private bool ShouldRemoveEdge(HEEdge edge, bool pairInOtherSide)
{
HEEdge pair = heEdges[edge.pair];
return !pairInOtherSide || (pairInOtherSide && (pair.startVertex != edge.endVertex || pair.endVertex != edge.startVertex));
}
/**
* Analyzes the input mesh and populates the half-edge structure. Can be called as many times you want (for examples if the original mesh is modified).
*/
public IEnumerator Generate()
{
if (input != null){
heFaces.Clear();
heVertices.Clear();
heEdges.Clear();
_area = 0;
_modified = false;
Dictionary<Vector3, HEVertex> vertexBuffer = new Dictionary<Vector3, HEVertex>();
Dictionary<KeyValuePair<int,int>,HEEdge> edgeBuffer = new Dictionary<KeyValuePair<int,int>,HEEdge>();
// Get copies of vertex and triangle buffers:
Vector3[] vertices = input.vertices;
int[] triangles = input.triangles;
// first, create vertices:
for(int i = 0; i < vertices.Length; i++){
//if the vertex already exists, add physical vertex index to it.
HEVertex vertex;
if (vertexBuffer.TryGetValue(vertices[i], out vertex)){
vertex.physicalIDs.Add(i);
}else{
vertex = new HEVertex(i);
}
vertexBuffer[vertices[i]] = vertex;
if (i % 200 == 0)
yield return new CoroutineJob.ProgressInfo("Half-edge: analyzing vertices...",i/(float)vertices.Length);
}
// assign unique indices to vertices:
int index = 0;
foreach(KeyValuePair<Vector3,HEVertex> pair in vertexBuffer){
((HEVertex)pair.Value).index = index;
heVertices.Add(pair.Value);
if (index % 200 == 0)
yield return new CoroutineJob.ProgressInfo("Half-edge: assigning indices...",index/(float)vertices.Length);
index++;
}
// build half edge structure:
for(int i = 0; i<triangles.Length;i+=3){
Vector3 pos1 = vertices[triangles[i]];
Vector3 pos2 = vertices[triangles[i+1]];
Vector3 pos3 = vertices[triangles[i+2]];
HEVertex v1 = vertexBuffer[pos1];
HEVertex v2 = vertexBuffer[pos2];
HEVertex v3 = vertexBuffer[pos3];
// create half edges:
HEEdge e1 = new HEEdge();
e1.index = heEdges.Count;
e1.indexOnFace = 0;
e1.faceIndex = heFaces.Count;
e1.endVertex = v1.index;
e1.startVertex = v2.index;
HEEdge e2 = new HEEdge();
e2.index = heEdges.Count+1;
e2.indexOnFace = 1;
e2.faceIndex = heFaces.Count;
e2.endVertex = v2.index;
e2.startVertex = v3.index;
HEEdge e3 = new HEEdge();
e3.index = heEdges.Count+2;
e3.indexOnFace = 2;
e3.faceIndex = heFaces.Count;
e3.endVertex = v3.index;
e3.startVertex = v1.index;
// link half edges together:
e1.nextEdgeIndex = e3.index;
e2.nextEdgeIndex = e1.index;
e3.nextEdgeIndex = e2.index;
// vertex outgoing half edge indices:
v1.halfEdgeIndex = e3.index;
v2.halfEdgeIndex = e1.index;
v3.halfEdgeIndex = e2.index;
// add edges:
heEdges.Add(e1);
heEdges.Add(e2);
heEdges.Add(e3);
// populate and add face:
HEFace face = new HEFace();
face.edges[0] = e1.index;
face.edges[1] = e2.index;
face.edges[2] = e3.index;
face.area = ObiUtils.TriangleArea(pos1,pos2,pos3);
_area += face.area;
_volume += Vector3.Dot(Vector3.Cross(pos1,pos2),pos3)/6f;
face.index = heFaces.Count;
heFaces.Add(face);
try{
edgeBuffer.Add(new KeyValuePair<int,int>(v1.index,v2.index),e1);
edgeBuffer.Add(new KeyValuePair<int,int>(v2.index,v3.index),e2);
edgeBuffer.Add(new KeyValuePair<int,int>(v3.index,v1.index),e3);
}catch{
Debug.LogError("Your mesh is non manifold, and thus cannot be processed by Obi: more than 1 edge joining the same pair of vertices.");
heFaces.Clear();
heVertices.Clear();
heEdges.Clear();
_area = 0;
yield break;
}
if (i % 500 == 0)
yield return new CoroutineJob.ProgressInfo("Half-edge: generating edges and faces...",i/(float)triangles.Length);
}
List<HEEdge> borderEdges = new List<HEEdge>(); //edges belonging to a mesh border.
// stitch half edge pairs together:
index = 0;
foreach(KeyValuePair<KeyValuePair<int,int>,HEEdge> pair in edgeBuffer){
KeyValuePair<int,int> edgeKey = new KeyValuePair<int,int>(pair.Key.Value,pair.Key.Key);
HEEdge edge = null;
if (edgeBuffer.TryGetValue(edgeKey, out edge)){
((HEEdge)pair.Value).pair = edge.index;
}else{
//create border edge:
HEEdge e = new HEEdge();
e.index = heEdges.Count;
e.endVertex = ((HEEdge)pair.Value).startVertex;
e.startVertex = ((HEEdge)pair.Value).endVertex;
heVertices[e.startVertex].halfEdgeIndex = e.index;
e.pair = ((HEEdge)pair.Value).index;
((HEEdge)pair.Value).pair = e.index;
heEdges.Add(e);
borderEdges.Add(e);
}
if (index % 1000 == 0)
yield return new CoroutineJob.ProgressInfo("Half-edge: stitching half-edges...",index/(float)edgeBuffer.Count);
index++;
}
_closed = borderEdges.Count == 0;
// link together border edges:
foreach(HEEdge edge in borderEdges){
edge.nextEdgeIndex = heVertices[edge.endVertex].halfEdgeIndex;
}
}else{
Debug.LogWarning("Tried to generate adjacency info for an empty mesh.");
}
}
