bool Circle::IntersectsDisc(const LineSegment &lineSegment) const
{
float d;
bool intersectsPlane = lineSegment.Intersects(ContainingPlane(), &d);
if (intersectsPlane)
return false;
return lineSegment.GetPoint(d).DistanceSq(pos) <= r*r;
}
bool Polygon::IsSimple() const
{
assume(IsPlanar());
Plane plane = PlaneCCW();
for(int i = 0; i < (int)p.size(); ++i)
{
LineSegment si = plane.Project(Edge(i));
for(int j = i+2; j < (int)p.size(); ++j)
{
if (i == 0 && j == (int)p.size() - 1)
continue; // These two edges are consecutive and share a vertex. Don't check that pair.
LineSegment sj = plane.Project(Edge(j));
if (si.Intersects(sj))
return false;
}
}
return true;
}
bool Polygon::Intersects2D(const LineSegment &localSpaceLineSegment) const
{
if (p.size() < 3)
return false;
const vec basisU = BasisU();
const vec basisV = BasisV();
const vec origin = p[0];
LineSegment edge;
edge.a = POINT_VEC(Dot(p.back(), basisU), Dot(p.back(), basisV), 0); // map to 2D
for (int i = 0; i < (int)p.size(); ++i)
{
edge.b = POINT_VEC(Dot(p[i], basisU), Dot(p[i], basisV), 0); // map to 2D
if (edge.Intersects(localSpaceLineSegment))
return true;
edge.a = edge.b;
}
// The line segment did not intersect with any of the polygon edges, so either the whole line segment is inside
// the polygon, or it is fully outside the polygon. Test one point of the line segment to determine which.
return Contains(MapFrom2D(localSpaceLineSegment.a.xy()));
}
