AnotherFoxGuy/polyvox
1
0
Fork 0
Code Issues Pull Requests Activity

Work on experimental version of marching cubes algorithm. Now bitmasks are precomputed.

Browse Source
This commit is contained in:
David Williams 2008-06-03 20:49:42 +00:00
parent e49859fc40
commit 4c98f9579b
1 changed files with 33 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
source/SurfaceExtractors.cpp
View File

@ -62,11 +62,15 @@ namespace PolyVox
memset(vertexIndicesY,0xFF,sizeof(vertexIndicesY));
memset(vertexIndicesZ,0xFF,sizeof(vertexIndicesZ));
//Cell bitmasks
boost::uint8_t bitmask[POLYVOX_REGION_SIDE_LENGTH+1][POLYVOX_REGION_SIDE_LENGTH+1][POLYVOX_REGION_SIDE_LENGTH+1];
memset(bitmask, 0x00, sizeof(bitmask));
std::vector<boost::uint32_t> vecTriangleIndices;
std::vector<SurfaceVertex> vecVertices;
//////////////////////////////////////////////////////////////////////////
//Get mesh data
// Compute bitmasks
//////////////////////////////////////////////////////////////////////////
//Iterate over each cell in the region
@ -101,6 +105,30 @@ namespace PolyVox
if (v111 == 0) iCubeIndex |= 64;
if (v011 == 0) iCubeIndex |= 128;
//Save the bitmask
bitmask[x][y][z] = iCubeIndex;
}//For each cell
//////////////////////////////////////////////////////////////////////////
//Get mesh data
//////////////////////////////////////////////////////////////////////////
//Iterate over each cell in the region
volIter.setPosition(region.getLowerCorner().getX(),region.getLowerCorner().getY(), region.getLowerCorner().getZ());
volIter.setValidRegion(region);
while(volIter.moveForwardInRegionXYZ())
{
//Current position
const uint16_t x = volIter.getPosX() - offset.getX();
const uint16_t y = volIter.getPosY() - offset.getY();
const uint16_t z = volIter.getPosZ() - offset.getZ();
const uint8_t v000 = volIter.getVoxel();
//Determine the index into the edge table which tells us which vertices are inside of the surface
uint8_t iCubeIndex = bitmask[x][y][z];
/* Cube is entirely in/out of the surface */
if (edgeTable[iCubeIndex] == 0)
{
@ -115,7 +143,7 @@ namespace PolyVox
vertlist[0].setX(x + 0.5f);
vertlist[0].setY(y);
vertlist[0].setZ(z);
vertMaterials[0] = v000 | v100; //Because one of these is 0, the or operation takes the max.
vertMaterials[0] = v000 | volIter.peekVoxel1px0py0pz(); //Because one of these is 0, the or operation takes the max.
SurfaceVertex surfaceVertex(vertlist[0],vertMaterials[0], 1.0);
vecVertices.push_back(surfaceVertex);
vertexIndicesX[x][y][z] = vecVertices.size()-1;
@ -142,7 +170,7 @@ namespace PolyVox
vertlist[3].setX(x);
vertlist[3].setY(y + 0.5f);
vertlist[3].setZ(z);
vertMaterials[3] = v000 | v010;
vertMaterials[3] = v000 | volIter.peekVoxel0px1py0pz();
SurfaceVertex surfaceVertex(vertlist[3],vertMaterials[3], 1.0);
vecVertices.push_back(surfaceVertex);
vertexIndicesY[x][y][z] = vecVertices.size()-1;
@ -183,7 +211,7 @@ namespace PolyVox
vertlist[8].setX(x);
vertlist[8].setY(y);
vertlist[8].setZ(z + 0.5f);
vertMaterials[8] = v000 | v001;
vertMaterials[8] = v000 | volIter.peekVoxel0px0py1pz();
SurfaceVertex surfaceVertex(vertlist[8],vertMaterials[8], 1.0);
vecVertices.push_back(surfaceVertex);
vertexIndicesZ[x][y][z] = vecVertices.size()-1;
@ -241,27 +269,8 @@ namespace PolyVox
const uint16_t y = volIter.getPosY() - offset.getY();
const uint16_t z = volIter.getPosZ() - offset.getZ();
//Voxels values
const uint8_t v000 = volIter.getVoxel();
const uint8_t v100 = volIter.peekVoxel1px0py0pz();
const uint8_t v010 = volIter.peekVoxel0px1py0pz();
const uint8_t v110 = volIter.peekVoxel1px1py0pz();
const uint8_t v001 = volIter.peekVoxel0px0py1pz();
const uint8_t v101 = volIter.peekVoxel1px0py1pz();
const uint8_t v011 = volIter.peekVoxel0px1py1pz();
const uint8_t v111 = volIter.peekVoxel1px1py1pz();
//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;
uint8_t iCubeIndex = bitmask[x][y][z];
/* Cube is entirely in/out of the surface */
if (edgeTable[iCubeIndex] == 0)