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MATH-1436: adding checks for edge cases related to infinite lines in PolygonsSet; adding two test cases to PolygonsSetTest

This commit is contained in:
darkma773r 2017-12-23 14:17:12 -05:00
parent eafb16c711
commit b657c914c0
2 changed files with 99 additions and 28 deletions
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63
src/main/java/org/apache/commons/math4/geometry/euclidean/twod/PolygonsSet.java
View File

@ -644,7 +644,11 @@ public class PolygonsSet extends AbstractRegion<Euclidean2D, Euclidean1D> {
for (ConnectableSegment s = getUnprocessed(segments); s != null; s = getUnprocessed(segments)) {
final List<Segment> loop = followLoop(s);
if (loop != null) {
if (loop.get(0).getStart() == null) {
// an open loop is one that has fewer than two segments or has a null
// start point; the case where we have two segments in a closed loop
// (ie, an infinitely thin, degenerate loop) will result in null being
// returned from the followLoops method
if (loop.size() < 2 || loop.get(0).getStart() == null) {
// this is an open loop, we put it on the front
loops.add(0, loop);
} else {
@ -863,18 +867,22 @@ public class PolygonsSet extends AbstractRegion<Euclidean2D, Euclidean1D> {
* @param loop segments loop to filter (will be modified in-place)
*/
private void filterSpuriousVertices(final List<Segment> loop) {
for (int i = 0; i < loop.size(); ++i) {
final Segment previous = loop.get(i);
int j = (i + 1) % loop.size();
final Segment next = loop.get(j);
if (next != null &&
Precision.equals(previous.getLine().getAngle(), next.getLine().getAngle(), Precision.EPSILON)) {
// the vertex between the two edges is a spurious one
// replace the two segments by a single one
loop.set(j, new Segment(previous.getStart(), next.getEnd(), previous.getLine()));
loop.remove(i--);
}
}
// we need at least 2 segments in order for one of the contained vertices
// to be unnecessary
if (loop.size() > 1) {
for (int i = 0; i < loop.size(); ++i) {
final Segment previous = loop.get(i);
int j = (i + 1) % loop.size();
final Segment next = loop.get(j);
if (next != null &&
Precision.equals(previous.getLine().getAngle(), next.getLine().getAngle(), Precision.EPSILON)) {
// the vertex between the two edges is a spurious one
// replace the two segments by a single one
loop.set(j, new Segment(previous.getStart(), next.getEnd(), previous.getLine()));
loop.remove(i--);
}
}
}
}
/** Private extension of Segment allowing connection. */
@ -1067,23 +1075,26 @@ public class PolygonsSet extends AbstractRegion<Euclidean2D, Euclidean1D> {
/** Select the node whose cut sub-hyperplane is closest to specified point.
* @param point reference point
* @param candidates candidate nodes
* @return node closest to point, or null if no node is closer than tolerance
* @return node closest to point, or null if point is null or no node is closer than tolerance
*/
private BSPTree<Euclidean2D> selectClosest(final Cartesian2D point, final Iterable<BSPTree<Euclidean2D>> candidates) {
if (point != null) {
BSPTree<Euclidean2D> selected = null;
double min = Double.POSITIVE_INFINITY;
BSPTree<Euclidean2D> selected = null;
double min = Double.POSITIVE_INFINITY;
for (final BSPTree<Euclidean2D> node : candidates) {
final double distance = FastMath.abs(node.getCut().getHyperplane().getOffset(point));
if (distance < min) {
selected = node;
min = distance;
}
}
return min <= tolerance ? selected : null;
for (final BSPTree<Euclidean2D> node : candidates) {
final double distance = FastMath.abs(node.getCut().getHyperplane().getOffset(point));
if (distance < min) {
selected = node;
min = distance;
}
}
if (min <= tolerance) {
return selected;
}
}
return null;
}
/** Get the segments.

60
src/test/java/org/apache/commons/math4/geometry/euclidean/twod/PolygonsSetTest.java
View File

@ -96,6 +96,61 @@ public class PolygonsSetTest {
Assert.assertTrue(Double.isInfinite(box.getSize()));
}
@Test
public void testSingleInfiniteLine() {
// arrange
double tolerance = 1e-10;
Line line = new Line(new Cartesian2D(0, 0), new Cartesian2D(1, 1), tolerance);
List<SubHyperplane<Euclidean2D>> boundaries = new ArrayList<SubHyperplane<Euclidean2D>>();
boundaries.add(line.wholeHyperplane());
// act
PolygonsSet polygon = new PolygonsSet(boundaries, tolerance);
// assert
Assert.assertTrue(Double.isInfinite(polygon.getSize()));
Cartesian2D[][] vertices = polygon.getVertices();
Assert.assertEquals(1, vertices.length);
Cartesian2D[] loop = vertices[0];
Assert.assertEquals(3, loop.length);
Assert.assertEquals(null, loop[0]);
checkPointsEqual(line.toSpace(new Cartesian1D(-Float.MAX_VALUE)), loop[1], tolerance);
checkPointsEqual(line.toSpace(new Cartesian1D(Float.MAX_VALUE)), loop[2], tolerance);
}
@Test
public void testMixOfFiniteAndInfiniteBoundaries() {
// arrange
double tolerance = 1e-10;
Line line = new Line(new Cartesian2D(1, 0), new Cartesian2D(1, 1), tolerance);
List<SubHyperplane<Euclidean2D>> boundaries = new ArrayList<SubHyperplane<Euclidean2D>>();
boundaries.add(buildSegment(new Cartesian2D(0, 1), new Cartesian2D(0, 0)));
boundaries.add(buildSegment(new Cartesian2D(0, 0), new Cartesian2D(1, 0)));
boundaries.add(new SubLine(line, new IntervalsSet(0, Double.POSITIVE_INFINITY, tolerance)));
// act
PolygonsSet polygon = new PolygonsSet(boundaries, tolerance);
// assert
Assert.assertTrue(Double.isInfinite(polygon.getSize()));
Cartesian2D[][] vertices = polygon.getVertices();
Assert.assertEquals(1, vertices.length);
Cartesian2D[] loop = vertices[0];
Assert.assertEquals(5, loop.length);
Assert.assertEquals(null, loop[0]);
checkPointsEqual(new Cartesian2D(0, 1), loop[1], tolerance);
checkPointsEqual(new Cartesian2D(0, 0), loop[2], tolerance);
checkPointsEqual(new Cartesian2D(1, 0), loop[3], tolerance);
checkPointsEqual(new Cartesian2D(1, 0), loop[4], tolerance);
}
@Test
public void testStair() {
Cartesian2D[][] vertices = new Cartesian2D[][] {
@ -1273,6 +1328,11 @@ public class PolygonsSetTest {
return new SubLine(line, new IntervalsSet(lower, upper, 1.0e-10));
}
private void checkPointsEqual(Cartesian2D expected, Cartesian2D actual, double tolerance) {
Assert.assertEquals(expected.getX(), actual.getX(), tolerance);
Assert.assertEquals(expected.getY(), actual.getY(), tolerance);
}
private void checkPoints(Region.Location expected, PolygonsSet set,
Cartesian2D[] points) {
for (int i = 0; i < points.length; ++i) {