private void DetectIntersectSegments(List <Vector2d> footprint, Vector2d start, Vector2d end,
out Vector2d first, out int firstIndex, out Vector2d second, out int secondIndex)
{
firstIndex = -1;
secondIndex = -1;
first = default(Vector2d);
second = default(Vector2d);
for (int i = 0; i < footprint.Count; i++)
{
var p1 = footprint[i];
var p2 = footprint[i == footprint.Count - 1 ? 0 : i + 1];
double r;
if (Vector2dUtils.LineIntersects(start, end, p1, p2, out r))
{
var intersectionPoint = Vector2dUtils.GetPointAlongLine(p1, p2, r);
if (firstIndex == -1)
{
firstIndex = i;
first = intersectionPoint;
}
else
{
secondIndex = i;
second = intersectionPoint;
break;
}
}
}
}
/// <summary> Tries to find intersection with transit walls. </summary>
private static bool HasIntersectPoint(List <Wall> extrudedWalls,
List <Wall> connectedSkeletonWalls, Vector2d p1, Vector2d p2,
out Vector2d intersectPoint, out int transitWallIndex)
{
intersectPoint = new Vector2d();
transitWallIndex = -1;
var distance = double.MaxValue;
for (var i = 0; i < extrudedWalls.Count; i++)
{
var wall = extrudedWalls[i];
if (wall.IsOuter)
{
continue;
}
var start = wall.Start;
var end = wall.End;
double r;
if (!Vector2dUtils.LineIntersects(p1, p2, start, end, out r))
{
continue;
}
var currIntersectPoint = new Vector2d(
Math.Round(p1.X + (r * (p2.X - p1.X))),
Math.Round((p1.Y + (r * (p2.Y - p1.Y)))));
// skip intersections of skeleton edges which are connected with footprint
var skip = false;
foreach (var connectedWall in connectedSkeletonWalls)
{
if (Vector2dUtils.LineIntersects(p1, currIntersectPoint,
connectedWall.Start, connectedWall.End, out r))
{
skip = true;
break;
}
}
if (skip)
{
continue;
}
if (Vector2dUtils.IsPointOnSegment(start, end, currIntersectPoint))
{
var currDistance = p1.DistanceTo(currIntersectPoint);
if (currDistance > 0 && currDistance < distance)
{
intersectPoint = currIntersectPoint;
transitWallIndex = i;
distance = currDistance;
}
}
}
return(transitWallIndex != -1);
}
public void CanDetectIntersection()
{
// ARRANGE
var s1 = new Vector2d(0, 0);
var e1 = new Vector2d(10, 10);
var s2 = new Vector2d(10, 0);
var e2 = new Vector2d(0, 10);
double r;
// ACT
var result = Vector2dUtils.LineIntersects(s1, e1, s2, e2, out r);
var currIntersectPoint = Vector2dUtils.GetPointAlongLine(s1, s2, r);
// ASSERT
Assert.IsTrue(result);
Assert.IsTrue(Math.Abs(currIntersectPoint.X - 5) < MathUtils.Epsion);
Assert.IsTrue(Math.Abs(currIntersectPoint.X - 5) < MathUtils.Epsion);
}