private List <DisplacedVertex> FindDisplacedVertices(int maxWedges)
{
List <DisplacedVertex> displacedVertices = new List <DisplacedVertex>();
for (int i = m_initialWedges.Count - 1; i != maxWedges - 1; i--)
{
if (displacedVertices.Count == 0) //slight optim when list empty, no need to check if item already exists
{
displacedVertices.AddRange(m_initialWedges[i].m_displacedVertices);
}
else
{
for (int p = 0; p != m_initialWedges[i].m_displacedVertices.Count; p++)
{
DisplacedVertex vertex = m_initialWedges[i].m_displacedVertices[p];
//test if the vertex is already in the global list of displaced vertices
bool bVertexAlreadyExists = false;
for (int q = 0; q != displacedVertices.Count; q++)
{
if (displacedVertices[q].m_index == vertex.m_index)
{
bVertexAlreadyExists = true;
displacedVertices[q] = vertex; //update the vertex position
break;
}
}
if (!bVertexAlreadyExists)
{
displacedVertices.Add(vertex);
}
}
}
}
return(displacedVertices);
}
/**
* Collapse the wedge u onto the wedge v
* **/
private void Collapse(Wedge u, Wedge v)
{
// Collapse the edge uv by moving vertex u onto v
// Actually remove tris on uv, then update tris that
// have u to have v, and then remove u.
if (v == null)
{
// u is a vertex all by itself so just delete it
u.Delete();
m_wedges.Remove(u);
return;
}
//Find vertices that will collapse or be displaced
for (int i = 0; i != u.Vertices.Count; i++)
{
Vertex vertex = u.Vertices[i];
Vertex collapseVertex = vertex.FindVertexToCollapseOn(v); //the vertex it will collapse on if it exists
if (collapseVertex != null)
{
u.m_collapsedVertices.Add(vertex.ID, collapseVertex.ID); //no exception will be thrown as unique IDs are inserted into that dictionary
//CollapsedVertex collapsedVertex = new CollapsedVertex(vertex.ID, collapseVertex.ID);
//u.m_collapsedVertices.Add(collapsedVertex);
}
else
{
DisplacedVertex displacedVertex = new DisplacedVertex();
displacedVertex.m_index = vertex.ID;
displacedVertex.m_targetPosition = v.m_position;
u.m_displacedVertices.Add(displacedVertex);
}
}
//delete triangles on edge[u - v]
List <Triangle> sharedTriangles = u.GetSharedTrianglesWithWedge(v);
for (int i = 0; i != sharedTriangles.Count; i++)
{
//delete the triangle
sharedTriangles[i].Delete();
for (int j = 0; j != sharedTriangles[i].Vertices.Length; j++)
{
Vertex vertex = sharedTriangles[i].Vertices[j];
if (!u.HasVertex(vertex) && !v.HasVertex(vertex)) //the third wedge that is not u or v holds this vertex
{
if (vertex.AdjacentTriangles.Count == 0) //vertex is isolated, remove it
{
//find the wedge and remove the vertex from its internal list
GetWedgeHoldingVertex(m_wedges, vertex).RemoveVertex(vertex);
//add the vertex ID to the list of vertices deleted during the operation of collapsing u onto v
u.m_deletedVertices.Add(vertex.ID);
}
}
}
}
//perform the actual collapse
u.CollapseOnWedge(v);
//add u neighbors to v and add v as a new neighbor of u neighbors
for (int i = 0; i != u.Neighbors.Count; i++)
{
if (u.Neighbors[i] != v)
{
v.AddNeighbor(u.Neighbors[i]);
u.Neighbors[i].AddNeighbor(v);
}
}
//neighbors of wedge u are likely to have lost one triangle through one of their vertex so invalidate them
for (int i = 0; i != u.Neighbors.Count; i++)
{
u.Neighbors[i].InvalidateAdjacentTriangles();
}
//delete the wedge and remove it from global list
u.Delete();
m_wedges.Remove(u);
// recompute the edge collapse costs for neighboring wedges
for (int i = 0; i < u.Neighbors.Count; i++)
{
ComputeEdgeCostAtWedge(u.Neighbors[i]);
}
}
