Line intersection

After point containment, the line intersection the is the next logical intersection test to implement. Knowing if a line intersects one of the basic 2D primitives is very useful, and in most cases rather straightforward to implement.

Getting ready

We are going to implement functions to test if a line is intersecting any of the basic 2D primitives. To keep the naming of these functions a little more convenient, we are going to use the #define macro to create aliases for each function.

How to do it…

Follow these steps to test if a line intersects any of the two-dimensional primitives we have defined so far:

1. Declare the line test functions in Geometry2D.h:

   bool LineCircle(const Line2D& line, const Circle& circle);
   bool LineRectangle(const Line2D& l, const Rectangle2D& r);
   bool LineOrientedRectangle(const Line2D& line,
      const OrientedRectangle& rectangle);

2. Using the #define directive, add aliases for all these functions to Geometry2D.h. These defines do not...