text: #pragma once
  
  #include "ray.hpp"
  
  struct hit_record
  {
      point3 p;
      vec3 normal;
      double t;
      bool front_face;
  
      inline void set_face_normal(const ray& r, const vec3& outward_normal)
      {
          front_face = dot(r.direction, outward_normal) < 0;
          normal = front_face ? outward_normal : -outward_normal;
      }
  };
  
  class hittable
  {
      public:
          virtual bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const = 0;
  };