public static bool SegmentsIntersecting(gvec2 p0, gvec2 p1, gvec2 pa, gvec2 pb)
{
gvec2 dir0 = p1 - p0;
gvec2 dir1 = pb - pa;
{
gvec2 dir0n = dir0.Normalized;
gvec2 dir1n = dir1.Normalized;
if ((dir0n.x.cmp(dir1n.x) && dir0n.y.cmp(dir1n.y)) || (dir0n.x.cmp(-dir1n.x) && dir0n.y.cmp(-dir1n.y)))
{
return(false);
}
}
double t0 =
((dir1.x) * (p0.y - pa.y) - (dir1.y) * (p0.x - pa.x)) /
((dir1.y) * (dir0.x) - (dir1.x) * (dir0.y));
if (t0 < 0 || t0 >= 1)
{
return(false);
}
double t1 =
((dir0.x) * (p0.y - pa.y) - (dir0.y) * (p0.x - pa.x)) /
((dir1.y) * (dir0.x) - (dir1.x) * (dir0.y));
if (t1 < 0 || t1 >= 1)
{
return(false);
}
return(true);
}
public static bool SegmentsIntersecting(gvec2 p0, gvec2 p1, gvec2 pa, gvec2 pb, ref gvec2 intersection, ref double parameter0, ref double parameter1)
{
gvec2 dir0 = p1 - p0;
gvec2 dir1 = pb - pa;
{
gvec2 dir0n = dir0.Normalized;
gvec2 dir1n = dir1.Normalized;
if ((dir0n.x.cmp(dir1n.x) && dir0n.y.cmp(dir1n.y)) || (dir0n.x.cmp(-dir1n.x) && dir0n.y.cmp(-dir1n.y)))
{
return(false);
}
}
parameter0 =
((dir1.x) * (p0.y - pa.y) - (dir1.y) * (p0.x - pa.x)) /
((dir1.y) * (dir0.x) - (dir1.x) * (dir0.y));
if (parameter0 < 0 || parameter0 >= 1)
{
return(false);
}
parameter1 =
((dir0.x) * (p0.y - pa.y) - (dir0.y) * (p0.x - pa.x)) /
((dir1.y) * (dir0.x) - (dir1.x) * (dir0.y));
if (parameter1 < 0 || parameter1 >= 1)
{
return(false);
}
intersection = dir0 * parameter0 + p0;
return(true);
}
public bool IsPointInside(gvec2 point)
{
return(point.x >= ll.x && point.x < ur.x && point.y >= ll.y && point.y < ur.y);
}
public static bool PointInCCWTriangle(gvec2 pt, gvec2 v0, gvec2 v1, gvec2 v2) => IsCCW(pt, v0, v1) && IsCCW(pt, v1, v2) && IsCCW(pt, v2, v0);
public static bool IsCCW(gvec2 v0, gvec2 v1, gvec2 v2) => (v1.x - v0.x) * (v1.y + v0.y) + (v2.x - v1.x) * (v2.y + v1.y) + (v0.x - v2.x) * (v0.y + v2.y) <= 0;
