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Initial version of mesh smoothing code.

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This commit is contained in:
David Williams
2008-06-24 21:28:29 +00:00
parent b12bd1ebe2
commit e6a7174b53
10 changed files with 167 additions and 377 deletions
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106
PolyVoxCore/source/SurfaceAdjusters.cpp
View File

@@ -1,7 +1,10 @@
#include "SurfaceAdjusters.h"
#include "BlockVolumeIterator.h"
#include "GradientEstimators.h"
#include "IndexedSurfacePatch.h"
#include "RegionGeometry.h"
#include "Utility.h"
#include <vector>
@@ -9,13 +12,110 @@ namespace PolyVox
{
void smoothRegionGeometry(BlockVolume<boost::uint8_t>* volumeData, RegionGeometry& regGeom)
{
const boost::uint8_t uSmoothingFactor = 2;
const float fThreshold = 0.5f;
BlockVolumeIterator<boost::uint8_t> volIter(*volumeData);
std::vector<SurfaceVertex>& vecVertices = regGeom.m_patchSingleMaterial->m_vecVertices;
std::vector<SurfaceVertex>::iterator iterSurfaceVertex = vecVertices.begin();
while(iterSurfaceVertex != vecVertices.end())
{
iterSurfaceVertex->setPosition(iterSurfaceVertex->getPosition() + iterSurfaceVertex->getNormal());
//iterSurfaceVertex->setPosition(iterSurfaceVertex->getPosition() + Vector3DFloat(10.0f,0.0f,0.0f));
for(int ct = 0; ct < uSmoothingFactor; ++ct)
{
const Vector3DFloat& v3dPos = iterSurfaceVertex->getPosition() + static_cast<Vector3DFloat>(regGeom.m_v3dRegionPosition);
const Vector3DInt32 v3dFloor = static_cast<Vector3DInt32>(v3dPos);
const Vector3DFloat& v3dRem = v3dPos - static_cast<Vector3DFloat>(v3dFloor);
//Check all corners are within the volume, allowing a boundary for gradient estimation
bool lowerCornerInside = volumeData->containsPoint(v3dFloor,2);
bool upperCornerInside = volumeData->containsPoint(v3dFloor+Vector3DInt32(1,1,1),2);
if(lowerCornerInside && upperCornerInside) //If this test fails the vertex will be left as it was
{
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(0,0,0)));
const float v000 = computeSmoothedVoxel(volIter);
Vector3DFloat grad000 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(1,0,0)));
const float v100 = computeSmoothedVoxel(volIter);
Vector3DFloat grad100 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(0,1,0)));
const float v010 = computeSmoothedVoxel(volIter);
Vector3DFloat grad010 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(1,1,0)));
const float v110 = computeSmoothedVoxel(volIter);
Vector3DFloat grad110 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(0,0,1)));
const float v001 = computeSmoothedVoxel(volIter);
Vector3DFloat grad001 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(1,0,1)));
const float v101 = computeSmoothedVoxel(volIter);
Vector3DFloat grad101 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(0,1,1)));
const float v011 = computeSmoothedVoxel(volIter);
Vector3DFloat grad011 = computeSmoothCentralDifferenceGradient(volIter);
volIter.setPosition(static_cast<Vector3DInt16>(v3dFloor + Vector3DInt32(1,1,1)));
const float v111 = computeSmoothedVoxel(volIter);
Vector3DFloat grad111 = computeSmoothCentralDifferenceGradient(volIter);
float fInterVal = trilinearlyInterpolate(v000,v100,v010,v110,v001,v101,v011,v111,v3dRem.getX(),v3dRem.getY(),v3dRem.getZ());
Vector3DFloat fInterGrad = trilinearlyInterpolate(grad000,grad100,grad010,grad110,grad001,grad101,grad011,grad111,v3dRem.getX(),v3dRem.getY(),v3dRem.getZ());
fInterGrad.normalise();
float fDiff = fInterVal - fThreshold;
iterSurfaceVertex->setPosition(iterSurfaceVertex->getPosition() + (fInterGrad * fDiff));
iterSurfaceVertex->setNormal(fInterGrad); //This is actually the gradient for the previous position, but it won't have moved much.
} //if(lowerCornerInside && upperCornerInside)
} //for(int ct = 0; ct < uSmoothingFactor; ++ct)
++iterSurfaceVertex;
}
} //while(iterSurfaceVertex != vecVertices.end())
}
float computeSmoothedVoxel(BlockVolumeIterator<boost::uint8_t>& volIter)
{
assert(volIter.getPosX() >= 1);
assert(volIter.getPosY() >= 1);
assert(volIter.getPosZ() >= 1);
assert(volIter.getPosX() < volIter.getVolume().getSideLength() - 2);
assert(volIter.getPosY() < volIter.getVolume().getSideLength() - 2);
assert(volIter.getPosZ() < volIter.getVolume().getSideLength() - 2);
float sum = 0.0;
if(volIter.peekVoxel1nx1ny1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx1ny0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx1ny1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx0py1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx0py0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx0py1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx1py1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx1py0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1nx1py1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1ny1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1ny0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1ny1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px0py1nz() != 0) sum += 1.0f;
if(volIter.getVoxel() != 0) sum += 1.0f;
if(volIter.peekVoxel0px0py1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1py1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1py0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel0px1py1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1ny1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1ny0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1ny1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px0py1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px0py0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px0py1pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1py1nz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1py0pz() != 0) sum += 1.0f;
if(volIter.peekVoxel1px1py1pz() != 0) sum += 1.0f;
sum /= 27.0f;
return sum;
}
}

332
PolyVoxCore/source/SurfaceExtractors.cpp
View File

@@ -32,9 +32,17 @@ namespace PolyVox
generateDecimatedMeshDataForRegion(volume.getVolumeData(), 0, *iterChangedRegions, regionGeometry.m_patchSingleMaterial);
computeNormalsForVertices(volume.getVolumeData(), regionGeometry, CENTRAL_DIFFERENCE);
//generateReferenceMeshDataForRegion(volume.getVolumeData(), *iterChangedRegions, regionGeometry.m_patchSingleMaterial);
//for(int ct = 0; ct < 2; ct++)
Vector3DInt32 temp = regionGeometry.m_v3dRegionPosition;
//temp /= 16;
if(temp.getX() % 32 == 0)
{
smoothRegionGeometry(volume.getVolumeData(), regionGeometry);
}
//smoothRegionGeometry(volume.getVolumeData(), regionGeometry);
//computeNormalsForVertices(volume.getVolumeData(), regionGeometry, CENTRAL_DIFFERENCE);
//genMultiFromSingle(regionGeometry.m_patchSingleMaterial, regionGeometry.m_patchMultiMaterial);
@@ -746,324 +754,4 @@ namespace PolyVox
}
}*/
}
void generateSmoothMeshDataForRegion(BlockVolume<uint8_t>* volumeData, Region region, IndexedSurfacePatch* singleMaterialPatch)
{
//When generating the mesh for a region we actually look one voxel outside it in the
// back, bottom, right direction. Protect against access violations by cropping region here
Region regVolume = volumeData->getEnclosingRegion();
regVolume.setUpperCorner(regVolume.getUpperCorner() - Vector3DInt32(1,1,1));
region.cropTo(regVolume);
//Offset from lower block corner
const Vector3DFloat offset = static_cast<Vector3DFloat>(region.getLowerCorner());
Vector3DFloat vertlist[12];
uint8_t vertMaterials[12];
BlockVolumeIterator<boost::uint8_t> volIter(*volumeData);
volIter.setValidRegion(region);
const float threshold = 0.5f;
//////////////////////////////////////////////////////////////////////////
//Get mesh data
//////////////////////////////////////////////////////////////////////////
//Iterate over each cell in the region
for(volIter.setPosition(region.getLowerCorner().getX(),region.getLowerCorner().getY(), region.getLowerCorner().getZ());volIter.isValidForRegion();volIter.moveForwardInRegionXYZ())
{
//Current position
const uint16_t x = volIter.getPosX();
const uint16_t y = volIter.getPosY();
const uint16_t z = volIter.getPosZ();
//Voxels values
BlockVolumeIterator<boost::uint8_t> tempVolIter(*volumeData);
tempVolIter.setPosition(x,y,z);
const float v000 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x+1,y,z);
const float v100 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x,y+1,z);
const float v010 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x+1,y+1,z);
const float v110 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x,y,z+1);
const float v001 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x+1,y,z+1);
const float v101 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x,y+1,z+1);
const float v011 = tempVolIter.getAveragedVoxel(1);
tempVolIter.setPosition(x+1,y+1,z+1);
const float v111 = tempVolIter.getAveragedVoxel(1);
//Determine the index into the edge table which tells us which vertices are inside of the surface
uint8_t iCubeIndex = 0;
if (v000 < threshold) iCubeIndex |= 1;
if (v100 < threshold) iCubeIndex |= 2;
if (v110 < threshold) iCubeIndex |= 4;
if (v010 < threshold) iCubeIndex |= 8;
if (v001 < threshold) iCubeIndex |= 16;
if (v101 < threshold) iCubeIndex |= 32;
if (v111 < threshold) iCubeIndex |= 64;
if (v011 < threshold) iCubeIndex |= 128;
/* Cube is entirely in/out of the surface */
if (edgeTable[iCubeIndex] == 0)
{
continue;
}
/* Find the vertices where the surface intersects the cube */
if (edgeTable[iCubeIndex] & 1)
{
float a = v000;
float b = v100;
float val = (threshold-a)/(b-a);
vertlist[0].setX(x + val);
vertlist[0].setY(y);
vertlist[0].setZ(z);
vertMaterials[0] = 1;//v000 | v100; //Because one of these is 0, the or operation takes the max.
}
if (edgeTable[iCubeIndex] & 2)
{
float a = v100;
float b = v110;
float val = (threshold-a)/(b-a);
vertlist[1].setX(x + 1.0f);
vertlist[1].setY(y + val);
vertlist[1].setZ(z);
vertMaterials[1] = 1;//v100 | v110;
}
if (edgeTable[iCubeIndex] & 4)
{
float a = v010;
float b = v110;
float val = (threshold-a)/(b-a);
vertlist[2].setX(x + val);
vertlist[2].setY(y + 1.0f);
vertlist[2].setZ(z);
vertMaterials[2] = 1;//v010 | v110;
}
if (edgeTable[iCubeIndex] & 8)
{
float a = v000;
float b = v010;
float val = (threshold-a)/(b-a);
vertlist[3].setX(x);
vertlist[3].setY(y + val);
vertlist[3].setZ(z);
vertMaterials[3] = 1;//v000 | v010;
}
if (edgeTable[iCubeIndex] & 16)
{
float a = v001;
float b = v101;
float val = (threshold-a)/(b-a);
vertlist[4].setX(x + val);
vertlist[4].setY(y);
vertlist[4].setZ(z + 1.0f);
vertMaterials[4] = 1;//v001 | v101;
}
if (edgeTable[iCubeIndex] & 32)
{
float a = v101;
float b = v111;
float val = (threshold-a)/(b-a);
vertlist[5].setX(x + 1.0f);
vertlist[5].setY(y + val);
vertlist[5].setZ(z + 1.0f);
vertMaterials[5] = 1;//v101 | v111;
}
if (edgeTable[iCubeIndex] & 64)
{
float a = v011;
float b = v111;
float val = (threshold-a)/(b-a);
vertlist[6].setX(x + val);
vertlist[6].setY(y + 1.0f);
vertlist[6].setZ(z + 1.0f);
vertMaterials[6] = 1;//v011 | v111;
}
if (edgeTable[iCubeIndex] & 128)
{
float a = v001;
float b = v011;
float val = (threshold-a)/(b-a);
vertlist[7].setX(x);
vertlist[7].setY(y + val);
vertlist[7].setZ(z + 1.0f);
vertMaterials[7] = 1;//v001 | v011;
}
if (edgeTable[iCubeIndex] & 256)
{
float a = v000;
float b = v001;
float val = (threshold-a)/(b-a);
vertlist[8].setX(x);
vertlist[8].setY(y);
vertlist[8].setZ(z + val);
vertMaterials[8] = 1;//v000 | v001;
}
if (edgeTable[iCubeIndex] & 512)
{
float a = v100;
float b = v101;
float val = (threshold-a)/(b-a);
vertlist[9].setX(x + 1.0f);
vertlist[9].setY(y);
vertlist[9].setZ(z + val);
vertMaterials[9] = 1;//v100 | v101;
}
if (edgeTable[iCubeIndex] & 1024)
{
float a = v110;
float b = v111;
float val = (threshold-a)/(b-a);
vertlist[10].setX(x + 1.0f);
vertlist[10].setY(y + 1.0f);
vertlist[10].setZ(z + val);
vertMaterials[10] = 1;//v110 | v111;
}
if (edgeTable[iCubeIndex] & 2048)
{
float a = v010;
float b = v011;
float val = (threshold-a)/(b-a);
vertlist[11].setX(x);
vertlist[11].setY(y + 1.0f);
vertlist[11].setZ(z + val);
vertMaterials[11] = 1;//v010 | v011;
}
for (int i=0;triTable[iCubeIndex][i]!=-1;i+=3)
{
//The three vertices forming a triangle
const Vector3DFloat vertex0 = vertlist[triTable[iCubeIndex][i ]] - offset;
const Vector3DFloat vertex1 = vertlist[triTable[iCubeIndex][i+1]] - offset;
const Vector3DFloat vertex2 = vertlist[triTable[iCubeIndex][i+2]] - offset;
const uint8_t material0 = vertMaterials[triTable[iCubeIndex][i ]];
const uint8_t material1 = vertMaterials[triTable[iCubeIndex][i+1]];
const uint8_t material2 = vertMaterials[triTable[iCubeIndex][i+2]];
SurfaceVertex surfaceVertex0Alpha1(vertex0,material0 + 0.1f,1.0f);
SurfaceVertex surfaceVertex1Alpha1(vertex1,material1 + 0.1f,1.0f);
SurfaceVertex surfaceVertex2Alpha1(vertex2,material2 + 0.1f,1.0f);
singleMaterialPatch->addTriangle(surfaceVertex0Alpha1, surfaceVertex1Alpha1, surfaceVertex2Alpha1);
}//For each triangle
}//For each cell
//FIXME - can it happen that we have no vertices or triangles? Should exit early?
//for(std::map<uint8_t, IndexedSurfacePatch*>::iterator iterPatch = surfacePatchMapResult.begin(); iterPatch != surfacePatchMapResult.end(); ++iterPatch)
{
std::vector<SurfaceVertex>::iterator iterSurfaceVertex = singleMaterialPatch->getVertices().begin();
while(iterSurfaceVertex != singleMaterialPatch->getVertices().end())
{
Vector3DFloat tempNormal = computeSmoothNormal(volumeData, static_cast<Vector3DFloat>(iterSurfaceVertex->getPosition() + offset), CENTRAL_DIFFERENCE);
const_cast<SurfaceVertex&>(*iterSurfaceVertex).setNormal(tempNormal);
++iterSurfaceVertex;
}
}
}
Vector3DFloat computeSmoothNormal(BlockVolume<uint8_t>* volumeData, const Vector3DFloat& position, NormalGenerationMethod normalGenerationMethod)
{
const float posX = position.getX();
const float posY = position.getY();
const float posZ = position.getZ();
const uint16_t floorX = static_cast<uint16_t>(posX);
const uint16_t floorY = static_cast<uint16_t>(posY);
const uint16_t floorZ = static_cast<uint16_t>(posZ);
//Check all corners are within the volume, allowing a boundary for gradient estimation
bool lowerCornerInside = volumeData->containsPoint(Vector3DInt32(floorX, floorY, floorZ),1);
bool upperCornerInside = volumeData->containsPoint(Vector3DInt32(floorX+1, floorY+1, floorZ+1),1);
if((!lowerCornerInside) || (!upperCornerInside))
{
normalGenerationMethod = SIMPLE;
}
Vector3DFloat result;
BlockVolumeIterator<boost::uint8_t> volIter(*volumeData); //FIXME - save this somewhere - could be expensive to create?
if(normalGenerationMethod == SOBEL)
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ));
const Vector3DFloat gradFloor = computeSobelGradient(volIter);
if((posX - floorX) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX+1.0),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ));
}
if((posY - floorY) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY+1.0),static_cast<uint16_t>(posZ));
}
if((posZ - floorZ) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ+1.0));
}
const Vector3DFloat gradCeil = computeSobelGradient(volIter);
result = ((gradFloor + gradCeil) * -1.0f);
if(result.lengthSquared() < 0.0001)
{
//Operation failed - fall back on simple gradient estimation
normalGenerationMethod = SIMPLE;
}
}
if(normalGenerationMethod == CENTRAL_DIFFERENCE)
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ));
const Vector3DFloat gradFloor = computeSmoothCentralDifferenceGradient(volIter);
if((posX - floorX) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX+1.0),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ));
}
if((posY - floorY) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY+1.0),static_cast<uint16_t>(posZ));
}
if((posZ - floorZ) > 0.25) //The result should be 0.0 or 0.5
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ+1.0));
}
const Vector3DFloat gradCeil = computeSmoothCentralDifferenceGradient(volIter);
result = ((gradFloor + gradCeil) * -1.0f);
if(result.lengthSquared() < 0.0001)
{
//Operation failed - fall back on simple gradient estimation
normalGenerationMethod = SIMPLE;
}
}
if(normalGenerationMethod == SIMPLE)
{
volIter.setPosition(static_cast<uint16_t>(posX),static_cast<uint16_t>(posY),static_cast<uint16_t>(posZ));
const uint8_t uFloor = volIter.getVoxel() > 0 ? 1 : 0;
if((posX - floorX) > 0.25) //The result should be 0.0 or 0.5
{
uint8_t uCeil = volIter.peekVoxel1px0py0pz() > 0 ? 1 : 0;
result = Vector3DFloat(static_cast<float>(uFloor - uCeil),0.0,0.0);
}
else if((posY - floorY) > 0.25) //The result should be 0.0 or 0.5
{
uint8_t uCeil = volIter.peekVoxel0px1py0pz() > 0 ? 1 : 0;
result = Vector3DFloat(0.0,static_cast<float>(uFloor - uCeil),0.0);
}
else if((posZ - floorZ) > 0.25) //The result should be 0.0 or 0.5
{
uint8_t uCeil = volIter.peekVoxel0px0py1pz() > 0 ? 1 : 0;
result = Vector3DFloat(0.0, 0.0,static_cast<float>(uFloor - uCeil));
}
}
return result;
}
}