public static void Polyganise(Strucs.GridCell cell, List <Vector3> vertices, float isovalue)
{
Vector3[] vertlist = new Vector3[12];
int i, ntriang;
int cubeindex;
cubeindex = 0;
if (cell.Points[0].Density < isovalue)
{
cubeindex |= 1;
}
if (cell.Points[1].Density < isovalue)
{
cubeindex |= 2;
}
if (cell.Points[2].Density < isovalue)
{
cubeindex |= 4;
}
if (cell.Points[3].Density < isovalue)
{
cubeindex |= 8;
}
if (cell.Points[4].Density < isovalue)
{
cubeindex |= 16;
}
if (cell.Points[5].Density < isovalue)
{
cubeindex |= 32;
}
if (cell.Points[6].Density < isovalue)
{
cubeindex |= 64;
}
if (cell.Points[7].Density < isovalue)
{
cubeindex |= 128;
}
/* Cube is entirely in/out of the surface */
if (edgeTable[cubeindex] == 0)
{
return;
}
/* Find the vertices where the surface intersects the cube */
if ((edgeTable[cubeindex] & 1) == 1)
{
vertlist[0] = Utility.Lerp(isovalue, cell.Points[0], cell.Points[1]);
}
if ((edgeTable[cubeindex] & 2) == 2)
{
vertlist[1] = Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]);
}
if ((edgeTable[cubeindex] & 4) == 4)
{
vertlist[2] = Utility.Lerp(isovalue, cell.Points[2], cell.Points[3]);
}
if ((edgeTable[cubeindex] & 8) == 8)
{
vertlist[3] = Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]);
}
if ((edgeTable[cubeindex] & 16) == 16)
{
vertlist[4] = Utility.Lerp(isovalue, cell.Points[4], cell.Points[5]);
}
if ((edgeTable[cubeindex] & 32) == 32)
{
vertlist[5] = Utility.Lerp(isovalue, cell.Points[5], cell.Points[6]);
}
if ((edgeTable[cubeindex] & 64) == 64)
{
vertlist[6] = Utility.Lerp(isovalue, cell.Points[6], cell.Points[7]);
}
if ((edgeTable[cubeindex] & 128) == 128)
{
vertlist[7] = Utility.Lerp(isovalue, cell.Points[7], cell.Points[4]);
}
if ((edgeTable[cubeindex] & 256) == 256)
{
vertlist[8] = Utility.Lerp(isovalue, cell.Points[0], cell.Points[4]);
}
if ((edgeTable[cubeindex] & 512) == 512)
{
vertlist[9] = Utility.Lerp(isovalue, cell.Points[1], cell.Points[5]);
}
if ((edgeTable[cubeindex] & 1024) == 1024)
{
vertlist[10] = Utility.Lerp(isovalue, cell.Points[2], cell.Points[6]);
}
if ((edgeTable[cubeindex] & 2048) == 2048)
{
vertlist[11] = Utility.Lerp(isovalue, cell.Points[3], cell.Points[7]);
}
/* Create the triangle */
ntriang = 0;
for (i = 0; triTable[cubeindex][i] != -1; i += 3)
{
ntriang++;
}
for (i = 0; triTable[cubeindex][i] != -1; i++)
{
vertices.Add(vertlist[triTable[cubeindex][i]]);
}
}
public static void PolyganiseTetrahedron(Strucs.GridCell cell, List <Vector3> vertices, float isovalue)
{
int triangleIndex = 0;
if (cell.Points[0].Density < isovalue)
{
triangleIndex |= 1;
}
if (cell.Points[1].Density < isovalue)
{
triangleIndex |= 2;
}
if (cell.Points[2].Density < isovalue)
{
triangleIndex |= 4;
}
if (cell.Points[3].Density < isovalue)
{
triangleIndex |= 8;
}
// these cases were taken from https://github.com/Calvin-L/MarchingTetrahedrons/blob/master/Decimate.cpp
switch (triangleIndex)
{
case 0:
case 15:
break;
case 0x01:
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
break;
case 0x02:
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
break;
case 0x04:
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[1]));
break;
case 0x08:
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
break;
case 0x03:
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
break;
case 0x05:
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[3]));
break;
case 0x09:
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
break;
case 0x06:
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[2]));
break;
case 0x0C:
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[1]));
break;
case 0x0A:
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
break;
case 0x07:
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[3], cell.Points[1]));
break;
case 0x0B:
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[2], cell.Points[0]));
break;
case 0x0D:
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[0]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[3]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[1], cell.Points[2]));
break;
case 0x0E:
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[1]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[2]));
vertices.Add(Utility.Lerp(isovalue, cell.Points[0], cell.Points[3]));
break;
}
}