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 "element.hh"
  12
  13
  14 namespace rt {
  15
  16
  17 /*
  18  * A class for a plane object.
  19  */
  20 class plane : public element
  21 {
  22     vec_t   norm;
  23     scal_t  dist;
  24
  25 public:
  26
  27     plane(vec_t n, scal_t d) :
  28         norm(n), dist(d)
  29     {}
  30
  31     plane(vec_t p, vec_t n) :
  32         norm(vec_normalize(n)), dist(-vec_dot(norm, p))
  33     {}
  34
  35     plane(vec_t a, vec_t b,  vec_t c) :
  36         norm(vec_normalize(vec_cross(vec_sub(b, a), vec_sub(c, a)))),
  37         dist(-vec_dot(norm, a))
  38     {}
  39
  40     virtual ~plane()
  41     {}
  42
  43     /*
  44      * Get the normal vector of the plane.
  45      */
  46     vec_t normal() const
  47     {
  48         return norm;
  49     }
  50
  51     virtual bool intersect(ray_t ray, contact_t& hit) const
  52     {
  53                 scal_t denom = vec_dot(ray.d, norm);
  54
  55                 // check for parallel condition
  56                 if (denom == S(0.0)) {
  57                         if (scal_isequal(vec_dot(ray.o, norm), -dist)) {
  58                 hit.p = ray.o;
  59                                 hit.d = S(0.0);
  60                                 hit.n = VEC_ZERO;
  61                                 return true;    // the ray lies on the plane
  62                         }
  63                         return false;       // no solution
  64                 }
  65
  66                 scal_t numer = vec_dot(ray.o, norm) + dist;
  67                 hit.d = -numer / denom;
  68                 if (hit.d < S(0.0)) {
  69             return false;
  70         }
  71
  72         hit.p = ray_solve(ray, hit.d);
  73                 if (S(0.0) <= numer) {
  74             hit.n = norm;
  75         }
  76                 else {
  77             hit.n = vec_neg(norm);
  78         }
  79                 return true;
  80     }
  81
  82     virtual vec_t txcoord(vec_t point) const
  83     {
  84         vec_t uv = VEC_ZERO;
  85
  86         point.x *= S(0.3);
  87         point.y *= S(0.3);
  88         uv.x = point.x - scal_floor(point.x);
  89         uv.y = point.z - scal_floor(point.z);
  90
  91         return uv;
  92     }
  93 };
  94
  95
  96 /*
  97  * Destroy a new'd plane, releasing its memory.
  98  */
  99 INLINE_MAYBE
 100 void plane_destroy(plane* p)
 101 {
 102     delete p;
 103 }
 104
 105
 106 } // namespace rt
 107
 108 #endif // _PLANE_HH_
 109