public Face[] CreateFaces(int count)
{
Face[] buff = new Face[count];
for (int i = 0; i < count; i++)
buff[i] = CreateFace();
return buff;
}
public Face CreateFace()
{
Face f = new Face();
Faces.Add(f);
f.OwnerMesh = this;
return f;
}
public void Clip2d(Face face_a, Face face_b, out List<Face> a_only, out Face overlap)
{
a_only = new List<Face>();
overlap = null;
}
public void TransferFaceTo(Face f, Mesh mesh)
{
if (mesh.Shape != Shape)
throw new System.ApplicationException("Can not transfer faces between shapes");
//transfer the face
Faces.Remove(f);
mesh.Faces.Add(f);
f.OwnerMesh = mesh;
//go over each edge in the face and copy it over
for(int edgeidx = 0; edgeidx < f.Edges.Count; edgeidx++)
{
//get the edge and remove the face from it
Edge e = f.Edges[edgeidx];
e.OwnerFaces.Remove(f);
//create a new edge and replace it
Edge newedge = mesh.CreateEdge();
newedge.OwnerFaces.Add(f);
f.Edges[edgeidx] = newedge;
//set the 2 vertex references
newedge.SetVertex(0, e.Vertices[0]);
newedge.SetVertex(1, e.Vertices[1]);
}
}
public void SplitByRay(Point3D raystart, Vector3D raydir, out Face inside_face, out Face outside_face)
{
//default to just returning this as inside and outside
inside_face = this;
outside_face = null;
raydir.Normalize();
if (!Scene.NextStage("SplitByRay"))
return;
else if (Scene.IsCurrentStage())
Scene.AddDebugLine(raystart-raydir*10,raystart+raydir*10);
//get the edges, feature info and params that describe how the ray intersects the face
Edge edge0, edge1;
double param0, param1;
MathUtils.RayLineResult res0, res1;
GetRaySplitParams(raystart, raydir, out edge0, out param0, out res0, out edge1, out param1, out res1);
//debug draw the results
if (Scene.IsCurrentStage())
{
if(res0 == MathUtils.RayLineResult.INTERSECTING_LINE)
Scene.AddDebugLine(edge0.Vertices[0].Pos,edge0.Vertices[1].Pos);
else if(res0 == MathUtils.RayLineResult.INTERSECTING_POS0)
Scene.AddDebugCross(edge0.Vertices[0].Pos, 0.5);
else if (res0 == MathUtils.RayLineResult.PARALLEL_OVERLAPPING)
{
Scene.AddDebugCross(edge0.Vertices[0].Pos, 0.5);
Scene.AddDebugCross(edge0.Vertices[1].Pos, 0.5);
}
if (res1 == MathUtils.RayLineResult.INTERSECTING_LINE)
Scene.AddDebugLine(edge1.Vertices[0].Pos, edge1.Vertices[1].Pos);
else if (res1 == MathUtils.RayLineResult.INTERSECTING_POS0)
Scene.AddDebugCross(edge1.Vertices[0].Pos, 0.5);
else if (res1 == MathUtils.RayLineResult.PARALLEL_OVERLAPPING)
{
Scene.AddDebugCross(edge1.Vertices[1].Pos, 0.5);
Scene.AddDebugCross(edge1.Vertices[1].Pos, 0.5);
}
}
//check if centre is initially inside ray
Vector3D centre_offset = Centre - raystart;
double centre_cp = MathUtils.CrossXY(centre_offset, raydir);
//valid results for closed, convex, clockwise polygon are:
// res0 == no intersection res1 == no intersection
//when res0 is parallel:
// res0 == parallel overlapping res1 == intersecting pos0 of next edge (this is treated as no intersection as there is no split required)
// res0 == parallel overlapping res1 == parallel overlapping next edge IF next edge is colinear
//when res0 is vertex cases
// res0 == intersecting pos0 of first edge res1 == parallel overlapping last edge (note: in any other scenario res0 would detect the parallel line, and res1 will be the vertex)
// res0 == intersecting pos0 of any edge res1 == no intersection (i.e. we just touched 1 vertex)
// res0 == intersecting pos0 of any edge res1 == intersecting pos0 of any none-neighour edge
// res0 == intersecting pos0 of any edge res1 == intersecting line of any edge other than previous neighbour
//when res0 is line cases
// res0 == intersecting line of any edge res1 == intersecting pos0 of any edge other than next neighbour
// res0 == intersecting line of any edge res1 == intersecting line of any edge
//check intersection results for each valid combination of res0 and res1
if (res0 == MathUtils.RayLineResult.PARALLEL_OVERLAPPING)
{
//first edge is both parallel and overlapping the ray, so just return this face as left or right
if (edge1 != NextEdge(edge0))
throw new System.ApplicationException("If res0 is parallel, expected res1 to be the next edge");
if (res1 == MathUtils.RayLineResult.PARALLEL_OVERLAPPING)
{
if(Math.Abs(1-Vector3D.DotProduct(edge0.Direction,edge1.Direction)) > MathUtils.EPSILON)
throw new System.ApplicationException("If res0 is parallel and res1 is parallel, res1 must be colinear");
//pick side and return
if (centre_cp <= 0)
inside_face = this;
}
else if (res1 == MathUtils.RayLineResult.INTERSECTING_POS0)
{
//pick side and return
if (centre_cp <= 0)
inside_face = this;
}
else
{
throw new System.ApplicationException("If res0 is parallel, expected res1 must be overlapping (if colinear) or pos0");
}
}
else if (res0 == MathUtils.RayLineResult.INTERSECTING_POS0)
{
//first edge overlaps its starting vertex
if (res1 == MathUtils.RayLineResult.UNKOWN)
{
//no intersection (we just clipped the first vertex of edge0) - still pick side and return?
if (centre_cp <= 0)
inside_face = this;
}
else if(res1 == MathUtils.RayLineResult.INTERSECTING_POS0)
{
if(edge1 == NextEdge(edge0) || edge1 == PrevEdge(edge0))
throw new System.ApplicationException("If res0 is pos0 and res1 is pos0, edge1 must not be neighbour of edge0");
//got intersection - need to do vertex-vertex split
Face newface = Split(edge0, edge1);
Vector3D new_centre_offset = Centre - raystart;
double new_centre_cp = MathUtils.CrossXY(new_centre_offset, raydir);
if (new_centre_cp <= 0)
{
inside_face = this;
outside_face = newface;
}
else
{
outside_face = this;
inside_face = newface;
}
}
else if (res1 == MathUtils.RayLineResult.INTERSECTING_LINE)
{
if (edge1 == PrevEdge(edge0))
throw new System.ApplicationException("If res0 is pos0 and res1 is line, edge1 must not be neighbour of edge0");
//got intersection - need to do vertex-edge split
Face newface = Split(edge0, edge1, param1);
Vector3D new_centre_offset = Centre - raystart;
double new_centre_cp = MathUtils.CrossXY(new_centre_offset, raydir);
if (new_centre_cp <= 0)
{
inside_face = this;
outside_face = newface;
}
else
{
outside_face = this;
inside_face = newface;
}
}
else if (res1 == MathUtils.RayLineResult.PARALLEL_OVERLAPPING)
{
if (edge1 != Edges.Last())
throw new System.ApplicationException("If res1 is parallel, expected it to be the last edge");
if (edge0 != Edges.First())
throw new System.ApplicationException("If res1 is parallel, expected res0 to be the first edge");
//pick side and return
if (centre_cp <= 0)
inside_face = this;
}
else
{
throw new System.ApplicationException("If res0 is pos0, res1 must be none, pos0 or line");
}
}
else if (res0 == MathUtils.RayLineResult.INTERSECTING_LINE)
{
//first edge is overlaps the line
if (res1 == MathUtils.RayLineResult.INTERSECTING_POS0)
{
if (edge1 == NextEdge(edge0))
throw new System.ApplicationException("If res0 is line, edge1 must not be next neighbour of edge0");
//got intersection - need to do edge-vertex split
Face newface = Split(edge0, param0, edge1);
Vector3D new_centre_offset = Centre - raystart;
double new_centre_cp = MathUtils.CrossXY(new_centre_offset, raydir);
if (new_centre_cp <= 0)
{
inside_face = this;
outside_face = newface;
}
else
{
outside_face = this;
inside_face = newface;
}
}
else if (res1 == MathUtils.RayLineResult.INTERSECTING_LINE)
{
//got intersection - need to do edge-edge split
Face newface = Split(edge0, param0, edge1, param1);
Vector3D new_centre_offset = Centre - raystart;
double new_centre_cp = MathUtils.CrossXY(new_centre_offset, raydir);
if (new_centre_cp <= 0)
{
inside_face = this;
outside_face = newface;
}
else
{
outside_face = this;
inside_face = newface;
}
}
else
{
throw new System.ApplicationException("If res0 is line, res1 must be pos or line");
}
}
else
{
if (res1 != MathUtils.RayLineResult.UNKOWN)
throw new System.ApplicationException("If res0 is no intersection, res1 should also be no intersection");
//no intersection at all - still pick side and return?
if (centre_cp <= 0)
inside_face = this;
}
}
