private VertexList GenerateVertexList(VoxelCorners <float> voxelDensities, VoxelCorners <int3> voxelCorners,
int edgeIndex, float isolevel)
{
var vertexList = new VertexList();
for (int i = 0; i < 12; i++)
{
if ((edgeIndex & (1 << i)) == 0)
{
continue;
}
int edgeStartIndex = LookupTables.EdgeIndexTable[2 * i + 0];
int edgeEndIndex = LookupTables.EdgeIndexTable[2 * i + 1];
int3 corner1 = voxelCorners[edgeStartIndex];
int3 corner2 = voxelCorners[edgeEndIndex];
float density1 = voxelDensities[edgeStartIndex];
float density2 = voxelDensities[edgeEndIndex];
vertexList[i] = VertexInterpolate(corner1, corner2, density1, density2, isolevel);
}
return(vertexList);
}
private VoxelCorners <int3> GetCorners(int3 position)
{
VoxelCorners <int3> corners = new VoxelCorners <int3>();
for (int i = 0; i < 8; i++)
{
corners[i] = position + LookupTables.CubeCorners[i];
}
return(corners);
}
private VoxelCorners <float> GetDensities(int3 localPosition)
{
VoxelCorners <float> densities = new VoxelCorners <float>();
for (int i = 0; i < 8; i++)
{
int3 voxelCorner = localPosition + LookupTables.CubeCorners[i];
int densityIndex = voxelCorner.x * (chunkSize + 1) * (chunkSize + 1) + voxelCorner.y * (chunkSize + 1) + voxelCorner.z;
densities[i] = this.densities[densityIndex];
}
return(densities);
}
/// <summary>
/// The execute method required by the Unity Job System's IJobParallelFor
/// </summary>
/// <param name="index">The iteration index</param>
public void Execute(int index)
{
// Voxel's position inside the chunk. Goes from (0, 0, 0) to (chunkSize-1, chunkSize-1, chunkSize-1)
int3 voxelLocalPosition = new int3(
index / (chunkSize * chunkSize),
index / chunkSize % chunkSize,
index % chunkSize);
VoxelCorners <float> densities = GetDensities(voxelLocalPosition);
int cubeIndex = CalculateCubeIndex(densities, isolevel);
if (cubeIndex == 0 || cubeIndex == 255)
{
return;
}
VoxelCorners <int3> corners = GetCorners(voxelLocalPosition);
int edgeIndex = LookupTables.EdgeTable[cubeIndex];
VertexList vertexList = GenerateVertexList(densities, corners, edgeIndex, isolevel);
// Index at the beginning of the row
int rowIndex = 15 * cubeIndex;
for (int i = 0; LookupTables.TriangleTable[rowIndex + i] != -1 && i < 15; i += 3)
{
int triangleIndex = counter.Increment() * 3;
vertices[triangleIndex + 0] = vertexList[LookupTables.TriangleTable[rowIndex + i + 0]];
triangles[triangleIndex + 0] = triangleIndex + 0;
vertices[triangleIndex + 1] = vertexList[LookupTables.TriangleTable[rowIndex + i + 1]];
triangles[triangleIndex + 1] = triangleIndex + 1;
vertices[triangleIndex + 2] = vertexList[LookupTables.TriangleTable[rowIndex + i + 2]];
triangles[triangleIndex + 2] = triangleIndex + 2;
}
}
private int CalculateCubeIndex(VoxelCorners <float> voxelDensities, float isolevel)
{
int cubeIndex = 0;
if (voxelDensities.Corner1 < isolevel)
{
cubeIndex |= 1;
}
if (voxelDensities.Corner2 < isolevel)
{
cubeIndex |= 2;
}
if (voxelDensities.Corner3 < isolevel)
{
cubeIndex |= 4;
}
if (voxelDensities.Corner4 < isolevel)
{
cubeIndex |= 8;
}
if (voxelDensities.Corner5 < isolevel)
{
cubeIndex |= 16;
}
if (voxelDensities.Corner6 < isolevel)
{
cubeIndex |= 32;
}
if (voxelDensities.Corner7 < isolevel)
{
cubeIndex |= 64;
}
if (voxelDensities.Corner8 < isolevel)
{
cubeIndex |= 128;
}
return(cubeIndex);
}