public void RemoveFromMeshEdgeLinksOfVertex(IVertex vertexToRemoveFrom)
{
// lets first fix up the MeshEdge pointed to by the vertexToRemoveFrom
if (vertexToRemoveFrom.FirstMeshEdge == this)
{
MeshEdge nextMeshEdgeConnectedToThisVertex = vertexToRemoveFrom.FirstMeshEdge.GetNextMeshEdgeConnectedTo(vertexToRemoveFrom);
// if this is a radial loop
if (nextMeshEdgeConnectedToThisVertex == vertexToRemoveFrom.FirstMeshEdge)
{
// the vertex is connected to no edges
vertexToRemoveFrom.FirstMeshEdge = null;
return;
}
else
{
// hook it up to the next connected mesh edge
vertexToRemoveFrom.FirstMeshEdge = nextMeshEdgeConnectedToThisVertex;
}
}
// now lets clean up the edge links on the mesh edges that are still connected to the vertexToRemoveFrom
MeshEdge nextEdgeThisConnectedTo = GetNextMeshEdgeConnectedTo(vertexToRemoveFrom);
if (nextEdgeThisConnectedTo == this)
{
throw new Exception("You can't disconnect when you are the only mesh edge.");
}
MeshEdge edgeAfterEdgeWeAreConnectedTo = nextEdgeThisConnectedTo.GetNextMeshEdgeConnectedTo(vertexToRemoveFrom);
if (edgeAfterEdgeWeAreConnectedTo == this)
{
// if only 2 edges (this and other) then set the other one to a circular reference to itself
int indexOnEdgeWeAreConnectedTo = nextEdgeThisConnectedTo.GetVertexEndIndex(vertexToRemoveFrom);
nextEdgeThisConnectedTo.NextMeshEdgeFromEnd[indexOnEdgeWeAreConnectedTo] = nextEdgeThisConnectedTo;
}
else
{
// we need to find the edge that has a reference to this one
MeshEdge edgeConnectedToThis = edgeAfterEdgeWeAreConnectedTo;
while (edgeConnectedToThis.GetNextMeshEdgeConnectedTo(vertexToRemoveFrom) != this)
{
edgeConnectedToThis = edgeConnectedToThis.GetNextMeshEdgeConnectedTo(vertexToRemoveFrom);
}
int indexOfThisOnOther = edgeConnectedToThis.GetVertexEndIndex(vertexToRemoveFrom);
edgeConnectedToThis.NextMeshEdgeFromEnd[indexOfThisOnOther] = nextEdgeThisConnectedTo;
}
// and set this one to null (it has no vertices)
VertexOnEnd[GetVertexEndIndex(vertexToRemoveFrom)] = null;
}
public IEnumerable <MeshEdge> ConnectedMeshEdges()
{
if (this.firstMeshEdge != null)
{
MeshEdge curMeshEdge = this.firstMeshEdge;
do
{
yield return(curMeshEdge);
curMeshEdge = curMeshEdge.GetNextMeshEdgeConnectedTo(this);
} while (curMeshEdge != this.firstMeshEdge);
}
}
/// <summary>
/// Unsplit (merge) the edgeToJoin and the edge that it is connected to through vertexToDelete.
/// Only unsplit the edge if we are reversing what would have been a split (a single vertex connecting only two edges).
/// </summary>
/// <param name="edgeToJoin"></param>
/// <param name="vertexToDelete"></param>
/// <returns></returns>
public void UnsplitMeshEdge(MeshEdge edgeToJoin, Vertex vertexToDelete)
{
int endToJoinIndex = edgeToJoin.GetVertexEndIndex(vertexToDelete);
MeshEdge edgeToDelete = edgeToJoin.GetNextMeshEdgeConnectedTo(vertexToDelete);
if (edgeToDelete.GetNextMeshEdgeConnectedTo(vertexToDelete) != edgeToJoin)
{
// make sure the edgeToJoin is a valid unsplit (only one connection)
throw new Exception("The edge that is being unsplit must be connected to only one other MeshEdge across the vertexToDelete.");
}
int otherEndOfEdgeToDelete = edgeToDelete.GetOpositeVertexEndIndex(vertexToDelete);
MeshEdge edgeToJoinTo = edgeToDelete.NextMeshEdgeFromEnd[otherEndOfEdgeToDelete];
// if the MeshEdge is part of any faces than we have to fix the faces.
if (edgeToJoin.firstFaceEdge != null)
{
// The edge we split was part of one or more faces, we need to fix the FaceEdge loops
foreach (FaceEdge faceEdge in edgeToJoin.FaceEdgesSharingMeshEdge())
{
FaceEdge faceEdgeToDelete = null;
if (faceEdge.nextFaceEdge.meshEdge == edgeToDelete)
{
faceEdgeToDelete = faceEdge.nextFaceEdge;
FaceEdge newNextFaceEdge = faceEdgeToDelete.nextFaceEdge;
newNextFaceEdge.prevFaceEdge = faceEdge;
faceEdge.nextFaceEdge = newNextFaceEdge;
}
else if (faceEdge.prevFaceEdge.meshEdge == edgeToDelete)
{
faceEdgeToDelete = faceEdge.prevFaceEdge;
FaceEdge newPrevFaceEdge = faceEdgeToDelete.prevFaceEdge;
newPrevFaceEdge.nextFaceEdge = faceEdge;
faceEdge.prevFaceEdge = newPrevFaceEdge;
}
else
{
throw new Exception("Either the next or prev edge must be the same as the edge to delete.");
}
// if the FaceEdge we are deleting is the one that the face was using as its firstFaceEdge, change it.
if (faceEdge.containingFace.firstFaceEdge == faceEdgeToDelete)
{
faceEdge.containingFace.firstFaceEdge = faceEdge;
}
// and clear out the FaceEdge we are deleting to help debugging and other references to it.
faceEdgeToDelete.nextFaceEdge = null;
faceEdgeToDelete.prevFaceEdge = null;
faceEdgeToDelete.radialNextFaceEdge = null;
faceEdgeToDelete.radialPrevFaceEdge = null;
faceEdgeToDelete.meshEdge = null;
faceEdgeToDelete.containingFace = null;
faceEdgeToDelete.firstVertex = null;
}
}
// fix the MeshEdgeLinks on the edgeToJoin
{
edgeToJoin.VertexOnEnd[endToJoinIndex] = edgeToDelete.VertexOnEnd[otherEndOfEdgeToDelete];
edgeToJoin.NextMeshEdgeFromEnd[endToJoinIndex] = edgeToDelete.NextMeshEdgeFromEnd[otherEndOfEdgeToDelete];
}
// Clear all the data on the deleted vertex and edge so we have less code that will work if it continues to use them.
vertexToDelete.firstMeshEdge = null;
edgeToDelete.firstFaceEdge = null;
edgeToDelete.VertexOnEnd[0] = null;
edgeToDelete.NextMeshEdgeFromEnd[0] = null;
edgeToDelete.VertexOnEnd[1] = null;
edgeToDelete.NextMeshEdgeFromEnd[1] = null;
}
/// <summary>
/// Unsplit (merge) the edgeToJoin and the edge that it is connected to through vertexToDelete.
/// Only unsplit the edge if we are reversing what would have been a split (a single vertex connecting only two edges).
/// </summary>
/// <param name="edgeToJoin"></param>
/// <param name="vertexToDelete"></param>
/// <returns></returns>
public void UnsplitMeshEdge(MeshEdge edgeToJoin, Vertex vertexToDelete)
{
int endToJoinIndex = edgeToJoin.GetVertexEndIndex(vertexToDelete);
MeshEdge edgeToDelete = edgeToJoin.GetNextMeshEdgeConnectedTo(vertexToDelete);
if (edgeToDelete.GetNextMeshEdgeConnectedTo(vertexToDelete) != edgeToJoin)
{
// make sure the edgeToJoin is a valid unsplit (only one connection)
throw new Exception("The edge that is being unsplit must be connected to only one other MeshEdge across the vertexToDelete.");
}
int otherEndOfEdgeToDelete = edgeToDelete.GetOpositeVertexEndIndex(vertexToDelete);
MeshEdge edgeToJoinTo = edgeToDelete.NextMeshEdgeFromEnd[otherEndOfEdgeToDelete];
// if the MeshEdge is part of any faces than we have to fix the faces.
if (edgeToJoin.firstFaceEdge != null)
{
// The edge we split was part of one or more faces, we need to fix the FaceEdge loops
foreach (FaceEdge faceEdge in edgeToJoin.FaceEdgesSharingMeshEdge())
{
FaceEdge faceEdgeToDelete = null;
if (faceEdge.nextFaceEdge.meshEdge == edgeToDelete)
{
faceEdgeToDelete = faceEdge.nextFaceEdge;
FaceEdge newNextFaceEdge = faceEdgeToDelete.nextFaceEdge;
newNextFaceEdge.prevFaceEdge = faceEdge;
faceEdge.nextFaceEdge = newNextFaceEdge;
}
else if (faceEdge.prevFaceEdge.meshEdge == edgeToDelete)
{
faceEdgeToDelete = faceEdge.prevFaceEdge;
FaceEdge newPrevFaceEdge = faceEdgeToDelete.prevFaceEdge;
newPrevFaceEdge.nextFaceEdge = faceEdge;
faceEdge.prevFaceEdge = newPrevFaceEdge;
}
else
{
throw new Exception("Either the next or prev edge must be the same as the edge to delete.");
}
// if the FaceEdge we are deleting is the one that the face was using as its firstFaceEdge, change it.
if (faceEdge.containingFace.firstFaceEdge == faceEdgeToDelete)
{
faceEdge.containingFace.firstFaceEdge = faceEdge;
}
// and clear out the FaceEdge we are deleting to help debugging and other references to it.
faceEdgeToDelete.nextFaceEdge = null;
faceEdgeToDelete.prevFaceEdge = null;
faceEdgeToDelete.radialNextFaceEdge = null;
faceEdgeToDelete.radialPrevFaceEdge = null;
faceEdgeToDelete.meshEdge = null;
faceEdgeToDelete.containingFace = null;
faceEdgeToDelete.firstVertex = null;
}
}
// fix the MeshEdgeLinks on the edgeToJoin
{
edgeToJoin.VertexOnEnd[endToJoinIndex] = edgeToDelete.VertexOnEnd[otherEndOfEdgeToDelete];
edgeToJoin.NextMeshEdgeFromEnd[endToJoinIndex] = edgeToDelete.NextMeshEdgeFromEnd[otherEndOfEdgeToDelete];
}
// Clear all the data on the deleted vertex and edge so we have less code that will work if it continues to use them.
vertexToDelete.firstMeshEdge = null;
edgeToDelete.firstFaceEdge = null;
edgeToDelete.VertexOnEnd[0] = null;
edgeToDelete.NextMeshEdgeFromEnd[0] = null;
edgeToDelete.VertexOnEnd[1] = null;
edgeToDelete.NextMeshEdgeFromEnd[1] = null;
}