protected override HalfEdgeMesh.Vertex Merge(MergeArgs args)
{
return(TriMeshModify.MergeEdge(args.Target, args.Pos));
}
public bool RemoveVertex4(TriMesh.Vertex cur)
{
/* cur
* vl vr /\
* |\ /| / \
* | \ / | / \
* | \ / | / \
* | cur | / \
* | / \ | / \
* | / \ | lm-----sm-----rm
* |/face \| / \ /\ / \
* left-----right / \ / \ / \
* \ / / sl____sr \
* \ / / \ / \
* \ / / \ / \
* vm / \/ \
* left----------mm----------right
*
* 中部三角形放大图
*/
TriMesh.HalfEdge curToLeft = null;
//找到一个可用的面，这个面的3个邻面必须都存在
foreach (var item in cur.HalfEdges)
{
if (item.Face != null && item.Face.FaceCount == 3)
{
curToLeft = item;
break;
}
}
if (curToLeft == null)
{
return(false);
}
TriMesh.Vertex left, right, vl, vr, vm,
lm, sm, rm, sl, sr, mm;
TriMesh.HalfEdge leftToRight = curToLeft.Next;
TriMesh.HalfEdge rightToCur = leftToRight.Next;
left = curToLeft.ToVertex;
right = leftToRight.ToVertex;
vl = curToLeft.Opposite.Next.ToVertex;
vr = rightToCur.Opposite.Next.ToVertex;
vm = leftToRight.Opposite.Next.ToVertex;
lm = this.AddMid(left, cur);
rm = this.AddMid(right, cur);
mm = this.AddMid(left, right);
sm = this.AddMid(lm, rm);
sl = this.AddMid(lm, mm);
sr = this.AddMid(mm, rm);
TriMeshModify.RemoveEdge(curToLeft.Edge);
TriMeshModify.RemoveEdge(leftToRight.Edge);
TriMeshModify.RemoveEdge(rightToCur.Edge);
//图1外圈三角形
this.CreateFace(vl, left, lm);
this.CreateFace(vl, lm, cur);
this.CreateFace(vr, cur, rm);
this.CreateFace(vr, rm, right);
this.CreateFace(mm, left, vm);
this.CreateFace(mm, vm, right);
//图2外圈三角形
this.CreateFace(cur, lm, sm);
this.CreateFace(cur, sm, rm);
this.CreateFace(lm, left, sl);
this.CreateFace(sl, left, mm);
this.CreateFace(rm, sr, right);
this.CreateFace(sr, mm, right);
//图2内圈三角形
this.CreateFace(sm, lm, sl);
this.CreateFace(sm, sr, rm);
this.CreateFace(sm, sl, sr);
this.CreateFace(sl, mm, sr);
return(true);
}
public TriMesh Cut(IEnumerable <TriMesh.Vertex> region)
{
Dictionary <int, TriMesh.Vertex> vMap = new Dictionary <int, HalfEdgeMesh.Vertex>();
Dictionary <int, bool> fFlag = new Dictionary <int, bool>();
TriMesh newMesh = new TriMesh();
foreach (var v in region)
{
TriMesh.Vertex newV = new HalfEdgeMesh.Vertex(
new VertexTraits(v.Traits.Position));
vMap[v.Index] = newV;
newMesh.AppendToVertexList(newV);
}
foreach (var f in this.mesh.Faces)
{
bool inner = true;
foreach (var v in f.Vertices)
{
if (!vMap.ContainsKey(v.Index))
{
inner = false;
break;
}
}
if (inner)
{
TriMesh.HalfEdge hf = f.HalfEdge;
newMesh.Faces.AddTriangles(
vMap[hf.FromVertex.Index],
vMap[hf.ToVertex.Index],
vMap[hf.Next.ToVertex.Index]);
fFlag[f.Index] = true;
}
}
List <TriMesh.Edge> remove = new List <HalfEdgeMesh.Edge>();
foreach (var e in this.mesh.Edges)
{
if (fFlag.ContainsKey(e.Face0.Index) &&
fFlag.ContainsKey(e.Face1.Index))
{
remove.Add(e);
}
}
foreach (var e in remove)
{
TriMeshModify.RemoveEdge(e);
}
foreach (var v in region)
{
bool inner = true;
foreach (var round in v.Vertices)
{
if (!vMap.ContainsKey(round.Index))
{
inner = false;
}
}
if (inner)
{
this.mesh.RemoveVertex(v);
}
}
return(newMesh);
}
