IList <IndexSegment> setupEdges(IList <int> vertxIndices)
{
IList <IndexSegment> indexList = new List <IndexSegment>();
int boundLinesDictOffset = 0;
if (boundaryLinesDict == null)
{
IEqualityComparer <IndexSegment> segCompare = new SegmentComparer(false /*compareBothDirections*/);
boundaryLinesDict = new Dictionary <IndexSegment, int>(segCompare);
}
else
{
boundLinesDictOffset = boundaryLinesDict.Count();
}
for (int ii = 0; ii < vertxIndices.Count; ++ii)
{
IndexSegment segm;
if (ii == vertxIndices.Count - 1)
{
segm = new IndexSegment(vertxIndices[ii], vertxIndices[0]);
}
else
{
segm = new IndexSegment(vertxIndices[ii], vertxIndices[ii + 1]);
}
indexList.Add(segm);
boundaryLinesDict.Add(segm, ii + boundLinesDictOffset); // boundaryLinesDict is a dictionary for the combined outer and inner boundaries, the values should be sequential
}
return(indexList);
}
void SetupEdges(IList <int> vertxIndices, int idxOffset)
{
int boundLinesDictOffset = 0;
if (BoundaryLinesDict == null)
{
IEqualityComparer <IndexSegment> segCompare = new SegmentComparer(false /*compareBothDirections*/);
BoundaryLinesDict = new Dictionary <IndexSegment, int>(segCompare);
}
else
{
boundLinesDictOffset = BoundaryLinesDict.Count();
}
int prevIdx = 0;
int idx = 0;
int vertCount = vertxIndices.Count;
foreach (int vIdx in vertxIndices)
{
IndexSegment segm = null;
if (idx > 0)
{
segm = new IndexSegment(prevIdx, vIdx);
OuterAndInnerBoundaries.Add(idx - 1 + idxOffset, segm);
BoundaryLinesDict.Add(segm, (idx - 1 + boundLinesDictOffset)); // boundaryLinesDict is a dictionary for the combined outer and inner boundaries, the values should be sequential
}
if (idx == vertCount - 1) // The last index. Close the loop by connecing it to the first index
{
segm = new IndexSegment(vIdx, vertxIndices[0]);
OuterAndInnerBoundaries.Add((idx + idxOffset), segm);
BoundaryLinesDict.Add(segm, (idx + boundLinesDictOffset)); // boundaryLinesDict is a dictionary for the combined outer and inner boundaries, the values should be sequential
}
prevIdx = vIdx;
idx++;
}
}
/// <summary>
/// Go through the input face list that share the same vertex and has the same normal (coplannar).
/// </summary>
/// <param name="inputFaceList"></param>
/// <param name="outputFaceList"></param>
/// <returns>True if done successfully</returns>
void TryMergeFaces(List <int> inputFaceList, out List <int> outputFaceList)
{
outputFaceList = new List <int>();
IndexFace firstF = m_FacesCollDict[inputFaceList[0]];
int currProcFace = inputFaceList[0];
inputFaceList.RemoveAt(0); // remove the first face from the list
bool merged = false;
IEqualityComparer <IndexSegment> segCompare = new SegmentComparer(false /*compareBothDirections*/);
IDictionary <IndexSegment, Tuple <int, int> > segmentOfFaceDict = new Dictionary <IndexSegment, Tuple <int, int> >(segCompare);
IList <int> discardList = new List <int>();
foreach (int fidx in inputFaceList)
{
if (!SegmentOfFaceToDict(ref segmentOfFaceDict, fidx))
{
discardList.Add(fidx);
}
}
// Remove bad face from the input list, if any
if (discardList.Count > 0)
{
foreach (int fidx in discardList)
{
inputFaceList.Remove(fidx);
}
}
discardList.Clear();
while (inputFaceList.Count > 0)
{
IndexFace mergedFace = null;
for (int currEdgeIdx = 0; currEdgeIdx < firstF.OuterAndInnerBoundaries.Count; currEdgeIdx++)
{
IndexSegment currEdge = firstF.OuterAndInnerBoundaries[currEdgeIdx];
IndexSegment reversedEdge = currEdge.Reverse();
IndexFace currFace = null;
int currFaceIdx = -1;
int idx = -1;
Tuple <int, int> pairedFace = null;
if (!segmentOfFaceDict.TryGetValue(reversedEdge, out pairedFace))
{
if (!segmentOfFaceDict.TryGetValue(currEdge, out pairedFace))
{
merged = false;
continue;
}
else
{
currFaceIdx = pairedFace.Item1;
currFace = m_FacesCollDict[currFaceIdx];
// Need to reverse the face boundaries. Remove the entries in the Dict first, reverse the face, and add them back
for (int cidx = 0; cidx < currFace.OuterAndInnerBoundaries.Count; ++cidx)
{
segmentOfFaceDict.Remove(currFace.OuterAndInnerBoundaries[cidx]);
}
currFace.Reverse();
if (!SegmentOfFaceToDict(ref segmentOfFaceDict, currFaceIdx))
{
// Something is wrong with this face (should not be here in the normal circumstance), discard it and continue
inputFaceList.Remove(currFaceIdx);
merged = false;
continue;
}
if (!segmentOfFaceDict.TryGetValue(reversedEdge, out pairedFace))
{
if (!segmentOfFaceDict.TryGetValue(currEdge, out pairedFace))
{
// Should not be here. If somehow here, discard the face and continue
inputFaceList.Remove(currFaceIdx);
merged = false;
continue;
}
}
idx = pairedFace.Item2;
}
}
else
{
currFaceIdx = pairedFace.Item1;
currFace = m_FacesCollDict[currFaceIdx];
idx = pairedFace.Item2;
}
// Now we need to check other edges of this face whether there is other coincide edge (this is in the case of hole(s))
List <int> fFaceIdxList = new List <int>();
List <int> currFaceIdxList = new List <int>();
int ci = -1;
foreach (KeyValuePair <int, IndexSegment> idxSeg in currFace.OuterAndInnerBoundaries)
{
ci++;
if (ci == idx)
{
continue; // skip already known coincide edge
}
int ffIdx = -1;
IndexSegment reL = new IndexSegment(idxSeg.Value.EndPIndex, idxSeg.Value.StartPindex);
ffIdx = firstF.FindMatchedIndexSegment(reL);
if (ffIdx > 0)
{
fFaceIdxList.Add(ffIdx); // List of edges to skip when merging
currFaceIdxList.Add(ci); // List of edges to skip when merging
}
}
// Now we will remove the paired edges and merge the faces
List <IndexSegment> newFaceEdges = new List <IndexSegment>();
for (int ii = 0; ii < currEdgeIdx; ii++)
{
bool toSkip = false;
if (fFaceIdxList.Count > 0)
{
toSkip = fFaceIdxList.Contains(ii);
}
if (!toSkip)
{
newFaceEdges.Add(firstF.OuterAndInnerBoundaries[ii]); // add the previous edges from the firstF faces first. This will skip the currEdge
}
}
// Add the next-in-sequence edges from the second face
for (int ii = idx + 1; ii < currFace.OuterAndInnerBoundaries.Count; ii++)
{
bool toSkip = false;
if (currFaceIdxList.Count > 0)
{
toSkip = currFaceIdxList.Contains(ii);
}
if (!toSkip)
{
newFaceEdges.Add(currFace.OuterAndInnerBoundaries[ii]);
}
}
for (int ii = 0; ii < idx; ii++)
{
bool toSkip = false;
if (currFaceIdxList.Count > 0)
{
toSkip = currFaceIdxList.Contains(ii);
}
if (!toSkip)
{
newFaceEdges.Add(currFace.OuterAndInnerBoundaries[ii]);
}
}
for (int ii = currEdgeIdx + 1; ii < firstF.OuterAndInnerBoundaries.Count; ii++)
{
bool toSkip = false;
if (fFaceIdxList.Count > 0)
{
toSkip = fFaceIdxList.Contains(ii);
}
if (!toSkip)
{
newFaceEdges.Add(firstF.OuterAndInnerBoundaries[ii]);
}
}
// Build a new face
// Important to note that the list of edges may not be continuous if there is a hole. We need to go through the list here to identify whether there is any such
// discontinuity and collect the edges into their respective loops
List <List <IndexSegment> > loops = new List <List <IndexSegment> >();
List <IndexSegment> loopEdges = new List <IndexSegment>();
loops.Add(loopEdges);
IndexSegment prevSegm = newFaceEdges[0];
foreach (IndexSegment idxSeg in newFaceEdges)
{
if (prevSegm == idxSeg)
{
loopEdges.Add(idxSeg);
}
else
{
if (idxSeg.StartPindex == prevSegm.EndPIndex)
{
loopEdges.Add(idxSeg);
}
else
{
// Discontinuity detected
loopEdges = new List <IndexSegment>(); // start new loop
loops.Add(loopEdges);
loopEdges.Add(idxSeg);
}
}
prevSegm = idxSeg;
}
List <List <IndexSegment> > finalLoops = new List <List <IndexSegment> >();
{
while (loops.Count > 1)
{
// There are more than 1 loops, need to consolidate if there are fragments to combine due to their continuity between the fragments
int toDelIdx = -1;
for (int ii = 1; ii < loops.Count; ii++)
{
if (loops[0][loops[0].Count - 1].EndPIndex == loops[ii][0].StartPindex)
{
// found continuity, merge the loops
List <IndexSegment> newLoop = new List <IndexSegment>(loops[0]);
newLoop.AddRange(loops[ii]);
finalLoops.Add(newLoop);
toDelIdx = ii;
break;
}
}
if (toDelIdx > 0)
{
loops.RemoveAt(toDelIdx); // !!!! Important to remove the later member first before removing the first one
loops.RemoveAt(0);
}
else
{
// No continuity found, copy the first loop to the final loop
List <IndexSegment> newLoop = new List <IndexSegment>(loops[0]);
finalLoops.Add(newLoop);
loops.RemoveAt(0);
}
}
if (loops.Count > 0)
{
// Add remaining list into the final loops
finalLoops.AddRange(loops);
}
}
if (finalLoops.Count > 1)
{
// Find the largest loop and put it in the first position signifying the outer loop and the rest are the inner loops
int largestPerimeterIdx = 0;
double largestPerimeter = 0.0;
for (int i = 0; i < finalLoops.Count; i++)
{
double loopPerimeter = 0.0;
foreach (IndexSegment line in finalLoops[i])
{
loopPerimeter += line.Extent(ref m_MeshVertices);
}
if (loopPerimeter > largestPerimeter)
{
largestPerimeter = loopPerimeter;
largestPerimeterIdx = i;
}
}
// We need to move the largest loop into the head if it is not
if (largestPerimeterIdx > 0)
{
List <IndexSegment> largestLoop = new List <IndexSegment>(finalLoops[largestPerimeterIdx]);
finalLoops.RemoveAt(largestPerimeterIdx);
finalLoops.Insert(0, largestLoop);
}
}
// Collect the vertices from the list of Edges into list of list of vertices starting with the outer loop (largest loop) following the finalLoop
IList <IList <int> > newFaceVertsLoops = new List <IList <int> >();
foreach (List <IndexSegment> loop in finalLoops)
{
IList <int> newFaceVerts = new List <int>();
foreach (IndexSegment idxSeg in loop)
{
newFaceVerts.Add(idxSeg.StartPindex);
}
if (newFaceVerts.Count > 0)
{
if (newFaceVerts.Count >= 3)
{
newFaceVertsLoops.Add(newFaceVerts);
}
else
{
// Something wrong, a face cannot have less than 3 vertices
Debug.WriteLine("Something went wrong when merging faces resulting with a loop that has less than 3 vertices");
}
}
}
mergedFace = new IndexFace(newFaceVertsLoops, ref m_MeshVertices);
inputFaceList.Remove(currFaceIdx);
// Remove the merged face from segmentOfFaceDict
foreach (KeyValuePair <int, IndexSegment> idxSeg in m_FacesCollDict[currFaceIdx].OuterAndInnerBoundaries)
{
segmentOfFaceDict.Remove(idxSeg.Value);
}
if (m_FacesCollDict.ContainsKey(currFaceIdx))
{
m_FacesCollDict.Remove(currFaceIdx);
}
merged = true;
break; // Once there is an edge merged, create a new face and continue the process of merging
}
int lastFaceID = faceIdxOffset++; // The new index is always the next one in the collection was inserted based on the seq order
if (mergedFace != null)
{
m_FacesCollDict.Add(lastFaceID, mergedFace);
}
if (!merged)
{
// No edge match for this face, add the face into the output face list and move to the next face in the input list
outputFaceList.Add(currProcFace);
if (inputFaceList.Count > 0)
{
firstF = m_FacesCollDict[inputFaceList[0]];
// Remove the merged face from segmentOfFaceDict
foreach (KeyValuePair <int, IndexSegment> idxSeg in firstF.OuterAndInnerBoundaries)
{
segmentOfFaceDict.Remove(idxSeg.Value);
}
currProcFace = inputFaceList[0]; // keep the last processed item
inputFaceList.RemoveAt(0); // remove the first face from the list
merged = false;
// If there is no more face to process, add the merged face into the output list
if (inputFaceList.Count == 0)
{
outputFaceList.Add(currProcFace);
}
}
}
else
{
// If there is no more face to process, add the merged face into the output list
if (inputFaceList.Count == 0)
{
outputFaceList.Add(lastFaceID);
}
// Remove merged face from the Dict
if (m_FacesCollDict.ContainsKey(currProcFace))
{
m_FacesCollDict.Remove(currProcFace);
}
if (inputFaceList.Count > 0)
{
// use the current face as the next face as a merge candidate
firstF = mergedFace;
currProcFace = lastFaceID;
merged = false;
}
}
}
// Finally, there may be multiple faces left because there are multiple disconnected faces at the same normal. Collect them and return
if (segmentOfFaceDict.Count > 0)
{
HashSet <int> indexFaces = new HashSet <int>();
foreach (KeyValuePair <IndexSegment, Tuple <int, int> > segmentFace in segmentOfFaceDict)
{
indexFaces.Add(segmentFace.Value.Item1);
}
foreach (int idxFace in indexFaces)
{
outputFaceList.Add(idxFace);
}
}
}