//taken from
//http://catlikecoding.com/unity/tutorials/marching-squares/
private void TriangulateCell(int i, MapElement a, MapElement b, MapElement c, MapElement d)
{
int cellType = GetCellType(a, b, c, d);
switch (cellType)
{
//simple case, no triangle
case 0:
return;
//corner case
case 1:
AddTriangle((rowCacheMin[i]), (edgeCacheMin), (rowCacheMin[i + 1]));
SetVertexHeight(innerHeightCorner, rowCacheMin[i]);
SetVertexHeight(outerHeightCorner, edgeCacheMin);
SetVertexHeight(outerHeightCorner, rowCacheMin[i + 1]);
if (Wall != null)
{
Wall.AddACAB(WallIndex(i));
}
break;
case 2:
AddTriangle((rowCacheMin[i + 2]), (rowCacheMin[i + 1]), (edgeCacheMax));
SetVertexHeight(innerHeightCorner, rowCacheMin[i + 2]);
SetVertexHeight(outerHeightCorner, rowCacheMin[i + 1]);
SetVertexHeight(outerHeightCorner, edgeCacheMax);
if (Wall != null)
{
Wall.AddABBD(WallIndex(i));
}
break;
case 4:
AddTriangle((rowCacheMax[i]), (rowCacheMax[i + 1]), (edgeCacheMin));
SetVertexHeight(innerHeightCorner, rowCacheMax[i]);
SetVertexHeight(outerHeightCorner, rowCacheMax[i + 1]);
SetVertexHeight(outerHeightCorner, edgeCacheMin);
if (Wall != null)
{
Wall.AddCDAC(WallIndex(i));
}
break;
case 8:
AddTriangle((rowCacheMax[i + 2]), (edgeCacheMax), (rowCacheMax[i + 1]));
SetVertexHeight(innerHeightCorner, rowCacheMax[i + 2]);
SetVertexHeight(outerHeightCorner, edgeCacheMax);
SetVertexHeight(outerHeightCorner, rowCacheMax[i + 1]);
if (Wall != null)
{
Wall.AddBDCD(WallIndex(i));
}
break;
//edge case
case 3:
AddQuad((rowCacheMin[i]), (edgeCacheMin), (edgeCacheMax), (rowCacheMin[i + 2]));
//top edge
SetVertexHeight(innerHeightEdge, rowCacheMin[i]);
SetVertexHeight(outerHeightEdge, edgeCacheMin);
SetVertexHeight(outerHeightEdge, edgeCacheMax);
SetVertexHeight(innerHeightEdge, rowCacheMin[i + 2]);
if (Wall != null)
{
Wall.AddACBD(WallIndex(i));
}
break;
case 5:
AddQuad((rowCacheMin[i]), (rowCacheMax[i]), (rowCacheMax[i + 1]), (rowCacheMin[i + 1]));
//right edge
SetVertexHeight(innerHeightEdge, rowCacheMin[i]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i]);
SetVertexHeight(outerHeightEdge, rowCacheMax[i + 1]);
SetVertexHeight(outerHeightEdge, rowCacheMin[i + 1]);
if (Wall != null)
{
Wall.AddCDAB(WallIndex(i));
}
break;
case 10:
AddQuad((rowCacheMin[i + 1]), (rowCacheMax[i + 1]), (rowCacheMax[i + 2]), (rowCacheMin[i + 2]));
//left edge
SetVertexHeight(outerHeightEdge, rowCacheMin[i + 1]);
SetVertexHeight(outerHeightEdge, rowCacheMax[i + 1]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i + 2]);
SetVertexHeight(innerHeightEdge, rowCacheMin[i + 2]);
if (Wall != null)
{
Wall.AddABCD(WallIndex(i));
}
break;
case 12:
AddQuad((edgeCacheMin), (rowCacheMax[i]), (rowCacheMax[i + 2]), (edgeCacheMax));
//bottom edge
SetVertexHeight(outerHeightEdge, edgeCacheMin);
SetVertexHeight(innerHeightEdge, rowCacheMax[i]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i + 2]);
SetVertexHeight(outerHeightEdge, edgeCacheMax);
if (Wall != null)
{
Wall.AddBDAC(WallIndex(i));
}
break;
//The cases with three filled and one empty voxel each require a square with a single corner cut away.
//This is basically a pentagon that's stretched out of shape.
//A pentagon can be created with five vertices and three triangles that form a small fan.
case 7:
AddPentagon((rowCacheMin[i]), (rowCacheMax[i]), (rowCacheMax[i + 1]), (edgeCacheMax), (rowCacheMin[i + 2]));
SetVertexHeight(innerHeight, rowCacheMin[i]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i]);
SetVertexHeight(outerHeightCorner, rowCacheMax[i + 1]);
SetVertexHeight(outerHeightCorner, edgeCacheMax);
SetVertexHeight(innerHeightEdge, rowCacheMin[i + 2]);
if (Wall != null)
{
Wall.AddCDBD(WallIndex(i));
}
break;
case 11:
AddPentagon((rowCacheMin[i + 2]), (rowCacheMin[i]), (edgeCacheMin), (rowCacheMax[i + 1]), (rowCacheMax[i + 2]));
SetVertexHeight(innerHeight, rowCacheMin[i + 2]);
SetVertexHeight(innerHeightEdge, rowCacheMin[i]);
SetVertexHeight(outerHeightCorner, edgeCacheMin);
SetVertexHeight(outerHeightCorner, rowCacheMax[i + 1]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i + 2]);
if (Wall != null)
{
Wall.AddACCD(WallIndex(i));
}
break;
case 13:
AddPentagon((rowCacheMax[i]), (rowCacheMax[i + 2]), (edgeCacheMax), (rowCacheMin[i + 1]), (rowCacheMin[i]));
SetVertexHeight(innerHeight, rowCacheMax[i]);
SetVertexHeight(innerHeightEdge, rowCacheMax[i + 2]);
SetVertexHeight(outerHeightCorner, edgeCacheMax);
SetVertexHeight(outerHeightCorner, rowCacheMin[i + 1]);
SetVertexHeight(innerHeightEdge, rowCacheMin[i]);
if (Wall != null)
{
Wall.AddBDAB(WallIndex(i));
}
break;
case 14:
AddPentagon((rowCacheMax[i + 2]), (rowCacheMin[i + 2]), (rowCacheMin[i + 1]), (edgeCacheMin), (rowCacheMax[i]));
SetVertexHeight(innerHeight, rowCacheMax[i + 2]);
SetVertexHeight(innerHeightEdge, rowCacheMin[i + 2]);
SetVertexHeight(outerHeightCorner, rowCacheMin[i + 1]);
SetVertexHeight(outerHeightCorner, edgeCacheMin);
SetVertexHeight(innerHeightEdge, rowCacheMax[i]);
if (Wall != null)
{
Wall.AddABAC(WallIndex(i));
}
break;
//Only the two opposite-corner cases are still missing, 6 and 9.
//I decided to disconnect them, so they require two triangles each, which you can copy from the single-triangle cases.
//Connecting them would've required a hexagon instead.
case 6:
AddTriangle((rowCacheMin[i + 2]), (rowCacheMin[i + 1]), (edgeCacheMax));
AddTriangle((rowCacheMax[i]), (rowCacheMax[i + 1]), (edgeCacheMin));
if (Wall != null)
{
Wall.AddABBD(WallIndex(i));
}
if (Wall != null)
{
Wall.AddCDAC(WallIndex(i));
}
if (Wall != null)
{
Wall.AddABAC(WallIndex(i));
}
if (Wall != null)
{
Wall.AddCDBD(WallIndex(i));
}
break;
case 9:
AddTriangle((rowCacheMin[i]), (edgeCacheMin), (rowCacheMin[i + 1]));
AddTriangle((rowCacheMax[i + 2]), (edgeCacheMax), (rowCacheMax[i + 1]));
if (Wall != null)
{
Wall.AddACAB(WallIndex(i));
}
if (Wall != null)
{
Wall.AddBDCD(WallIndex(i));
}
if (Wall != null)
{
Wall.AddBDAB(WallIndex(i));
}
if (Wall != null)
{
Wall.AddACCD(WallIndex(i));
}
break;
//center case
case 15:
AddQuad((rowCacheMin[i]), (rowCacheMax[i]), (rowCacheMax[i + 2]), (rowCacheMin[i + 2]));
SetVertexHeight(innerHeight, rowCacheMin[i]);
SetVertexHeight(innerHeight, rowCacheMax[i]);
SetVertexHeight(innerHeight, rowCacheMax[i + 2]);
SetVertexHeight(innerHeight, rowCacheMin[i + 2]);
break;
}
}
