public static void GenerateRegularCell(Util.GridCell cell, List <Vector3> vertices, List <int> triangles, 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 (Tables.edgeTable[cubeindex] == 0)
{
return;
}
/* Find the vertices where the surface intersects the cube */
if ((Tables.edgeTable[cubeindex] & 1) == 1)
{
vertlist[0] = UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[1]);
}
if ((Tables.edgeTable[cubeindex] & 2) == 2)
{
vertlist[1] = UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]);
}
if ((Tables.edgeTable[cubeindex] & 4) == 4)
{
vertlist[2] = UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[3]);
}
if ((Tables.edgeTable[cubeindex] & 8) == 8)
{
vertlist[3] = UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]);
}
if ((Tables.edgeTable[cubeindex] & 16) == 16)
{
vertlist[4] = UtilFuncs.Lerp(isovalue, cell.points[4], cell.points[5]);
}
if ((Tables.edgeTable[cubeindex] & 32) == 32)
{
vertlist[5] = UtilFuncs.Lerp(isovalue, cell.points[5], cell.points[6]);
}
if ((Tables.edgeTable[cubeindex] & 64) == 64)
{
vertlist[6] = UtilFuncs.Lerp(isovalue, cell.points[6], cell.points[7]);
}
if ((Tables.edgeTable[cubeindex] & 128) == 128)
{
vertlist[7] = UtilFuncs.Lerp(isovalue, cell.points[7], cell.points[4]);
}
if ((Tables.edgeTable[cubeindex] & 256) == 256)
{
vertlist[8] = UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[4]);
}
if ((Tables.edgeTable[cubeindex] & 512) == 512)
{
vertlist[9] = UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[5]);
}
if ((Tables.edgeTable[cubeindex] & 1024) == 1024)
{
vertlist[10] = UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[6]);
}
if ((Tables.edgeTable[cubeindex] & 2048) == 2048)
{
vertlist[11] = UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[7]);
}
/* Create the triangle */
ntriang = 0;
for (i = 0; Tables.triTable[cubeindex][i] != -1; i += 3)
{
ntriang++;
}
for (i = 0; Tables.triTable[cubeindex][i] != -1; i++)
{
triangles.Add(vertices.Count);
vertices.Add(vertlist[Tables.triTable[cubeindex][i]]);
}
}
public static void PolyganiseTetrahedron(Util.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(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
break;
case 0x02:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
break;
case 0x04:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[1]));
break;
case 0x08:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
break;
case 0x03:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
break;
case 0x05:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[3]));
break;
case 0x09:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
break;
case 0x06:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[2]));
break;
case 0x0C:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[1]));
break;
case 0x0A:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
break;
case 0x07:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[3], cell.points[1]));
break;
case 0x0B:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[2], cell.points[0]));
break;
case 0x0D:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[0]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[3]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[1], cell.points[2]));
break;
case 0x0E:
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[1]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[2]));
vertices.Add(UtilFuncs.Lerp(isovalue, cell.points[0], cell.points[3]));
break;
}
}