public static Shape Rectangle(Vector3D size)
{
Shape s = new Shape();
Mesh m = s.CreateConvex();
Face f = m.CreateFace(4);
Vector3D halfsize = size * 0.5;
f.Vertices[0].Pos = new Point3D(-halfsize.X, -halfsize.Y, 0);
f.Vertices[1].Pos = new Point3D(-halfsize.X, halfsize.Y, 0);
f.Vertices[2].Pos = new Point3D(halfsize.X, halfsize.Y, 0);
f.Vertices[3].Pos = new Point3D(halfsize.X, -halfsize.Y, 0);
return(s);
}
public Face Split(Edge edge0, Edge edge1)
{
//get indices
int idx0 = Edges.IndexOf(edge0);
int idx1 = Edges.IndexOf(edge1);
//verify indices
if (idx0 == idx1)
{
throw new System.ApplicationException("Can not split face between 2 vertices");
}
if (((idx0 + 1) % Edges.Count) == idx1)
{
throw new System.ApplicationException("Edge 1 is next edge after edge 0 - edges must be at least 1 vertex apart");
}
if (((idx1 + 1) % Edges.Count) == idx0)
{
throw new System.ApplicationException("Edge 0 is next edge after edge 1 - edges must be at least 1 vertex apart");
}
//we have a list of edges in the face, and are transferring those between edge0 and edge1 to new face
//so if keeping 'a' on this face, and transfer 'b' to new face
//will be in one of these 2 orders, depending on which comes first - edge0 or edge1
//b-b-b-e1-a-a-a-e0-b-b-b
//a-a-a-e0-b-b-b-e1-a-a-a
//so, check indices to work out if edge0 comes first or edge1 comes first
List <Edge> my_edges, other_edges;
if (idx0 < idx1)
{
//edge0 is first, so have:
//a-a-a-e0-b-b-b-e1-a-a-a
//after splitting it should be:
//a-a-a-e0(b)-b-b-b-e1(a)-a-a-a
my_edges = Edges.Skip(idx0).Take(idx1 - idx0).ToList();
other_edges = Edges.Skip(idx1).Concat(Edges.Take(idx0)).ToList();
}
else
{
//edge1 is first, so have:
//b-b-b-e1-a-a-a-e0-b-b-b
//after splitting it should be:
//b-b-b-e1(a)-a-a-a-e0(b)-b-b-b
other_edges = Edges.Skip(idx1).Take(idx0 - idx1).ToList();
my_edges = Edges.Skip(idx0).Concat(Edges.Take(idx1)).ToList();
}
//store new list of edges (effectively linking face->edge for all edges we keep)
Edges = my_edges;
//creatre new face
Face new_face = OwnerMesh.CreateFace();
//transfer all other edges from this face to new face
foreach (Edge e in other_edges)
{
e.OwnerFaces.Remove(this); //unlink edge->face (face->edge was automatically unlinked when changed edge list)
new_face.AddEdge(e); //add edge to new face (adds it to list, linking edge->face and face->edge)
RemoveVertex(e.Vertices[0]); //unlink vertex0<->face
new_face.AddVertex(e.Vertices[0]); //link vertex0<->newface
}
//add last vertex in other face tot the other face
new_face.AddVertex(other_edges.Last().Vertices[1]);
//re-add just the first vert in the other face, which will have been incorrectly removed from this one
AddVertex(other_edges.First().Vertices[0]);
//edge transfer should have left a gap in the edge list for current and new face, so create new edges to fill gap
CreateJoiningEdge(); //create edge from end to start (sets up face->edge and edge->face)
new_face.CreateJoiningEdge(); //other create edge from end to start (sets up face->edge and edge->face)
return(new_face);
}
public Shape Copy()
{
//create a new shape and copy the vertices
Shape shape = new Shape();
foreach (Vertex v in Vertices)
{
Vertex copy = shape.CreateVertex();
copy.Pos = v.Pos;
}
//put new vertices in a quick look up table
Vertex[] newverts = shape.Vertices.ToArray();
//go over each convex
foreach (Mesh c in Convexes)
{
//create a new convex in the new shape
Mesh convexcopy = shape.CreateConvex();
//copy edges
foreach (Edge e in c.Edges)
{
//create the edge and use look up table to build new vertex list
Edge edgecopy = convexcopy.CreateEdge();
edgecopy.Vertices = e.Vertices.Select(a => newverts[a.Idx]).ToArray();
//add this edge to each of the vertices it uses
foreach (Vertex v in edgecopy.Vertices)
{
v.OwnerEdges.Add(edgecopy);
}
}
//build look up table for the edges
Edge[] newedges = convexcopy.Edges.ToArray();
//copy faces
foreach (Face f in c.Faces)
{
//create the face and use look up tables to build new vertex/edge list
Face facecopy = convexcopy.CreateFace();
facecopy.Vertices = f.Vertices.Select(a => newverts[a.Idx]).ToList();
facecopy.Edges = f.Edges.Select(a => newedges[a.Idx]).ToList();
//add this face to each of the vertices it uses
foreach (Vertex v in facecopy.Vertices)
{
v.OwnerFaces.Add(facecopy);
}
//add this face to each of the edges it uses
foreach (Edge e in facecopy.Edges)
{
e.OwnerFaces.Add(facecopy);
}
}
}
return(shape);
}
