public void StartVisualizer(HalfEdgeData3 halfEdgeMeshData, int maxEdgesToContract, float maxError, bool normalizeTriangles = false)
{
controller = GetComponent <VisualizerController3D>();
//
// Compute the Q matrices for all the initial vertices
//
//Put the result in a lookup dictionary
//This assumes we have no floating point precision issues, so vertices at the same position have to be at the same position
Dictionary <MyVector3, Matrix4x4> qMatrices = new Dictionary <MyVector3, Matrix4x4>();
HashSet <HalfEdgeVertex3> vertices = halfEdgeMeshData.verts;
//timer.Start();
//0.142 seconds for the bunny (0.012 for dictionary lookup, 0.024 to calculate the Q matrices, 0.087 to find edges going to vertex)
foreach (HalfEdgeVertex3 v in vertices)
{
//Have we already calculated a Q matrix for this vertex?
//Remember that we have multiple vertices at the same position in the half-edge data structure
//timer.Start();
if (qMatrices.ContainsKey(v.position))
{
continue;
}
//timer.Stop();
//Calculate the Q matrix for this vertex
//timer.Start();
//Find all edges meeting at this vertex
HashSet <HalfEdge3> edgesPointingToThisVertex = v.GetEdgesPointingToVertex(halfEdgeMeshData);
//timer.Stop();
//timer.Start();
Matrix4x4 Q = MeshSimplification_QEM.CalculateQMatrix(edgesPointingToThisVertex, normalizeTriangles);
//timer.Stop();
qMatrices.Add(v.position, Q);
}
//timer.Stop();
//
// Select all valid pairs that can be contracted
//
List <HalfEdge3> validPairs = new List <HalfEdge3>(halfEdgeMeshData.edges);
//
// Compute the cost of contraction for each pair
//
HashSet <QEM_Edge> QEM_edges = new HashSet <QEM_Edge>();
//We need a lookup table to faster remove and update QEM_edges
Dictionary <HalfEdge3, QEM_Edge> halfEdge_QEM_Lookup = new Dictionary <HalfEdge3, QEM_Edge>();
foreach (HalfEdge3 halfEdge in validPairs)
{
MyVector3 p1 = halfEdge.prevEdge.v.position;
MyVector3 p2 = halfEdge.v.position;
Matrix4x4 Q1 = qMatrices[p1];
Matrix4x4 Q2 = qMatrices[p2];
QEM_Edge QEM_edge = new QEM_Edge(halfEdge, Q1, Q2);
QEM_edges.Add(QEM_edge);
halfEdge_QEM_Lookup.Add(halfEdge, QEM_edge);
}
//
// Sort all pairs, with the minimum cost pair at the top
//
//The fastest way to keep the data sorted is to use a heap
Heap <QEM_Edge> sorted_QEM_edges = new Heap <QEM_Edge>(QEM_edges.Count);
foreach (QEM_Edge e in QEM_edges)
{
sorted_QEM_edges.Add(e);
}
//Main visualization algorithm coroutine
StartCoroutine(QEMLoop(halfEdgeMeshData, sorted_QEM_edges, qMatrices, halfEdge_QEM_Lookup, maxEdgesToContract, maxError, normalizeTriangles));
}
private IEnumerator QEMLoop(HalfEdgeData3 halfEdgeMeshData, Heap <QEM_Edge> sorted_QEM_edges, Dictionary <MyVector3, Matrix4x4> qMatrices, Dictionary <HalfEdge3, QEM_Edge> halfEdge_QEM_Lookup, int maxEdgesToContract, float maxError, bool normalizeTriangles = false)
{
//PAUSE FOR VISUALIZATION
//Display what we have so far
controller.DisplayMeshMain(halfEdgeMeshData.faces);
controller.displayStuffUI.text = "Triangles: " + halfEdgeMeshData.faces.Count.ToString();
yield return(new WaitForSeconds(5f));
//
// Start contracting edges
//
//For each edge we want to remove
for (int i = 0; i < maxEdgesToContract; i++)
{
//Check that we can simplify the mesh
//The smallest mesh we can have is a tetrahedron with 4 faces, itherwise we get a flat triangle
if (halfEdgeMeshData.faces.Count <= 4)
{
Debug.Log($"Cant contract more than {i} edges");
break;
}
//
// Remove the pair (v1,v2) of the least cost and contract the pair
//
//timer.Start();
QEM_Edge smallestErrorEdge = sorted_QEM_edges.RemoveFirst();
//This means an edge in this face has already been contracted
//We are never removing edges from the heap after contracting and edges,
//so we do it this way for now, which is maybe better?
if (smallestErrorEdge.halfEdge.face == null)
{
//This edge wasn't contracted so don't add it to iteration
i -= 1;
continue;
}
if (smallestErrorEdge.qem > maxError)
{
Debug.Log($"Cant contract more than {i} edges because reached max error");
break;
}
//timer.Stop();
//timer.Start();
//Get the half-edge we want to contract
HalfEdge3 edgeToContract = smallestErrorEdge.halfEdge;
//Need to save the endpoints so we can remove the old Q matrices from the pos-matrix lookup table
Edge3 contractedEdgeEndpoints = new Edge3(edgeToContract.prevEdge.v.position, edgeToContract.v.position);
//Contract edge
HashSet <HalfEdge3> edgesPointingToNewVertex = halfEdgeMeshData.ContractTriangleHalfEdge(edgeToContract, smallestErrorEdge.mergePosition);
//timer.Stop();
//
// Remove all QEM_edges that belonged to the faces we contracted
//
//This is not needed if we check if an edge in the triangle has already been contracted
/*
* //timer.Start();
*
* //This edge doesnt exist anymore, so remove it from the lookup
* halfEdge_QEM_Lookup.Remove(edgeToContract);
*
* //Remove the two edges that were a part of the triangle of the edge we contracted
* RemoveHalfEdgeFromQEMEdges(edgeToContract.nextEdge, QEM_edges, halfEdge_QEM_Lookup);
* RemoveHalfEdgeFromQEMEdges(edgeToContract.nextEdge.nextEdge, QEM_edges, halfEdge_QEM_Lookup);
*
* //Remove the three edges belonging to the triangle on the opposite side of the edge we contracted
* //If there was an opposite side...
* if (edgeToContract.oppositeEdge != null)
* {
* HalfEdge3 oppositeEdge = edgeToContract.oppositeEdge;
*
* RemoveHalfEdgeFromQEMEdges(oppositeEdge, QEM_edges, halfEdge_QEM_Lookup);
* RemoveHalfEdgeFromQEMEdges(oppositeEdge.nextEdge, QEM_edges, halfEdge_QEM_Lookup);
* RemoveHalfEdgeFromQEMEdges(oppositeEdge.nextEdge.nextEdge, QEM_edges, halfEdge_QEM_Lookup);
* }
* //timer.Stop();
*/
//Remove the edges start and end vertices from the pos-matrix lookup table
qMatrices.Remove(contractedEdgeEndpoints.p1);
qMatrices.Remove(contractedEdgeEndpoints.p2);
//timer.Stop();
//
// Update all QEM_edges that is now connected with the new contracted vertex because their errors have changed
//
//The contracted position has a new Q matrix
Matrix4x4 QNew = MeshSimplification_QEM.CalculateQMatrix(edgesPointingToNewVertex, normalizeTriangles);
//Add the Q matrix to the pos-matrix lookup table
qMatrices.Add(smallestErrorEdge.mergePosition, QNew);
//Update the error of the QEM_edges of the edges that pointed to and from one of the two old Q matrices
//Those edges are the same edges that points to the new vertex and goes from the new vertex
//timer.Start();
foreach (HalfEdge3 edgeToV in edgesPointingToNewVertex)
{
//The edge going from the new vertex is the next edge of the edge going to the vertex
HalfEdge3 edgeFromV = edgeToV.nextEdge;
//To
QEM_Edge QEM_edgeToV = halfEdge_QEM_Lookup[edgeToV];
Edge3 edgeToV_endPoints = QEM_edgeToV.GetEdgeEndPoints();
Matrix4x4 Q1_edgeToV = qMatrices[edgeToV_endPoints.p1];
Matrix4x4 Q2_edgeToV = QNew;
QEM_edgeToV.UpdateEdge(edgeToV, Q1_edgeToV, Q2_edgeToV);
sorted_QEM_edges.UpdateItem(QEM_edgeToV);
//From
QEM_Edge QEM_edgeFromV = halfEdge_QEM_Lookup[edgeFromV];
Edge3 edgeFromV_endPoints = QEM_edgeFromV.GetEdgeEndPoints();
Matrix4x4 Q1_edgeFromV = QNew;
Matrix4x4 Q2_edgeFromV = qMatrices[edgeFromV_endPoints.p2];
QEM_edgeFromV.UpdateEdge(edgeFromV, Q1_edgeFromV, Q2_edgeFromV);
sorted_QEM_edges.UpdateItem(QEM_edgeFromV);
}
//timer.Stop();
//PAUSE FOR VISUALIZATION
//Display what we have so far
controller.DisplayMeshMain(halfEdgeMeshData.faces);
controller.displayStuffUI.text = "Triangles: " + halfEdgeMeshData.faces.Count.ToString();
yield return(new WaitForSeconds(0.02f));
}
}
