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moved comp-geom algos to new folder, added GraphSplitter2d, Line2.WhichSide
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6 files changed

+186
-5
lines changed

6 files changed

+186
-5
lines changed

‎curve/Arrangement2d.cs ‎comp_geom/Arrangement2d.cs

File renamed without changes.

‎containment/ConvexHull2.cs ‎comp_geom/ConvexHull2.cs

File renamed without changes.

‎comp_geom/GraphSplitter2d.cs

+148
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,148 @@
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace g3
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{
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public class GraphSplitter2d
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{
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public DGraph2 Graph;
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public double OnVertexTol = MathUtil.Epsilonf;
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public int InsertedEdgesID = 1;
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public Func<Vector2d, bool> InsideTestF = null;
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public GraphSplitter2d(DGraph2 graph)
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{
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Graph = graph;
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}
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DVector<int> EdgeSigns = new DVector<int>();
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struct edge_hit
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{
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public int hit_eid;
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public Index2i vtx_signs;
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public int hit_vid;
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public Vector2d hit_pos;
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public double line_t;
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}
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List<edge_hit> hits = new List<edge_hit>();
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public void InsertCutEdges(Line2d line)
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{
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if (EdgeSigns.Length < Graph.MaxVertexID)
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EdgeSigns.resize(Graph.MaxVertexID);
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foreach ( int vid in Graph.VertexIndices()) {
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EdgeSigns[vid] = line.WhichSide(Graph.GetVertex(vid), OnVertexTol);
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}
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hits.Clear();
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foreach ( int eid in Graph.EdgeIndices() ) {
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Index2i ev = Graph.GetEdgeV(eid);
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Index2i signs = new Index2i(EdgeSigns[ev.a], EdgeSigns[ev.b]);
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if (signs.a * signs.b > 0)
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continue; // both positive or negative, ignore
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edge_hit hit = new edge_hit() { hit_eid = eid, vtx_signs = signs, hit_vid = -1 };
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Vector2d a = Graph.GetVertex(ev.a);
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Vector2d b = Graph.GetVertex(ev.b);
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// parallel-edge case (both are zero)
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if (signs.a == signs.b) {
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if ( a.DistanceSquared(b) > MathUtil.Epsilon ) {
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// we need to somehow not insert a new segment for this span below.
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// so, insert two hit points for the ray-interval, with same eid.
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// This will result in this span being skipped by the same-eid test below
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// *however*, if other edges self-intersect w/ this segment, this will *not work*
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// and duplicate edges will be inserted
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hit.hit_vid = ev.a;
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hit.line_t = line.Project(a);
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hits.Add(hit);
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edge_hit hit2 = hit;
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hit.hit_vid = ev.b;
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hit.line_t = line.Project(b);
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hits.Add(hit);
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} else {
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// degenerate edge - fall through to a == 0 case below
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signs.b = 1;
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}
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}
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if ( signs.a == 0 ) {
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hit.hit_pos = a;
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hit.hit_vid = ev.a;
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hit.line_t = line.Project(a);
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} else if (signs.b == 0 ) {
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hit.hit_pos = b;
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hit.hit_vid = ev.b;
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hit.line_t = line.Project(b);
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} else {
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IntrLine2Segment2 intr = new IntrLine2Segment2(line, new Segment2d(a, b));
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if (intr.Find() == false)
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throw new Exception("GraphSplitter2d.InsertCutEdges: signs are different but ray did not it?");
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if ( intr.IsSimpleIntersection ) {
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hit.hit_pos = intr.Point;
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hit.line_t = intr.Parameter;
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} else {
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throw new Exception("GraphSplitter2d.InsertCutEdges: got parallel edge case!");
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}
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}
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hits.Add(hit);
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}
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// sort by increasing ray-t
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hits.Sort((hit0, hit1) => { return hit0.line_t.CompareTo(hit1.line_t); });
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// insert segments between successive intersection points
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int N = hits.Count;
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for ( int i = 0; i < N-1; ++i ) {
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int j = i + 1;
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// note: skipping parallel segments depends on this eid == eid test (see above)
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if (hits[i].line_t == hits[j].line_t || hits[i].hit_eid == hits[j].hit_eid)
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continue;
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int vi = hits[i].hit_vid;
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if (vi == -1) {
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DGraph2.EdgeSplitInfo split;
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var result = Graph.SplitEdge(hits[i].hit_eid, out split);
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if (result != MeshResult.Ok)
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throw new Exception("GraphSplitter2d.InsertCutEdges: first edge split failed!");
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vi = split.vNew;
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Graph.SetVertex(vi, hits[i].hit_pos);
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}
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int vj = hits[j].hit_vid;
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if ( vj == -1) {
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DGraph2.EdgeSplitInfo split;
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var result = Graph.SplitEdge(hits[j].hit_eid, out split);
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if (result != MeshResult.Ok)
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throw new Exception("GraphSplitter2d.InsertCutEdges: second edge split failed!");
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vj = split.vNew;
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Graph.SetVertex(vj, hits[j].hit_pos);
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}
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// check if we actually want to add this segment
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if ( InsideTestF != null ) {
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Vector2d midpoint = 0.5 * (Graph.GetVertex(vi) + Graph.GetVertex(vj));
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if (InsideTestF(midpoint) == false)
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continue;
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}
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Graph.AppendEdge(vi, vj, InsertedEdgesID);
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}
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}
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}
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}

‎geometry3Sharp.csproj

+3-2
Original file line numberDiff line numberDiff line change
@@ -51,9 +51,10 @@
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<Compile Include="color\ColorHSV.cs" />
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<Compile Include="color\ColorMap.cs" />
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<Compile Include="color\ColorMixer.cs" />
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<Compile Include="comp_geom\GraphSplitter2d.cs" />
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<Compile Include="containment\ContMinBox2.cs" />
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<Compile Include="containment\ContMinCircle2.cs" />
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<Compile Include="containment\ConvexHull2.cs" />
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<Compile Include="comp_geom\ConvexHull2.cs" />
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<Compile Include="core\CommandArgumentSet.cs" />
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<Compile Include="core\DijkstraGraphDistance.cs" />
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<Compile Include="core\DVector.cs" />
@@ -79,7 +80,7 @@
7980
<Compile Include="curve\BSplineBasis.cs" />
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<Compile Include="curve\Circle2.cs" />
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<Compile Include="curve\CurveResampler.cs" />
82-
<Compile Include="curve\Arrangement2d.cs" />
83+
<Compile Include="comp_geom\Arrangement2d.cs" />
8384
<Compile Include="curve\DGraph2Resampler.cs" />
8485
<Compile Include="curve\DGraph2Util.cs" />
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<Compile Include="curve\Ellipse2.cs" />

‎intersection/IntrLine2Segment2.cs

+5-3
Original file line numberDiff line numberDiff line change
@@ -67,9 +67,11 @@ public bool IsSimpleIntersection {
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get { return Result == IntersectionResult.Intersects && Type == IntersectionType.Point; }
6868
}
6969

70-
// these values are on the line
71-
public Vector2d Point; // only set if Quantity = 1
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public double Parameter; // only set if Quantity = 1
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/// <summary> Point on line, only set if Quantity = 1 </summary>
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public Vector2d Point;
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/// <summary>Parameter along line, only set if Quanityt = 1 </summary>
74+
public double Parameter;
7375

7476
public IntrLine2Segment2(Line2d line, Segment2d seg)
7577
{

‎math/Line2.cs

+30
Original file line numberDiff line numberDiff line change
@@ -33,6 +33,36 @@ public double DistanceSquared(Vector2d p)
3333
return (proj - p).LengthSquared;
3434
}
3535

36+
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/// <summary>
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/// Returns:
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/// +1, on right of line
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/// -1, on left of line
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/// 0, on the line
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/// </summary>
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public int WhichSide(Vector2d test, double tol = 0)
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{
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double x0 = test.x - Origin.x;
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double y0 = test.y - Origin.y;
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double x1 = Direction.x;
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double y1 = Direction.y;
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double det = x0 * y1 - x1 * y0;
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return (det > tol ? +1 : (det < -tol ? -1 : 0));
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}
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public int WhichSide(ref Vector2d test, double tol = 0)
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{
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double x0 = test.x - Origin.x;
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double y0 = test.y - Origin.y;
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double x1 = Direction.x;
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double y1 = Direction.y;
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double det = x0 * y1 - x1 * y0;
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return (det > tol ? +1 : (det < -tol ? -1 : 0));
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}
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// conversion operators
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public static implicit operator Line2d(Line2f v)
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{

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