Given a point p and vector v, find the unit normal at the first point where the ray r(t)=p+tv intersects the given shape S. If there are no intersections, returns (0,0).
A shape (Circle, Rect, Line, Polyline, Polygon, Ellipse, or Group)
A point
A vector
The unit normal at the intersection point
Given a point p and vector v, find the unit normal at the first point where the ray r(t)=p+tv intersects the given shape S. If there are no intersections, returns (0,0).