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Initial version of mesh decimation.

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This commit is contained in:
David Williams
2008-06-10 21:45:38 +00:00
parent f8a090abba
commit 33cb721cc0
7 changed files with 324 additions and 3 deletions
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275
PolyVoxCore/source/SurfaceExtractors.cpp
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@@ -1167,4 +1167,279 @@ namespace PolyVox
}
return result;
}
void generateDecimatedMeshDataForRegion(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);
region.setUpperCorner(region.getUpperCorner() - Vector3DInt32(1,1,1));
//Offset from lower block corner
const Vector3DFloat offset = static_cast<Vector3DFloat>(region.getLowerCorner());
Vector3DFloat vertlist[12];
Vector3DFloat normlist[12];
uint8_t vertMaterials[12];
BlockVolumeIterator<boost::uint8_t> volIter(*volumeData);
volIter.setValidRegion(region);
//////////////////////////////////////////////////////////////////////////
//Get mesh data
//////////////////////////////////////////////////////////////////////////
//Iterate over each cell in the region
//volIter.setPosition(region.getLowerCorner().getX(),region.getLowerCorner().getY(), region.getLowerCorner().getZ());
for(uint16_t z = region.getLowerCorner().getZ(); z <= region.getUpperCorner().getZ(); z += 2)
{
for(uint16_t y = region.getLowerCorner().getY(); y <= region.getUpperCorner().getY(); y += 2)
{
for(uint16_t x = region.getLowerCorner().getX(); x <= region.getUpperCorner().getX(); x += 2)
{
//while(volIter.moveForwardInRegionXYZ())
//{
volIter.setPosition(x,y,z);
const uint8_t v000 = volIter.getMaxedVoxel();
volIter.setPosition(x+2,y,z);
const uint8_t v100 = volIter.getMaxedVoxel();
volIter.setPosition(x,y+2,z);
const uint8_t v010 = volIter.getMaxedVoxel();
volIter.setPosition(x+2,y+2,z);
const uint8_t v110 = volIter.getMaxedVoxel();
volIter.setPosition(x,y,z+2);
const uint8_t v001 = volIter.getMaxedVoxel();
volIter.setPosition(x+2,y,z+2);
const uint8_t v101 = volIter.getMaxedVoxel();
volIter.setPosition(x,y+2,z+2);
const uint8_t v011 = volIter.getMaxedVoxel();
volIter.setPosition(x+2,y+2,z+2);
const uint8_t v111 = volIter.getMaxedVoxel();
//Determine the index into the edge table which tells us which vertices are inside of the surface
uint8_t iCubeIndex = 0;
if (v000 == 0) iCubeIndex |= 1;
if (v100 == 0) iCubeIndex |= 2;
if (v110 == 0) iCubeIndex |= 4;
if (v010 == 0) iCubeIndex |= 8;
if (v001 == 0) iCubeIndex |= 16;
if (v101 == 0) iCubeIndex |= 32;
if (v111 == 0) iCubeIndex |= 64;
if (v011 == 0) 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)
{
vertlist[0].setX(x + 0.5f * 2.0f);
vertlist[0].setY(y);
vertlist[0].setZ(z);
normlist[0] = Vector3DFloat(v000 - v100,0.0,0.0);
vertMaterials[0] = v000 | v100; //Because one of these is 0, the or operation takes the max.
}
if (edgeTable[iCubeIndex] & 2)
{
vertlist[1].setX(x + 1.0f * 2.0f);
vertlist[1].setY(y + 0.5f * 2.0f);
vertlist[1].setZ(z);
vertMaterials[1] = v100 | v110;
normlist[1] = Vector3DFloat(0.0,v100 - v110,0.0);
}
if (edgeTable[iCubeIndex] & 4)
{
vertlist[2].setX(x + 0.5f * 2.0f);
vertlist[2].setY(y + 1.0f * 2.0f);
vertlist[2].setZ(z);
vertMaterials[2] = v010 | v110;
normlist[2] = Vector3DFloat(v010 - v110,0.0,0.0);
}
if (edgeTable[iCubeIndex] & 8)
{
vertlist[3].setX(x);
vertlist[3].setY(y + 0.5f * 2.0f);
vertlist[3].setZ(z);
vertMaterials[3] = v000 | v010;
normlist[3] = Vector3DFloat(0.0,v000 - v010,0.0);
}
if (edgeTable[iCubeIndex] & 16)
{
vertlist[4].setX(x + 0.5f * 2.0f);
vertlist[4].setY(y);
vertlist[4].setZ(z + 1.0f * 2.0f);
vertMaterials[4] = v001 | v101;
normlist[4] = Vector3DFloat(v001 - v101,0.0,0.0);
}
if (edgeTable[iCubeIndex] & 32)
{
vertlist[5].setX(x + 1.0f * 2.0f);
vertlist[5].setY(y + 0.5f * 2.0f);
vertlist[5].setZ(z + 1.0f * 2.0f);
vertMaterials[5] = v101 | v111;
normlist[5] = Vector3DFloat(0.0,v101 - v111,0.0);
}
if (edgeTable[iCubeIndex] & 64)
{
vertlist[6].setX(x + 0.5f * 2.0f);
vertlist[6].setY(y + 1.0f * 2.0f);
vertlist[6].setZ(z + 1.0f * 2.0f);
vertMaterials[6] = v011 | v111;
normlist[6] = Vector3DFloat(v011 - v111,0.0,0.0);
}
if (edgeTable[iCubeIndex] & 128)
{
vertlist[7].setX(x);
vertlist[7].setY(y + 0.5f * 2.0f);
vertlist[7].setZ(z + 1.0f * 2.0f);
vertMaterials[7] = v001 | v011;
normlist[7] = Vector3DFloat(0.0,v001 - v011,0.0);
}
if (edgeTable[iCubeIndex] & 256)
{
vertlist[8].setX(x);
vertlist[8].setY(y);
vertlist[8].setZ(z + 0.5f * 2.0f);
vertMaterials[8] = v000 | v001;
normlist[8] = Vector3DFloat(0.0,0.0,v000 - v001);
}
if (edgeTable[iCubeIndex] & 512)
{
vertlist[9].setX(x + 1.0f * 2.0f);
vertlist[9].setY(y);
vertlist[9].setZ(z + 0.5f * 2.0f);
vertMaterials[9] = v100 | v101;
normlist[9] = Vector3DFloat(0.0,0.0,v100 - v101);
}
if (edgeTable[iCubeIndex] & 1024)
{
vertlist[10].setX(x + 1.0f * 2.0f);
vertlist[10].setY(y + 1.0f * 2.0f);
vertlist[10].setZ(z + 0.5f * 2.0f);
vertMaterials[10] = v110 | v111;
normlist[10] = Vector3DFloat(0.0,0.0,v110 - v111);
}
if (edgeTable[iCubeIndex] & 2048)
{
vertlist[11].setX(x);
vertlist[11].setY(y + 1.0f * 2.0f);
vertlist[11].setZ(z + 0.5f * 2.0f);
vertMaterials[11] = v010 | v011;
normlist[11] = Vector3DFloat(0.0,0.0,v010 - v011);
}
for (int i=0;triTable[iCubeIndex][i]!=-1;i+=3)
{
//The three vertices forming a triangle
Vector3DFloat vertex0 = vertlist[triTable[iCubeIndex][i ]] - offset;
Vector3DFloat vertex1 = vertlist[triTable[iCubeIndex][i+1]] - offset;
Vector3DFloat vertex2 = vertlist[triTable[iCubeIndex][i+2]] - offset;
Vector3DFloat normal0 = normlist[triTable[iCubeIndex][i ]];
Vector3DFloat normal1 = normlist[triTable[iCubeIndex][i+1]];
Vector3DFloat normal2 = normlist[triTable[iCubeIndex][i+2]];
normal0.normalise();
normal1.normalise();
normal2.normalise();
vertex0 += (normal0);
vertex1 += (normal1);
vertex2 += (normal2);
//Cast to floats and divide by two.
//const Vector3DFloat vertex0AsFloat = (static_cast<Vector3DFloat>(vertex0) / 2.0f) - offset;
//const Vector3DFloat vertex1AsFloat = (static_cast<Vector3DFloat>(vertex1) / 2.0f) - offset;
//const Vector3DFloat vertex2AsFloat = (static_cast<Vector3DFloat>(vertex2) / 2.0f) - 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]];
//If all the materials are the same, we just need one triangle for that material with all the alphas set high.
SurfaceVertex surfaceVertex0Alpha1(vertex0,material0 + 0.1f,1.0f);
surfaceVertex0Alpha1.setNormal(normal0);
SurfaceVertex surfaceVertex1Alpha1(vertex1,material1 + 0.1f,1.0f);
surfaceVertex1Alpha1.setNormal(normal1);
SurfaceVertex surfaceVertex2Alpha1(vertex2,material2 + 0.1f,1.0f);
surfaceVertex2Alpha1.setNormal(normal2);
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 = computeNormal(volumeData, static_cast<Vector3DFloat>(iterSurfaceVertex->getPosition() + offset), SIMPLE);
const_cast<SurfaceVertex&>(*iterSurfaceVertex).setNormal(tempNormal);
++iterSurfaceVertex;
}*/
}
}
#ifdef BLAH
Vector3DFloat computeDecimatedNormal(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) - 1;
const uint16_t floorY = static_cast<uint16_t>(posY) - 1;
const uint16_t floorZ = static_cast<uint16_t>(posZ) - 1;
const uint16_t ceilX = static_cast<uint16_t>(posX) + 1;
const uint16_t ceilY = static_cast<uint16_t>(posY) + 1;
const uint16_t ceilZ = static_cast<uint16_t>(posZ) + 1;
//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 == 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;
}
#endif
}

6
PolyVoxCore/source/VolumeChangeTracker.cpp
View File

@@ -64,13 +64,13 @@ namespace PolyVox
listToFill.clear();
//Regenerate meshes.
for(uint16_t regionZ = 0; regionZ < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS; ++regionZ)
for(uint16_t regionZ = 0; regionZ < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS-1; ++regionZ)
//for(uint16_t regionZ = 0; regionZ < 1; ++regionZ)
{
for(uint16_t regionY = 0; regionY < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS; ++regionY)
for(uint16_t regionY = 0; regionY < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS-1; ++regionY)
//for(uint16_t regionY = 0; regionY < 2; ++regionY)
{
for(uint16_t regionX = 0; regionX < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS; ++regionX)
for(uint16_t regionX = 0; regionX < POLYVOX_VOLUME_SIDE_LENGTH_IN_REGIONS-1; ++regionX)
//for(uint16_t regionX = 0; regionX < 2; ++regionX)
{
if(volRegionUpToDate->getVoxelAt(regionX, regionY, regionZ) == false)