public Mesh GenLodCell(WorldChunk<sbyte> chunk)
{
Mesh mesh = new Mesh();
int lod = 1;
for (int x = 0; x < volume.ChunkSize; x++)
{
for (int y = 0; y < volume.ChunkSize; y++)
{
for (int z = 0; z < volume.ChunkSize; z++)
{
Vector3i position; //new Vector3i(x, y, z);
position.X = x;
position.Y = y;
position.Z = z;
PolygonizeCell(chunk.GetPosition(), position, ref mesh, lod);
}
}
}
return mesh;
}
internal void PolygonizeCell(Vector3i offsetPos, Vector3i pos, ref Mesh mesh, int lod)
{
Debug.Assert(lod >= 1, "Level of Detail must be greater than 1");
offsetPos += pos * lod;
byte directionMask = (byte)((pos.X > 0 ? 1 : 0) | ((pos.Z > 0 ? 1 : 0) << 1) | ((pos.Y > 0 ? 1 : 0) << 2));
sbyte[] density = new sbyte[8];
for (int i = 0; i < density.Length; i++)
{
density[i] = volume[offsetPos + Tables.CornerIndex[i] * lod];
}
byte caseCode = getCaseCode(density);
if ((caseCode ^ ((density[7] >> 7) & 0xFF)) == 0) //for this cases there is no triangulation
return;
Vector3f[] cornerNormals = new Vector3f[8];
for (int i = 0; i < 8; i++)
{
var p = offsetPos + Tables.CornerIndex[i] * lod;
float nx = (volume[p + Vector3i.UnitX] - volume[p - Vector3i.UnitX]) * 0.5f;
float ny = (volume[p + Vector3i.UnitY] - volume[p - Vector3i.UnitY]) * 0.5f;
float nz = (volume[p + Vector3i.UnitZ] - volume[p - Vector3i.UnitZ]) * 0.5f;
//cornerNormals[i] = new Vector3f(nx, ny, nz);
cornerNormals[i].X = nx;
cornerNormals[i].Y = ny;
cornerNormals[i].Z = nz;
cornerNormals[i].Normalize();
}
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.Indizes(); //index offsets for current cell
ushort[] mappedIndizes = new ushort[indexOffset.Length]; //array with real indizes for current cell
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 v1 = (byte)((vertexLocations[i]) & 0x0F); //Second Corner Index
byte v0 = (byte)((vertexLocations[i] >> 4) & 0x0F); //First Corner Index
sbyte d0 = density[v0];
sbyte d1 = density[v1];
//Vector3f n0 = cornerNormals[v0];
//Vector3f n1 = cornerNormals[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;
if (UseCache && v1 != 7 && (rDir & directionMask) == rDir)
{
Debug.Assert(reuseIndex != 0);
ReuseCell cell = cache.GetReusedIndex(pos, rDir);
index = cell.Verts[reuseIndex];
}
if (index == -1)
{
Vector3f normal = cornerNormals[v0] * t0 + cornerNormals[v1] * t1;
GenerateVertex(ref offsetPos, ref pos, mesh, lod, t, ref v0, ref v1, ref d0, ref d1, normal);
index = mesh.LatestAddedVertIndex();
}
if ((rDir & 8) != 0)
{
cache.SetReusableIndex(pos, reuseIndex, mesh.LatestAddedVertIndex());
}
mappedIndizes[i] = (ushort)index;
}
for (int t = 0; t < triangleCount; t++)
{
for (int i = 0; i < 3; i++)
{
mesh.AddIndex(mappedIndizes[c.Indizes()[t * 3 + i]]);
}
}
}
private void GenerateVertex(ref Vector3i offsetPos, ref Vector3i pos, Mesh mesh, int lod, long t, ref byte v0, ref byte v1, ref sbyte d0, ref sbyte d1, Vector3f normal)
{
Vector3i iP0 = (offsetPos + Tables.CornerIndex[v0] * lod);
Vector3f P0;// = new Vector3f(iP0.X, iP0.Y, iP0.Z);
P0.X = iP0.X;
P0.Y = iP0.Y;
P0.Z = iP0.Z;
Vector3i iP1 = (offsetPos + Tables.CornerIndex[v1] * lod);
Vector3f P1;// = new Vector3f(iP1.X, iP1.Y, iP1.Z);
P1.X = iP1.X;
P1.Y = iP1.Y;
P1.Z = iP1.Z;
//EliminateLodPositionShift(lod, ref d0, ref d1, ref t, ref iP0, ref P0, ref iP1, ref P1);
Vector3f Q = InterpolateVoxelVector(t, P0, P1);
mesh.AddVertex(Q, normal);
}
