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public static SlicePolygon ( Polygon p, Circle c, List |
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| p | Polygon | |
| c | Circle | |
| output | List |
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| return | bool | |
private static void SlicePolygonHelper(Polygon p, CircleNE c1, CircleNE c2, out List <Polygon> output)
{
output = new List <Polygon>();
// ZZZ - alter Clip method to work on Polygons and use that.
// Slice it up.
List <Polygon> sliced1, sliced2;
Slicer.SlicePolygon(p, c1, out sliced1);
Slicer.SlicePolygon(p, c2, out sliced2);
// Keep the ones we want.
foreach (Polygon newPoly in sliced1)
{
bool outside = !c1.IsPointInsideNE(newPoly.CentroidApprox);
if (outside)
{
output.Add(newPoly);
}
}
foreach (Polygon newPoly in sliced2)
{
bool inside = c2.IsPointInsideNE(newPoly.CentroidApprox);
if (inside)
{
output.Add(newPoly);
}
}
}
/// <summary>
/// Slices a polygon by a circle with some thickness.
/// Input circle may be a line.
/// </summary>
/// <remarks>The input polygon might get reversed</remarks>
public static void SlicePolygon(Polygon p, CircleNE c, Geometry g, double thickness, out List <Polygon> output)
{
output = new List <Polygon>();
// Setup the two slicing circles.
CircleNE c1 = c.Clone(), c2 = c.Clone();
Mobius m = new Mobius();
Vector3D pointOnCircle = c.IsLine ? c.P1 : c.Center + new Vector3D(c.Radius, 0);
m.Hyperbolic2(g, c1.CenterNE, pointOnCircle, thickness / 2);
c1.Transform(m);
m.Hyperbolic2(g, c2.CenterNE, pointOnCircle, -thickness / 2);
c2.Transform(m);
// ZZZ - alter Clip method to work on Polygons and use that.
// Slice it up.
List <Polygon> sliced1, sliced2;
Slicer.SlicePolygon(p, c1, out sliced1);
Slicer.SlicePolygon(p, c2, out sliced2);
// Keep the ones we want.
foreach (Polygon newPoly in sliced1)
{
bool outside = !c1.IsPointInsideNE(newPoly.CentroidApprox);
if (outside)
{
output.Add(newPoly);
}
}
foreach (Polygon newPoly in sliced2)
{
bool inside = c2.IsPointInsideNE(newPoly.CentroidApprox);
if (inside)
{
output.Add(newPoly);
}
}
}
/// <summary>
/// Clip the drawn polygons in a set of tiles, using a circle.
/// </summary>
public static void Clip(ref List <Tile> tiles, Circle c, bool keepInside)
{
List <Tile> newTiles = new List <Tile>();
foreach (Tile t in tiles)
{
List <Polygon> sliced;
Slicer.SlicePolygon(t.Drawn, c, out sliced);
foreach (Polygon p in sliced)
{
bool insideCircle = (p.CentroidApprox - c.Center).Abs() < c.Radius;
if ((keepInside && insideCircle) || (!keepInside && !insideCircle))
{
newTiles.Add(new Tile(t.Boundary, p, t.Geometry));
}
}
}
tiles = newTiles;
}