private Vector3D getNormal(FaceIndices face)
{
Vector3D v10 = Point3D.Subtract(this.meshVertices[face.Indices[0]], this.meshVertices[face.Indices[1]]);
Vector3D v12 = Point3D.Subtract(this.meshVertices[face.Indices[2]], this.meshVertices[face.Indices[1]]);
var normal = Vector3D.CrossProduct(v12, v10);
normal.Normalize();
return(normal);
}
//triangulate a cell
private FaceIndices[] CellToFaces(Cell cell)
{
try
{
Index index = this._host.cellularFloor.FindIndex(cell);
int k = 0;
Cell nextI = this._host.cellularFloor.RelativeIndex(index, new Index(1, 0));
if (nextI != null)
{
if (this.cellToValue.ContainsKey(nextI))
{
k++;
}
else
{
nextI = null;
}
}
Cell nextJ = this._host.cellularFloor.RelativeIndex(index, new Index(0, 1));
if (nextJ != null)
{
if (this.cellToValue.ContainsKey(nextJ))
{
k++;
}
else
{
nextJ = null;
}
}
Cell nextIJ = this._host.cellularFloor.RelativeIndex(index, new Index(1, 1));
if (nextIJ != null)
{
if (this.cellToValue.ContainsKey(nextIJ))
{
k++;
}
else
{
nextIJ = null;
}
}
if (k < 2)//there are only two points
{
return(null);
}
if (k == 2)//there are three points
{
Point3D[] pnts = new Point3D[3];
pnts[0] = this.point3DAndCell.Find(cell);
int i = 1;
if (nextI != null)
{
pnts[i] = this.point3DAndCell.Find(nextI);
i++;
}
if (nextJ != null)
{
pnts[i] = this.point3DAndCell.Find(nextJ);
i++;
}
if (nextIJ != null)
{
pnts[i] = this.point3DAndCell.Find(nextIJ);
i++;
}
int v0 = this.Point3DAndIndex.Find(pnts[0]);
int v1 = this.Point3DAndIndex.Find(pnts[1]);
int v2 = this.Point3DAndIndex.Find(pnts[2]);
FaceIndices[] face = new FaceIndices[1];
face[0] = new FaceIndices(v0, v1, v2);
Vector3D vec10 = Point3D.Subtract(pnts[0], pnts[1]);
Vector3D vec12 = Point3D.Subtract(pnts[2], pnts[1]);
var normal = Vector3D.CrossProduct(vec12, vec10);
if (normal.Z < 0)
{
face[0].Flip();
}
return(face);
}
//there are four points
FaceIndices[] faces = new FaceIndices[2];
Point3D v00 = this.point3DAndCell.Find(cell);
int I00 = this.Point3DAndIndex.Find(v00);
Point3D v10 = this.point3DAndCell.Find(nextI);
int I10 = this.Point3DAndIndex.Find(v10);
Point3D v11 = this.point3DAndCell.Find(nextIJ);
int I11 = this.Point3DAndIndex.Find(v11);
Point3D v01 = this.point3DAndCell.Find(nextJ);
int I01 = this.Point3DAndIndex.Find(v01);
faces[0] = new FaceIndices(I00, I10, I11);
faces[1] = new FaceIndices(I00, I11, I01);
return(faces);
}
catch (Exception error)
{
MessageBox.Show(error.Message);
}
return(null);
}