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Identified a new failure mode for polygons.

This commit is contained in:
Luc Maisonobe 2014-11-30 11:40:27 +01:00
parent e11c00085c
commit c29e3d681f
1 changed files with 37 additions and 0 deletions
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37
src/test/java/org/apache/commons/math3/geometry/euclidean/twod/PolygonsSetTest.java
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@ -24,6 +24,7 @@ import org.apache.commons.math3.geometry.euclidean.oned.IntervalsSet;
import org.apache.commons.math3.geometry.euclidean.oned.Vector1D;
import org.apache.commons.math3.geometry.partitioning.BSPTree;
import org.apache.commons.math3.geometry.partitioning.BoundaryProjection;
import org.apache.commons.math3.geometry.partitioning.Hyperplane;
import org.apache.commons.math3.geometry.partitioning.Region;
import org.apache.commons.math3.geometry.partitioning.Region.Location;
import org.apache.commons.math3.geometry.partitioning.RegionFactory;
@ -1107,6 +1108,42 @@ public class PolygonsSetTest {
}
@Test
public void testThinRectangle() {
RegionFactory<Euclidean2D> factory = new RegionFactory<Euclidean2D>();
Vector2D pA = new Vector2D(0.0, 1.0);
Vector2D pB = new Vector2D(0.0, 0.0);
Vector2D pC = new Vector2D(1.0 / 64.0, 0.0);
Vector2D pD = new Vector2D(1.0 / 64.0, 1.0);
// if tolerance is smaller than rectangle width, the rectangle is computed accurately
Hyperplane<Euclidean2D>[] h1 = new Line[] {
new Line(pA, pB, 1.0 / 256),
new Line(pB, pC, 1.0 / 256),
new Line(pC, pD, 1.0 / 256),
new Line(pD, pA, 1.0 / 256)
};
Region<Euclidean2D> accuratePolygon = factory.buildConvex(h1);
Assert.assertEquals(1.0 / 64.0, accuratePolygon.getSize(), 1.0e-10);
Assert.assertTrue(Double.isInfinite(new RegionFactory<Euclidean2D>().getComplement(accuratePolygon).getSize()));
Assert.assertEquals(2 * (1.0 + 1.0 / 64.0), accuratePolygon.getBoundarySize(), 1.0e-10);
// if tolerance is larger than rectangle width, the rectangle degenerates
// as of 3.3, its two long edges cannot be distinguished anymore and this part of the test fails
Hyperplane<Euclidean2D>[] h2 = new Line[] {
new Line(pA, pB, 1.0 / 16),
new Line(pB, pC, 1.0 / 16),
new Line(pC, pD, 1.0 / 16),
new Line(pD, pA, 1.0 / 16)
};
Region<Euclidean2D> degeneratedPolygon = factory.buildConvex(h2);
Assert.assertEquals(1.0 / 64.0, degeneratedPolygon.getSize(), 1.0e-10);
Assert.assertTrue(Double.isInfinite(new RegionFactory<Euclidean2D>().getComplement(degeneratedPolygon).getSize()));
Assert.assertEquals(2 * (1.0 + 1.0 / 64.0), degeneratedPolygon.getBoundarySize(), 1.0e-10);
}
private PolygonsSet buildSet(Vector2D[][] vertices) {
ArrayList<SubHyperplane<Euclidean2D>> edges = new ArrayList<SubHyperplane<Euclidean2D>>();
for (int i = 0; i < vertices.length; ++i) {