// assumes p is ccw ordered, edge is counted as interior (neither case)
public static bool SegmentIntersectsNonDegenerateConvexPolygonInterior(IntLineSegment2 s, IntVector2[] p)
{
#if DEBUG
if (Clockness(p[0], p[1], p[2]) == Clk.Clockwise)
{
throw new BadInputException("p not ccw");
}
if (p.Length < 3)
{
throw new BadInputException("len(p) < 3");
}
#endif
var(x, y) = s;
bool xInterior = true, yInterior = true;
IntVector2 a = p[p.Length - 1], b;
int i = 0;
for (; i < p.Length && (xInterior || yInterior); i++, a = b)
{
b = p[i];
var abx = Clockness(a, b, x);
var aby = Clockness(a, b, y);
if (abx == Clk.Clockwise && aby == Clk.Clockwise)
{
return(false);
}
xInterior &= abx != Clk.Clockwise;
yInterior &= aby != Clk.Clockwise;
if (abx == (Clk)(-(int)aby) || abx == Clk.Neither || aby == Clk.Neither)
{
// The below is equivalent to:
// // (a, b) places x, y onto opposite half-planes.
// // Intersect if (x, y) places a, b onto opposite half-planes.
// var xya = Clockness(x, y, a);
// var xyb = Clockness(x, y, b);
// if (xya != xyb || xya == Clk.Neither || xyb == Clk.Neither) return true;
if (IntLineSegment2.Intersects(a.X, a.Y, b.X, b.Y, x.X, x.Y, y.X, y.Y))
{
return(true);
}
}
}
for (; i < p.Length; i++, a = b)
{
b = p[i];
if (IntLineSegment2.Intersects(a.X, a.Y, b.X, b.Y, x.X, x.Y, y.X, y.Y))
{
return(true);
}
}
return(xInterior && yInterior);
}
public static bool SegmentIntersectsConvexPolygonInterior(IntLineSegment2 s, IntVector2[] p)
{
if (p.Length == 1)
{
return(false);
}
else if (p.Length == 2)
{
return(s.Intersects(new IntLineSegment2(p[0], p[1])));
}
else
{
return(SegmentIntersectsNonDegenerateConvexPolygonInterior(s, p));
}
}
public static PolygonContainmentResult SegmentInPolygon(this PolyNode node, IntLineSegment2 query)
{
var bvh = node.visibilityGraphNodeData.ContourBvh;
if (bvh != null)
{
if (bvh.Intersects(ref query))
{
return(PolygonContainmentResult.IntersectsPolygon);
}
}
else
{
var last = node.Contour[node.Contour.Count - 1];
var q1 = query.First;
var q2 = query.Second;
for (var i = 0; i < node.Contour.Count; i++)
{
var current = node.Contour[i];
if ((current == q1 && last == q2) || (current == q2 && last == q1))
{
return(PolygonContainmentResult.OnPolygon);
}
if (IntLineSegment2.Intersects(current.X, current.Y, last.X, last.Y, q1.X, q1.Y, q2.X, q2.Y))
{
return(PolygonContainmentResult.IntersectsPolygon);
}
last = current;
}
}
// Query segment isn't on-contour or intersecting the contour, so it's either fully in or out.
var endpointContainment = Clipper.PointInPolygon(query.First, node.Contour);
if (endpointContainment == PolygonContainmentResult.OnPolygon)
{
return(PolygonContainmentResult.IntersectsPolygon);
}
return(endpointContainment);
}