Dogcows Code - chaz/rasterize/blob - sphere.hh

   1
   2 /*
   3  * CS5600 University of Utah
   4  * Charles McGarvey
   5  * mcgarvey@eng.utah.edu
   6  */
   7
   8 #ifndef _SPHERE_HH_
   9 #define _SPHERE_HH_
  10
  11 #include "element.hh"
  12
  13
  14 namespace rt {
  15
  16
  17 /*
  18  * A class for a sphere object.
  19  */
  20 class sphere : public element
  21 {
  22     vec_t   origin;
  23     scal_t  radius;
  24
  25 public:
  26
  27     sphere(vec_t o, scal_t r = S(1.0)) :
  28         origin(o), radius(r)
  29     {}
  30
  31     virtual ~sphere()
  32     {}
  33
  34     virtual bool intersect(ray_t ray, contact_t& hit) const
  35     {
  36         vec_t   b = vec_sub(origin, ray.o);
  37                 scal_t  z = vec_dot(b, ray.d);
  38
  39                 // check if the sphere is behind the ray
  40                 if (z < S(0.0)) {
  41             return false;
  42         }
  43
  44                 scal_t d2 = vec_dot(b, b) - z * z;
  45                 scal_t r2 = radius * radius;
  46
  47                 // check for an intersection
  48                 if (r2 < d2) {
  49             return false;
  50         }
  51
  52                 hit.d = z - std::sqrt(r2 - d2);
  53                 if (hit.d < S(0.0)) {
  54             return false;
  55         }
  56
  57         hit.p = ray_solve(ray, hit.d);
  58         hit.n = vec_sub(hit.p, origin);
  59                 return true;
  60     }
  61
  62     virtual vec_t txcoord(vec_t point) const
  63     {
  64         vec_t uv = VEC_ZERO;
  65
  66         scal_t theta = scal_atan2(point.z, point.x);
  67         scal_t phi = asin(point.y / radius);
  68
  69         uv.x = theta / (S(2.0) * M_PI) + S(0.5);
  70         uv.y = phi / M_PI + S(0.5);
  71
  72         return uv;
  73     }
  74 };
  75
  76
  77 /*
  78  * Destroy a new'd sphere, releasing its memory.
  79  */
  80 INLINE_MAYBE
  81 void sphere_destroy(sphere* s)
  82 {
  83     delete s;
  84 }
  85
  86
  87 } // namespace rt
  88
  89 #endif // _SPHERE_HH_
  90