][0][0] *
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pVoxel1nx1ny1pz - weights[0][1][0] * pVoxel1nx0py1nz -
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weights[1][1][0] * pVoxel1nx0py0pz - weights[2][1][0] *
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pVoxel1nx0py1pz - weights[0][2][0] * pVoxel1nx1py1nz -
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weights[1][2][0] * pVoxel1nx1py0pz - weights[2][2][0] *
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pVoxel1nx1py1pz + weights[0][0][2] * pVoxel1px1ny1nz +
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weights[1][0][2] * pVoxel1px1ny0pz + weights[2][0][2] *
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pVoxel1px1ny1pz + weights[0][1][2] * pVoxel1px0py1nz +
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weights[1][1][2] * pVoxel1px0py0pz + weights[2][1][2] *
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pVoxel1px0py1pz + weights[0][2][2] * pVoxel1px1py1nz +
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weights[1][2][2] * pVoxel1px1py0pz + weights[2][2][2] *
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pVoxel1px1py1pz);
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const float yGrad(-weights[0][0][0] * pVoxel1nx1ny1nz -
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weights[1][0][0] * pVoxel1nx1ny0pz - weights[2][0][0] *
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pVoxel1nx1ny1pz + weights[0][2][0] * pVoxel1nx1py1nz +
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weights[1][2][0] * pVoxel1nx1py0pz + weights[2][2][0] *
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pVoxel1nx1py1pz - weights[0][0][1] * pVoxel0px1ny1nz -
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weights[1][0][1] * pVoxel0px1ny0pz - weights[2][0][1] *
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pVoxel0px1ny1pz + weights[0][2][1] * pVoxel0px1py1nz +
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weights[1][2][1] * pVoxel0px1py0pz + weights[2][2][1] *
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pVoxel0px1py1pz - weights[0][0][2] * pVoxel1px1ny1nz -
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weights[1][0][2] * pVoxel1px1ny0pz - weights[2][0][2] *
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pVoxel1px1ny1pz + weights[0][2][2] * pVoxel1px1py1nz +
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weights[1][2][2] * pVoxel1px1py0pz + weights[2][2][2] *
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pVoxel1px1py1pz);
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const float zGrad(-weights[0][0][0] * pVoxel1nx1ny1nz +
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weights[2][0][0] * pVoxel1nx1ny1pz - weights[0][1][0] *
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pVoxel1nx0py1nz + weights[2][1][0] * pVoxel1nx0py1pz -
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weights[0][2][0] * pVoxel1nx1py1nz + weights[2][2][0] *
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pVoxel1nx1py1pz - weights[0][0][1] * pVoxel0px1ny1nz +
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weights[2][0][1] * pVoxel0px1ny1pz - weights[0][1][1] *
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pVoxel0px0py1nz + weights[2][1][1] * pVoxel0px0py1pz -
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weights[0][2][1] * pVoxel0px1py1nz + weights[2][2][1] *
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pVoxel0px1py1pz - weights[0][0][2] * pVoxel1px1ny1nz +
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weights[2][0][2] * pVoxel1px1ny1pz - weights[0][1][2] *
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pVoxel1px0py1nz + weights[2][1][2] * pVoxel1px0py1pz -
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weights[0][2][2] * pVoxel1px1py1nz + weights[2][2][2] *
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pVoxel1px1py1pz);
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//Note: The above actually give gradients going from low density to high density.
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//For our normals we want the the other way around, so we switch the components as we return them.
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return Vector3DFloat(-xGrad, -yGrad, -zGrad);
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}
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template< typename VolumeType, typename MeshType, typename ControllerType >
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void extractMarchingCubesMeshCustom(VolumeType* volData, Region region, MeshType* result, ControllerType controller)
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{
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// Validate parameters
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POLYVOX_THROW_IF(volData == nullptr, std::invalid_argument, "Provided volume cannot be null");
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POLYVOX_THROW_IF(result == nullptr, std::invalid_argument, "Provided mesh cannot be null");
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// For profiling this function
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Timer timer;
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// Performance note: Profiling indicates that simply adding vertices and indices to the std::vector is one
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// of the bottlenecks when generating the mesh. Reserving space in advance helps here but is wasteful in the
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// common case that no/few vertices are generated. Maybe it's worth reserving a couple of thousand or so?
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// Alternatively, maybe the docs should suggest the user reserves some space in the mesh they pass in?
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result->clear();
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// Store some commonly used values for performance and convienience
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const uint32_t uRegionWidthInVoxels = region.getWidthInVoxels();
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const uint32_t uRegionHeightInVoxels = region.getHeightInVoxels();
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const uint32_t uRegionDepthInVoxels = region.getDepthInVoxels();
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typename ControllerType::DensityType tThreshold = controller.getThreshold();
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// A naive implemetation of Marching Cubes might sample the eight corner voxels of every cell to determine the cell index.
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// However, when processing the cells sequentially we cn observe that many of the voxels are shared with previous adjacent
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// cells, and so we can obtain these by careful bit-shifting. These variables keep track of previous cells for this purpose.
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// We don't clear the arrays because the algorithm ensures that we only read from elements we have previously written to.
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uint8_t uPreviousCellIndex = 0;
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Array1DUint8 pPreviousRowCellIndices(uRegionWidthInVoxels);
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Array2DUint8 pPreviousSliceCellIndices(uRegionWidthInVoxels, uRegionHeightInVoxels);
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// A given vertex may be shared by multiple triangles, so we need to keep track of the indices into the vertex array.
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// We don't clear the arrays because the algorithm ensures that we only read from elements we have previously written to.
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Array<2, Vector3DInt32> pIndices(uRegionWidthInVoxels, uRegionHeightInVoxels);
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Array<2, Vector3DInt32> pPreviousIndices(uRegionWidthInVoxels, uRegionHeightInVoxels);
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// A sampler pointing at the beginning of the region, which gets incremented to always point at the beginning of a slice.
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typename VolumeType::Sampler startOfSlice(volData);
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startOfSlice.setPosition(region.getLowerX(), region.getLowerY(), region.getLowerZ());
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for (uint32_t uZRegSpace = 0; uZRegSpace < uRegionDepthInVoxels; uZRegSpace++)
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{
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// A sampler pointing at the beginning of the slice, which gets incremented to always point at the beginning of a row.
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typename VolumeType::Sampler startOfRow = startOfSlice;
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for (uint32_t uYRegSpace = 0; uYRegSpace < uRegionHeightInVoxels; uYRegSpace++)
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{
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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 (uint32_t uXRegSpace = 0; uXRegSpace < uRegionWidthInVoxels; uXRegSpace++)
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{
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// Note: In many cases the provided region will be (mostly) empty which means mesh vertices/indices
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// are not generated and the only thing that is done for each cell is the computation of uCellIndex.
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// It appears that retriving the voxel value is not so expensive and that it is the bitwise combining
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// which actually carries the cost.
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//
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// If we really need to speed this up more then it may be possible to pack 4 8-bit cell indices into
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// a single 32-bit value and then perform the bitwise logic on all four of them at the same time.
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// However, this complicates the code and there would still be the cost of packing/unpacking so it's
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// not clear if there is really a benefit. It's something to consider in the future.
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// Each bit of the cell index specifies whether a given corner of the cell is above or below the threshold.
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uint8_t uCellIndex = 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 uPreviousCellIndexZ = pPreviousSliceCellIndices(uXRegSpace, uYRegSpace);
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uPreviousCellIndexZ >>= 4;
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uCellIndex |= uPreviousCellIndexZ;
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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 uPreviousCellIndexY = pPreviousRowCellIndices(uXRegSpace);
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uPreviousCellIndexY &= 204; //204 = 128+64+8+4
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uPreviousCellIndexY >>= 2;
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uCellIndex |= uPreviousCellIndexY;
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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 UPreviousCellIndexX = uPreviousCellIndex;
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UPreviousCellIndexX &= 170; //170 = 128+32+8+2
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UPreviousCellIndexX >>= 1;
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uCellIndex |= UPreviousCellIndexX;
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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 (controller.convertToDensity(v111) < tThreshold) uCellIndex |= 128;
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// The current value becomes the previous value, ready for the next iteration.
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uPreviousCellIndex = uCellIndex;
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pPreviousRowCellIndices(uXRegSpace) = uCellIndex;
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pPreviousSliceCellIndices(uXRegSpace, uYRegSpace) = uCellIndex;
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// 12 bits of uEdge determine whether a vertex is placed on each of the 12 edges of the cell.
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uint16_t uEdge = edgeTable[uCellIndex];
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// Test whether any vertices and indices should be generated for the current cell (i.e. it is occupied).
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// Performance note: This condition is usually false because most cells in a volume are completely above
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// or below the threshold and hence unoccupied. However, even when it is always false (testing on an empty
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// volume) it still incurs significant overhead, probably because the code is large and bloats the for loop
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// which contains it. On my empty volume test case the code as given runs in 34ms, but if I replace the
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// condition with 'false' it runs in 24ms and gives the same output (i.e. none).
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//
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// An improvement is to move the code into a seperate function which does speed things up (30ms), but this
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// is messy as the function needs to be passed about 10 differnt parameters, probably adding some overhead
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// in its self. This does indeed seem to slow down the case when cells are occupied, by about 10-20%.
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//
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// Overall I don't know the right solution, but I'm leaving the code as-is to avoid making it messy. If we
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// can reduce the number of parameters which need to be passed then it might be worth moving it into a
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// function, or otherwise it may simply be worth trying to shorten the code (e.g. adding other function
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// calls). For now we will leave it as-is, until we have more information from real-world profiling.
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if (uEdge != 0)
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{
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auto v111Density = controller.convertToDensity(v111);
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// Performance note: Computing normals is one of the bottlencks in the mesh generation process. The
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// central difference approach actually samples the same voxel more than once as we call it on two
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// adjacent voxels. Perhaps we could expand this and eliminate dupicates in the future. Alternatively,
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// we could compute vertex normals from adjacent face normals instead of via central differencing,
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// but not for vertices on the edge of the region (as this causes visual discontinities).
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const Vector3DFloat n111 = computeCentralDifferenceGradient(sampler, controller);
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/* Find the vertices where the surface intersects the cube */
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if ((uEdge & 64) && (uXRegSpace > 0))
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{
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sampler.moveNegativeX();
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typename VolumeType::VoxelType v011 = sampler.getVoxel();
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auto v011Density = controller.convertToDensity(v011);
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const float fInterp = static_cast<float>(tThreshold - v011Density) / static_cast<float>(v111Density - v011Density);
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// Compute the position
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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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// Compute the normal
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const Vector3DFloat n011 = computeCentralDifferenceGradient(sampler, controller);
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Vector3DFloat v3dNormal = (n111*fInterp) + (n011*(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 = controller.blendMaterials(v011, v111, fInterp);
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MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
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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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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 = result->addVertex(surfaceVertex);
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pIndices(uXRegSpace, uYRegSpace).setX(uLastVertexIndex);
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sampler.movePositiveX();
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}
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if ((uEdge & 32) && (uYRegSpace > 0))
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{
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sampler.moveNegativeY();
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typename VolumeType::VoxelType v101 = sampler.getVoxel();
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auto v101Density = controller.convertToDensity(v101);
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const float fInterp = static_cast<float>(tThreshold - v101Density) / static_cast<float>(v111Density - v101Density);
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// Compute the position
|
|
const Vector3DFloat v3dPosition(static_cast<float>(uXRegSpace), static_cast<float>(uYRegSpace - 1) + fInterp, static_cast<float>(uZRegSpace));
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|
|
|
// Compute the normal
|
|
const Vector3DFloat n101 = computeCentralDifferenceGradient(sampler, controller);
|
|
Vector3DFloat v3dNormal = (n111*fInterp) + (n101*(1 - fInterp));
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|
|
|
// The gradient for a voxel can be zero (e.g. solid voxel surrounded by empty ones) and so
|
|
// the interpolated normal can also be zero (e.g. a grid of alternating solid and empty voxels).
|
|
if (v3dNormal.lengthSquared() > 0.000001f)
|
|
{
|
|
v3dNormal.normalise();
|
|
}
|
|
|
|
// Allow the controller to decide how the material should be derived from the voxels.
|
|
const typename VolumeType::VoxelType uMaterial = controller.blendMaterials(v101, v111, fInterp);
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|
|
|
MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
|
|
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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|
surfaceVertex.encodedPosition = v3dScaledPosition;
|
|
surfaceVertex.encodedNormal = encodeNormal(v3dNormal);
|
|
surfaceVertex.data = uMaterial;
|
|
|
|
uint32_t uLastVertexIndex = result->addVertex(surfaceVertex);
|
|
pIndices(uXRegSpace, uYRegSpace).setY(uLastVertexIndex);
|
|
|
|
sampler.movePositiveY();
|
|
}
|
|
if ((uEdge & 1024) && (uZRegSpace > 0))
|
|
{
|
|
sampler.moveNegativeZ();
|
|
typename VolumeType::VoxelType v110 = sampler.getVoxel();
|
|
auto v110Density = controller.convertToDensity(v110);
|
|
const float fInterp = static_cast<float>(tThreshold - v110Density) / static_cast<float>(v111Density - v110Density);
|
|
|
|
// Compute the position
|
|
const Vector3DFloat v3dPosition(static_cast<float>(uXRegSpace), static_cast<float>(uYRegSpace), static_cast<float>(uZRegSpace - 1) + fInterp);
|
|
|
|
// Compute the normal
|
|
const Vector3DFloat n110 = computeCentralDifferenceGradient(sampler, controller);
|
|
Vector3DFloat v3dNormal = (n111*fInterp) + (n110*(1 - fInterp));
|
|
|
|
// The gradient for a voxel can be zero (e.g. solid voxel surrounded by empty ones) and so
|
|
// the interpolated normal can also be zero (e.g. a grid of alternating solid and empty voxels).
|
|
if (v3dNormal.lengthSquared() > 0.000001f)
|
|
{
|
|
v3dNormal.normalise();
|
|
}
|
|
|
|
// Allow the controller to decide how the material should be derived from the voxels.
|
|
const typename VolumeType::VoxelType uMaterial = controller.blendMaterials(v110, v111, fInterp);
|
|
|
|
MarchingCubesVertex<typename VolumeType::VoxelType> surfaceVertex;
|
|
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));
|
|
surfaceVertex.encodedPosition = v3dScaledPosition;
|
|
surfaceVertex.encodedNormal = encodeNormal(v3dNormal);
|
|
surfaceVertex.data = uMaterial;
|
|
|
|
const uint32_t uLastVertexIndex = result->addVertex(surfaceVertex);
|
|
pIndices(uXRegSpace, uYRegSpace).setZ(uLastVertexIndex);
|
|
|
|
sampler.movePositiveZ();
|
|
}
|
|
|
|
// Now output the indices. For the first row, column or slice there aren't
|
|
// any (the region size in cells is one less than the region size in voxels)
|
|
if ((uXRegSpace != 0) && (uYRegSpace != 0) && (uZRegSpace != 0))
|
|
{
|
|
|
|
int32_t indlist[12];
|
|
|
|
/* Find the vertices where the surface intersects the cube */
|
|
if (uEdge & 1)
|
|
{
|
|
indlist[0] = pPreviousIndices(uXRegSpace, uYRegSpace - 1).getX();
|
|
}
|
|
if (uEdge & 2)
|
|
{
|
|
indlist[1] = pPreviousIndices(uXRegSpace, uYRegSpace).getY();
|
|
}
|
|
if (uEdge & 4)
|
|
{
|
|
indlist[2] = pPreviousIndices(uXRegSpace, uYRegSpace).getX();
|
|
}
|
|
if (uEdge & 8)
|
|
{
|
|
indlist[3] = pPreviousIndices(uXRegSpace - 1, uYRegSpace).getY();
|
|
}
|
|
if (uEdge & 16)
|
|
{
|
|
indlist[4] = pIndices(uXRegSpace, uYRegSpace - 1).getX();
|
|
}
|
|
if (uEdge & 32)
|
|
{
|
|
indlist[5] = pIndices(uXRegSpace, uYRegSpace).getY();
|
|
}
|
|
if (uEdge & 64)
|
|
{
|
|
indlist[6] = pIndices(uXRegSpace, uYRegSpace).getX();
|
|
}
|
|
if (uEdge & 128)
|
|
{
|
|
indlist[7] = pIndices(uXRegSpace - 1, uYRegSpace).getY();
|
|
}
|
|
if (uEdge & 256)
|
|
{
|
|
indlist[8] = pIndices(uXRegSpace - 1, uYRegSpace - 1).getZ();
|
|
}
|
|
if (uEdge & 512)
|
|
{
|
|
indlist[9] = pIndices(uXRegSpace, uYRegSpace - 1).getZ();
|
|
}
|
|
if (uEdge & 1024)
|
|
{
|
|
indlist[10] = pIndices(uXRegSpace, uYRegSpace).getZ();
|
|
}
|
|
if (uEdge & 2048)
|
|
{
|
|
indlist[11] = pIndices(uXRegSpace - 1, uYRegSpace).getZ();
|
|
}
|
|
|
|
for (int i = 0; triTable[uCellIndex][i] != -1; i += 3)
|
|
{
|
|
const int32_t ind0 = indlist[triTable[uCellIndex][i]];
|
|
const int32_t ind1 = indlist[triTable[uCellIndex][i + 1]];
|
|
const int32_t ind2 = indlist[triTable[uCellIndex][i + 2]];
|
|
|
|
if ((ind0 != -1) && (ind1 != -1) && (ind2 != -1))
|
|
{
|
|
result->addTriangle(ind0, ind1, ind2);
|
|
}
|
|
} // For each triangle
|
|
}
|
|
} // For each cell
|
|
sampler.movePositiveX();
|
|
} // For X
|
|
startOfRow.movePositiveY();
|
|
} // For Y
|
|
startOfSlice.movePositiveZ();
|
|
|
|
pIndices.swap(pPreviousIndices);
|
|
} // For Z
|
|
|
|
result->setOffset(region.getLowerCorner());
|
|
|
|
POLYVOX_LOG_TRACE("Marching cubes surface extraction took ", timer.elapsedTimeInMilliSeconds(),
|
|
"ms (Region size = ", region.getWidthInVoxels(), "x", region.getHeightInVoxels(),
|
|
"x", region.getDepthInVoxels(), ")");
|
|
}
|
|
}
|