private void FilterSelfOverlaps(double overlapRadius, bool bResample = true)
{
// [RMS] this tolerance business is not workign properly right now. The problem is
// that decimator loses corners!
// To simplify the computation we are going to resample the curve so that no adjacent
// are within a given distance. Then we can use distance-to-segments, with the two adjacent
// segments filtered out, to measure self-distance
double dist_thresh = overlapRadius;
double sharp_thresh_deg = 45;
//Profiler.Start("InitialResample");
// resample graph. the degenerate-edge thing is necessary to
// filter out tiny segments that are functionally sharp corners,
// but geometrically are made of multiple angles < threshold
// (maybe there is a better way to do this?)
DGraph2Resampler r = new DGraph2Resampler(Graph);
r.CollapseDegenerateEdges(overlapRadius / 10);
if (bResample)
{
r.SplitToMaxEdgeLength(overlapRadius / 2);
r.CollapseToMinEdgeLength(overlapRadius / 3);
}
r.CollapseDegenerateEdges(overlapRadius / 10);
//Profiler.StopAndAccumulate("InitialResample");
//Profiler.Start("SharpCorners");
// find sharp corners
List <int> sharp_corners = new List <int>();
foreach (int vid in Graph.VertexIndices())
{
if (is_fixed_v(vid))
{
continue;
}
double open_angle = Graph.OpeningAngle(vid);
if (open_angle < sharp_thresh_deg)
{
sharp_corners.Add(vid);
}
}
// disconnect at sharp corners
foreach (int vid in sharp_corners)
{
if (Graph.IsVertex(vid) == false)
{
continue;
}
int e0 = Graph.GetVtxEdges(vid)[0];
Index2i ev = Graph.GetEdgeV(e0);
int otherv = (ev.a == vid) ? ev.b : ev.a;
Vector2d newpos = Graph.GetVertex(vid); //0.5 * (Graph.GetVertex(vid) + Graph.GetVertex(otherv));
Graph.RemoveEdge(e0, false);
int newvid = Graph.AppendVertex(newpos);
Graph.AppendEdge(newvid, otherv);
}
//Profiler.StopAndAccumulate("SharpCorners");
//Profiler.Start("HashTable");
// build edge hash table (cell size is just a ballpark guess here...)
edge_hash = new SegmentHashGrid2d <int>(3 * overlapRadius, -1);
foreach (int eid in Graph.EdgeIndices())
{
Segment2d seg = Graph.GetEdgeSegment(eid);
edge_hash.InsertSegment(eid, seg.Center, seg.Extent);
}
if (CollisionGraph.EdgeCount > 0)
{
collision_edge_hash = new SegmentHashGrid2d <int>(3 * CollisionRadius, -1);
foreach (int eid in CollisionGraph.EdgeIndices())
{
Segment2d seg = CollisionGraph.GetEdgeSegment(eid);
collision_edge_hash.InsertSegment(eid, seg.Center, seg.Extent);
}
}
//Profiler.StopAndAccumulate("HashTable");
//Profiler.Start("Erode1");
// Step 1: erode from boundary vertices
List <int> boundaries = new List <int>();
foreach (int vid in Graph.VertexIndices())
{
if (Graph.GetVtxEdgeCount(vid) == 1)
{
boundaries.Add(vid);
}
}
foreach (int vid in boundaries)
{
if (Graph.IsVertex(vid) == false)
{
continue;
}
double dist = MinSelfSegDistance(vid, 2 * dist_thresh);
double collision_dist = MinCollisionConstraintDistance(vid, CollisionRadius);
if (dist < dist_thresh || collision_dist < CollisionRadius)
{
int eid = Graph.GetVtxEdges(vid)[0];
decimate_forward(vid, eid, dist_thresh);
}
}
//Profiler.StopAndAccumulate("Erode1");
//Profiler.Start("OpenAngleSort");
//
// Step 2: find any other possible self-overlaps and erode them.
//
// sort all vertices by opening angle. For any overlap, we can erode
// on either side. Prefer to erode on side with higher curvature.
List <Vector2d> remaining_v = new List <Vector2d>(Graph.MaxVertexID);
foreach (int vid in Graph.VertexIndices())
{
if (is_fixed_v(vid))
{
continue;
}
double open_angle = Graph.OpeningAngle(vid);
if (open_angle == double.MaxValue)
{
continue;
}
remaining_v.Add(new Vector2d(vid, open_angle));
}
remaining_v.Sort((a, b) => { return((a.y < b.y) ? -1 : (a.y > b.y ? 1 : 0)); });
//Profiler.StopAndAccumulate("OpenAngleSort");
//Profiler.Start("Erode2");
// look for overlap vertices. When we find one, erode on both sides.
foreach (Vector2d vinfo in remaining_v)
{
int vid = (int)vinfo.x;
if (Graph.IsVertex(vid) == false)
{
continue;
}
double dist = MinSelfSegDistance(vid, 2 * dist_thresh);
if (dist < dist_thresh)
{
List <int> nbrs = new List <int>(Graph.GetVtxEdges(vid));
foreach (int eid in nbrs)
{
if (Graph.IsEdge(eid)) // may have been decimated!
{
decimate_forward(vid, eid, dist_thresh);
}
}
}
}
//Profiler.StopAndAccumulate("Erode2");
//Profiler.Start("FlatCollapse");
// get rid of extra vertices
r.CollapseFlatVertices(FinalFlatCollapseAngleThreshDeg);
//Profiler.StopAndAccumulate("FlatCollapse");
}
// collapse edges shorter than fMinLen
// NOTE: basically the same as DGraph2Resampler.CollapseToMinEdgeLength, but updates
// our internal caches. Could we merge somehow?
protected void CollapseToMinEdgeLength(DGraph2 graph, double fMinLen)
{
double sharp_threshold_deg = 140.0f;
double minLenSqr = fMinLen * fMinLen;
bool done = false;
int max_passes = 100;
int pass_count = 0;
while (done == false && pass_count++ < max_passes)
{
done = true;
// [RMS] do modulo-indexing here to avoid pathological cases where we do things like
// continually collapse a short edge adjacent to a long edge (which will result in crazy over-collapse)
int N = graph.MaxEdgeID;
const int nPrime = 31337; // any prime will do...
int cur_eid = 0;
do
{
int eid = cur_eid;
cur_eid = (cur_eid + nPrime) % N;
if (!graph.IsEdge(eid))
{
continue;
}
Index2i ev = graph.GetEdgeV(eid);
Vector2d va = graph.GetVertex(ev.a);
Vector2d vb = graph.GetVertex(ev.b);
double distSqr = va.DistanceSquared(vb);
if (distSqr < minLenSqr)
{
int vtx_idx = -1; // collapse to this vertex
// check valences. want to preserve positions of non-valence-2
int na = graph.GetVtxEdgeCount(ev.a);
int nb = graph.GetVtxEdgeCount(ev.b);
if (na != 2 && nb != 2)
{
continue;
}
if (na != 2)
{
vtx_idx = 0;
}
else if (nb != 2)
{
vtx_idx = 1;
}
// check opening angles. want to preserve sharp(er) angles
if (vtx_idx == -1)
{
double opena = Math.Abs(graph.OpeningAngle(ev.a));
double openb = Math.Abs(graph.OpeningAngle(ev.b));
if (opena < sharp_threshold_deg && openb < sharp_threshold_deg)
{
continue;
}
else if (opena < sharp_threshold_deg)
{
vtx_idx = 0;
}
else if (openb < sharp_threshold_deg)
{
vtx_idx = 1;
}
}
Vector2d newPos = (vtx_idx == -1) ? 0.5 * (va + vb) : ((vtx_idx == 0) ? va : vb);
int keep = ev.a, remove = ev.b;
if (vtx_idx == 1)
{
remove = ev.a; keep = ev.b;
}
Vector2d remove_pos = graph.GetVertex(remove);
Vector2d keep_pos = graph.GetVertex(keep);
DGraph2.EdgeCollapseInfo collapseInfo;
if (graph.CollapseEdge(keep, remove, out collapseInfo) == MeshResult.Ok)
{
graph_cache.RemovePointUnsafe(collapseInfo.vRemoved, remove_pos);
last_step_size[collapseInfo.vRemoved] = 0;
graph_cache.UpdatePointUnsafe(collapseInfo.vKept, keep_pos, newPos);
graph.SetVertex(collapseInfo.vKept, newPos);
done = false;
}
}
} while (cur_eid != 0);
}
}
