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

   1
   2 /*
   3  * CS5600 University of Utah
   4  * Charles McGarvey
   5  * mcgarvey@eng.utah.edu
   6  */
   7
   8 #ifndef _PLANE_HH_
   9 #define _PLANE_HH_
  10
  11 #include "color.hh"
  12 #include "element.hh"
  13
  14
  15 namespace rt {
  16
  17
  18 /*
  19  * A class for a plane object.
  20  */
  21 class plane : public element
  22 {
  23 public:
  24
  25     color_t material;
  26     vec_t   normal;
  27     scal_t  distance;
  28
  29     plane(vec_t n, scal_t d, color_t color = COLOR_WHITE) :
  30         normal(n), distance(d), material(color)
  31     {}
  32
  33     plane(vec_t p, vec_t n, color_t color = COLOR_WHITE) :
  34         normal(vec_normalize(n)), distance(-vec_dot(normal, p)), material(color)
  35     {}
  36
  37     plane(vec_t a, vec_t b,  vec_t c, color_t color = COLOR_WHITE) :
  38         normal(vec_normalize(vec_cross(vec_sub(b, a), vec_sub(c, a)))),
  39         distance(-vec_dot(normal, a)), material(color)
  40     {}
  41
  42     virtual ~plane()
  43     {}
  44
  45     virtual bool intersect(ray_t ray, contact_t& hit) const
  46     {
  47                 // solve: [(ray.point + t*ray.direction) dot normal] + d = 0
  48
  49                 scal_t denom = vec_dot(ray.d, normal);
  50
  51                 // check for parallel condition
  52                 if (denom == S(0.0)) {
  53                         if (scal_isequal(vec_dot(ray.o, normal), -distance)) {
  54                 hit.p = ray.o;
  55                                 hit.d = S(0.0);
  56                                 hit.n = VEC_ZERO;
  57                                 return true;    // the ray lies on the plane
  58                         }
  59                         return false;       // no solution
  60                 }
  61
  62                 scal_t numer = vec_dot(ray.o, normal) + distance;
  63                 hit.d = -numer / denom;
  64                 if (hit.d < S(0.0)) {
  65             return false;
  66         }
  67
  68         hit.p = ray_solve(ray, hit.d);
  69                 if (S(0.0) <= numer) {
  70             hit.n = normal;
  71         }
  72                 else {
  73             hit.n = vec_neg(normal);
  74         }
  75                 return true;
  76     }
  77
  78     virtual color_t color(vec_t point) const
  79     {
  80         return material;
  81     }
  82 };
  83
  84
  85 /*
  86  * Destroy a new'd plane, releasing its memory.
  87  */
  88 INLINE_MAYBE
  89 void plane_destroy(plane* p)
  90 {
  91     delete p;
  92 }
  93
  94
  95 } // namespace rt
  96
  97 #endif // _PLANE_HH_
  98