public static TriMesh.HalfEdge Split(TriMesh.HalfEdge hf, Vector3D v1Pos, Vector3D v2Pos)
{
TriMesh mesh = (TriMesh)hf.Mesh;
List <TriMesh.HalfEdge> list = new List <HalfEdgeMesh.HalfEdge>();
TriMesh.HalfEdge cur = hf;
list.Add(cur);
do
{
cur = cur.Opposite.Next;
list.Add(cur);
} while (cur.Opposite.Face != null && cur != hf);
for (int i = 1; i < list.Count; i++)
{
TriMeshModify.RemoveEdge(list[i].Edge);
}
hf.FromVertex.Traits.Position = v1Pos;
TriMesh.Vertex v2 = new HalfEdgeMesh.Vertex(new VertexTraits(v2Pos));
mesh.AppendToVertexList(v2);
for (int i = 1; i < list.Count; i++)
{
mesh.Faces.AddTriangles(list[i - 1].ToVertex, v2, list[i].ToVertex);
}
mesh.Faces.AddTriangles(list[0].ToVertex, hf.FromVertex, v2);
return(hf.FromVertex.FindHalfedgeTo(v2));
}
/// <summary>
/// 两端点都在边界上
/// </summary>
/// <param name="edge"></param>
void CutBothBoundary(TriMesh.Edge edge)
{
TriMesh.HalfEdge hf = edge.HalfEdge0;
TriMesh.HalfEdge[] leftArr = this.GetToBoundaryAntiClockWise(hf);
TriMesh.HalfEdge[] rightArr = this.GetToBoundaryClockWise(hf.Next);
for (int i = 1; i < leftArr.Length; i++)
{
TriMeshModify.RemoveEdge(leftArr[i].Edge);
}
for (int i = 0; i < rightArr.Length; i++)
{
TriMeshModify.RemoveEdge(rightArr[i].Edge);
}
Vector3D vec = this.GetMoveVector(hf.Opposite);
TriMesh.Vertex left = this.Clone(hf.FromVertex, vec);
TriMesh.Vertex right = this.Clone(hf.ToVertex, vec);
for (int i = 2; i < leftArr.Length; i++)
{
this.mesh.Faces.AddTriangles(left, leftArr[i - 1].ToVertex, leftArr[i].ToVertex);
}
for (int i = 1; i < rightArr.Length; i++)
{
this.mesh.Faces.AddTriangles(right, rightArr[i].ToVertex, rightArr[i - 1].ToVertex);
}
this.mesh.Faces.AddTriangles(left, right, leftArr[1].ToVertex);
}
public void Remove(IEnumerable <TriMesh.Face> region)
{
foreach (var f in region)
{
TriMeshModify.RemoveFace(f);
}
foreach (var e in removeEdge)
{
TriMeshModify.RemoveEdge(e);
}
foreach (var v in removeVertex)
{
TriMeshModify.RemoveVertex(v);
}
}
bool RemoveVertex3(TriMesh.Vertex top)
{
/*
* top
* / \
* / \
* /face \
* left-----right
* \ /
* \ /
* \ /
* buttom
*/
TriMesh.HalfEdge leftToRight = null;
//找到一个可用的面，top顶点的对边不在边界上
foreach (var item in top.HalfEdges)
{
if (!item.Next.OnBoundary)
{
leftToRight = item.Next;
break;
}
}
if (leftToRight == null)
{
return(false);
}
TriMesh.Vertex left, buttom, right, mid;
left = leftToRight.FromVertex;
right = leftToRight.ToVertex;
mid = this.AddMid(left, right);
buttom = leftToRight.Opposite.Next.ToVertex;
TriMeshModify.RemoveEdge(leftToRight.Edge);
//连接中点，把2个三角形拆成4个
this.CreateFace(top, left, mid);
this.CreateFace(top, mid, right);
this.CreateFace(buttom, right, mid);
this.CreateFace(buttom, mid, left);
return(true);
}
void CutInner(TriMesh.HalfEdge cur, TriMesh.HalfEdge next)
{
TriMesh.Vertex share1 = cur.FromVertex;
TriMesh.Vertex share2 = next.ToVertex;
TriMesh.Vertex mid = cur.ToVertex;
Vector3D normal = TriMeshUtil.ComputeNormalFace(cur.Face);
Vector3D vec = next.ToVertex.Traits.Position - cur.FromVertex.Traits.Position;
Vector3D dir = normal.Cross(vec).Normalize();
TriMesh.Vertex v2 = TriMeshModify.VertexSplit(mid, share1, share2,
mid.Traits.Position - dir * move, mid.Traits.Position + dir * move);
TriMesh.HalfEdge hf = mid.FindHalfedgeTo(v2);
TriMeshModify.RemoveEdge(hf.Edge);
this.vertexMap.Add(mid, v2);
}
/// <summary>
/// 源点在边界上
/// </summary>
/// <param name="hf"></param>
void CutFromBoundary(TriMesh.HalfEdge hf)
{
TriMesh.HalfEdge[] arr = this.GetToBoundaryAntiClockWise(hf);
for (int i = 1; i < arr.Length; i++)
{
TriMeshModify.RemoveEdge(arr[i].Edge);
}
Vector3D vec = this.GetMoveVector(hf.Opposite);
TriMesh.Vertex v2 = this.Clone(hf.FromVertex, vec);
for (int i = 1; i < arr.Length; i++)
{
this.mesh.Faces.AddTriangles(v2, arr[i - 1].ToVertex, arr[i].ToVertex);
}
}
public void Cut(Plane plane)
{
this.plane = plane;
this.list = new List <Triangle>();
this.cutPoint = new Dictionary <int, CutPoint>();
foreach (var hf in this.mesh.HalfEdges)
{
this.CutHalfEdge(hf);
}
foreach (var face in this.mesh.Faces)
{
this.CutFace(face);
}
List <TriMesh.Edge> edges = new List <HalfEdgeMesh.Edge>();
foreach (var hf in this.mesh.HalfEdges)
{
if (this.cutPoint.ContainsKey(hf.Index))
{
edges.Add(hf.Edge);
}
}
foreach (var item in edges)
{
TriMeshModify.RemoveEdge(item);
}
foreach (var item in this.list)
{
this.mesh.Faces.AddTriangles(item.V1, item.V2, item.V3);
}
TriMeshUtil.FixIndex(mesh);
TriMeshUtil.SetUpNormalVertex(mesh);
}
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);
}
