public int Compare(BasicObstacleSide first, BasicObstacleSide second)
{
ValidateArg.IsNotNull(first, "first");
ValidateArg.IsNotNull(second, "second");
// If these are two sides of the same obstacle then the ordering is obvious.
if (first.Obstacle == second.Obstacle)
{
if (first == second)
{
return(0);
}
return((first is LowObstacleSide) ? -1 : 1);
}
Debug_VerifySidesDoNotIntersect(first, second);
// Other than intersecting sides at vertices of the same obstacle, there should be no interior intersections...
Point firstIntersect = VisibilityGraphGenerator.ScanLineIntersectSide(this.linePositionAtLastInsertOrRemove, first, scanDirection);
Point secondIntersect = VisibilityGraphGenerator.ScanLineIntersectSide(this.linePositionAtLastInsertOrRemove, second, scanDirection);
var cmp = firstIntersect.CompareTo(secondIntersect);
// ... but we may still have rectangular sides that coincide, or angled sides that are close enough here but
// are not detected by the convex-hull overlap calculations. In those cases, we refine the comparison by side
// type, with High coming before Low, and then by obstacle ordinal if needed. Because there are no interior
// intersections, this ordering will remain valid as long as the side(s) are in the scanline.
if (0 == cmp)
{
bool firstIsLow = first is LowObstacleSide;
bool secondIsLow = second is LowObstacleSide;
cmp = firstIsLow.CompareTo(secondIsLow);
if (0 == cmp)
{
cmp = first.Obstacle.Ordinal.CompareTo(second.Obstacle.Ordinal);
}
}
DevTraceInfo(4, "Compare {0} @ {1:F5} {2:F5} and {3:F5} {4:F5}: {5} {6}",
cmp, firstIntersect.X, firstIntersect.Y, secondIntersect.X, secondIntersect.Y, first, second);
return(cmp);
}
