private static Point otherOf(Triangle a, Segment common) {
Point otherOfA = null;
for (Point p : a) {
if (!common.getP1().equals(p) && !common.getP2().equals(p)) {
otherOfA = p;
break;
}
}
assert (otherOfA != null) : format("Broken triangle %s common %s!", a, common);
return otherOfA;
}
public static boolean swap(Set<Triangle> triangles, Triangle a, Triangle b, Segment common) {
Point otherOfA = otherOf(a, common);
Point otherOfB = otherOf(b, common);
Line ab = Line.defineByPoints(otherOfA, otherOfB);
if (ab.distance(common.getP1()).doubleValue() < 0.001
|| ab.distance(common.getP2()).doubleValue() < 0.001) {
return false;
}
Triangle t1;
Triangle t2;
if (TriangleUtils.counterClockwise(otherOfA, otherOfB, common.getP1()) < 0) {
t1 = new Triangle(otherOfA, otherOfB, common.getP1());
t2 = new Triangle(otherOfA, common.getP2(), otherOfB);
} else {
t1 = new Triangle(otherOfB, otherOfA, common.getP1());
t2 = new Triangle(otherOfB, common.getP2(), otherOfA);
}
BigDecimal oldArea = a.area().add(b.area(), DECIMAL128).setScale(MY_SCALE, MY_RND);
BigDecimal newArea = t1.area().add(t2.area(), DECIMAL128).setScale(MY_SCALE, MY_RND);
if (oldArea.compareTo(newArea) == 0) {
triangles.remove(a);
triangles.remove(b);
triangles.add(t1);
triangles.add(t2);
return true;
}
return false;
}