public bool Intersect(Circle c, out Vector2[] pts)
{
// iterate through the points and find all intersections
Vector2[] pt_temp;
List <Vector2> pt_list = new List <Vector2>();
for (int i = 0; i < points.Count - 1; i++)
{
LineSegment ls = new LineSegment(points[i], points[i + 1]);
if (ls.Intersect(c, out pt_temp))
{
pt_list.AddRange(pt_temp);
}
}
LineSegment ls1 = new LineSegment(points[0], points[points.Count - 1]);
if (ls1.Intersect(c, out pt_temp))
{
pt_list.AddRange(pt_temp);
}
pts = pt_list.ToArray();
return(pts.Length > 0);
}
public bool Intersect(Line l, out Vector2[] pts, out double[] K)
{
// go through and label each point on the "left" or "right" of the line
bool[] pt_side = new bool[points.Count];
Vector2 s = l.P1 - l.P0;
for (int i = 0; i < points.Count; i++)
{
Vector2 t = points[i] - l.P0;
pt_side[i] = s.Cross(t) < 0;
}
// figure out any pairs spanning the line
List <Vector2> pt_list = new List <Vector2>();
List <double> K_list = new List <double>();
for (int i = 0; i < points.Count - 1; i++)
{
if (pt_side[i] != pt_side[i + 1])
{
// this is a cross, check for intersection
LineSegment ls = new LineSegment(points[i], points[i + 1]);
Vector2 pt_temp, K_temp;
if (ls.Intersect(l, out pt_temp, out K_temp))
{
pt_list.Add(pt_temp);
K_list.Add(K_temp.Y);
}
}
}
// check the start/end pair
if (pt_side[0] != pt_side[pt_side.Length - 1])
{
LineSegment ls = new LineSegment(points[0], points[points.Count - 1]);
Vector2 pt_temp, K_temp;
if (ls.Intersect(l, out pt_temp, out K_temp))
{
pt_list.Add(pt_temp);
K_list.Add(K_temp.Y);
}
}
pts = pt_list.ToArray();
K = K_list.ToArray();
return(pts.Length > 0);
}
private bool DoSegmentsCollide(IPathSegment seg1, IPathSegment seg2, out double collideDist1, out double collideDist2)
{
bool doesIntersect = false;
Vector2 intersectPoint;
Vector2[] p = new Vector2[4];
collideDist1 = Double.MaxValue;
collideDist2 = Double.MaxValue;
LineSegment ls1 = new LineSegment(seg1.Start, seg1.End);
LineSegment ls2 = new LineSegment(seg2.Start, seg2.End);
doesIntersect = ls1.Intersect(ls2, out intersectPoint);
p[0] = ls1.ClosestPoint(seg2.Start);
p[1] = ls1.ClosestPoint(seg2.End);
p[2] = ls2.ClosestPoint(seg1.Start);
p[3] = ls2.ClosestPoint(seg1.End);
if (doesIntersect)
{
collideDist1 = seg1.Start.DistanceTo(intersectPoint);
collideDist2 = seg2.Start.DistanceTo(intersectPoint);
}
if ((p[0] - seg2.Start).Length < collideThreshold)
{
if (collideDist1 > seg1.Start.DistanceTo(p[0]))
{
collideDist1 = seg1.Start.DistanceTo(p[0]);
collideDist2 = 0;
doesIntersect = true;
}
}
if ((p[1] - seg2.End).Length < collideThreshold)
{
if (collideDist1 > seg1.Start.DistanceTo(p[1]))
{
collideDist1 = seg1.Start.DistanceTo(p[1]);
collideDist2 = seg2.Length;
doesIntersect = true;
}
}
if ((p[2] - seg1.Start).Length < collideThreshold)
{
collideDist1 = 0;
collideDist2 = seg2.Start.DistanceTo(p[2]);
}
if ((p[3] - seg1.End).Length < collideThreshold)
{
if (collideDist1 > seg1.Length)
{
collideDist1 = seg1.Length;
collideDist2 = seg2.Start.DistanceTo(p[3]);
}
}
return doesIntersect;
}
public bool Intersect(LineSegment l, out Vector2 pts, out Vector2 K)
{
return(l.Intersect(this, out pts, out K));
}
