private static void PolygonizeCell(Vector3i pos, sbyte[] density, MeshBuilder mesh, int lod)
{
byte directionMask = (byte)((pos.x > 0 ? 1 : 0) | ((pos.z > 0 ? 1 : 0) << 1) | ((pos.y > 0 ? 1 : 0) << 2));
byte caseCode = GetCaseCode(density);
if ((caseCode ^ ((density[7] >> 7) & 0xFF)) == 0) //for this cases there is no triangulation
{
return;
}
byte regularCellClass = Tables.RegularCellClass[caseCode];
ushort[] vertexLocations = Tables.RegularVertexData[caseCode];
Tables.RegularCell c = Tables.RegularCellData[regularCellClass];
long vertexCount = c.GetVertexCount();
long triangleCount = c.GetTriangleCount();
byte[] indexOffset = c.GetIndices(); // index offsets for current cell
int[] mappedIndices = new int[indexOffset.Length];
for (int i = 0; i < vertexCount; ++i)
{
byte edge = (byte)(vertexLocations[i] >> 8);
byte reuseIndex = (byte)(edge & 0xF); // vertex id which should be created or reused 1,2 or 3
byte rDir = (byte)(edge >> 4); // the direction to go to reach a previous cell for reusing
byte v0 = (byte)((vertexLocations[i] >> 4) & 0x0F); // first corner index
byte v1 = (byte)((vertexLocations[i]) & 0x0F); // second corner index
sbyte d0 = density[v0];
sbyte d1 = density[v1];
Debug.Assert(v1 > v0);
int t = (d1 << 8) / (d1 - d0);
int u = 0x0100 - t;
float t0 = t / 256f;
float t1 = u / 256f;
int index = -1;
// todo: try the caching stuff later
if (index == -1)
{
Vector3 p0 = new Vector3(
pos.x + Tables.vertexOffset[v0, 0],
pos.y + Tables.vertexOffset[v0, 1],
pos.z + Tables.vertexOffset[v0, 2]);
Vector3 p1 = new Vector3(
pos.x + Tables.vertexOffset[v1, 0],
pos.y + Tables.vertexOffset[v1, 1],
pos.z + Tables.vertexOffset[v1, 2]);
mesh.AddVertex(InterpolateVoxelVector(t, p0, p1));
}
mappedIndices[i] = index;
}
}
