Ray

A ray is represented by a point in space and a direction. The ray extends from the point to infinity in the given direction. For our purposes, the direction of a ray is always assumed to be normalized:

Getting ready

We are going to declare a new Ray structure. This new structure will consist of a Point representing the origin of the ray and a vec3 representing the direction of the ray. It is assumed that the direction vector will always be normalized. We will also implement a helper function to create a ray given two points.

How to do it…

Follow these steps to implement a 3D ray:

1. Declare the new Ray structure in Geometry3D.h:

   typedef struct Ray {
      Point origin;
      vec3 direction;
      
      inline Ray() : direction(0.0f, 0.0f, 1.0f) {}
      inline Ray(const Point& o, const vec3& d) :
          origin(o), direction(d) { 
             NormalizeDirection(); 
      }
      inline void NormalizeDirection() {
          Normalize(direction);
      }
   } Ray;

2. Declare the FromPoints helper function in Geometry3D.h...