Optimize the contour creation.
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1 changed files with 12 additions and 16 deletions
28
Region.cs
28
Region.cs
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@ -151,38 +151,33 @@ namespace Boprs
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// Lexico-graphically sort the vertices.
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// Lexico-graphically sort the vertices.
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vertices.Sort();
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vertices.Sort();
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// Sweepline to keep track of edges.
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SweepLine sweepLine = new SweepLine();
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bool[] processed = new bool[vertices.Count];
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bool[] processed = new bool[vertices.Count];
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List<Contour> contours = new List<Contour>();
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List<Contour> contours = new List<Contour>();
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for(int i = 0; i < vertices.Count; i++)
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for(int i = 0; i < vertices.Count; i++)
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{
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{
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SweepVertex acVx = vertices[i];
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// If we already traversed this vertex, skip it.
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if (acVx.IsLeft())
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{
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sweepLine.Add(acVx.Edge, false);
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}
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else
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{
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sweepLine.Remove(acVx.Edge);
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}
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if (processed[i])
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if (processed[i])
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{
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{
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continue;
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continue;
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}
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}
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// Otherwise this is an edge on an indiscovered contour, create it.
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Contour contour = new Contour();
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Contour contour = new Contour();
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contours.Add(contour);
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contours.Add(contour);
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SweepEdge prev = sweepLine.PrevEdge(acVx.Edge);
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// acVx should be guaranteed to be the lowest and leftest vertex of the new polygon.
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bool shouldBeCW = prev == null ? false : prev.TransitionInside;
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// Thus it cannot be vertical.
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// if it is transition inside, it is a positive contour and should wind counter-clockwise,
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// if it is transition outside, it is a negative contour and should wind clockwise.
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SweepVertex acVx = vertices[i];
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bool shouldBeCW = !acVx.Edge.TransitionInside;
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Point2d target = acVx.Point;
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Point2d target = acVx.Point;
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// Traverse connected edges, and mark taversed vertices as processed,
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// until we loop back to the first discovered vertex on the contour.
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int pos = i;
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int pos = i;
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processed[i] = true;
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processed[i] = true;
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contour.Vertices.Add(vertices[pos].Point);
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contour.Vertices.Add(vertices[pos].Point);
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@ -200,6 +195,7 @@ namespace Boprs
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}
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}
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processed[vertices.IndexOf(vertices[pos].OtherVertex())] = true;
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processed[vertices.IndexOf(vertices[pos].OtherVertex())] = true;
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// If the contour is a hole and winds ccw, or positive and winds cw, flip it.
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if (shouldBeCW != contour.IsClockwise())
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if (shouldBeCW != contour.IsClockwise())
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{
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{
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contour.Reverse();
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contour.Reverse();
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