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

   1
   2 /*
   3  * CS5600 University of Utah
   4  * Charles McGarvey
   5  * mcgarvey@eng.utah.edu
   6  */
   7
   8 #ifndef _ELEMENT_HH_
   9 #define _ELEMENT_HH_
  10
  11 #include "color.hh"
  12 #include "contact.hh"
  13 #include "light.hh"
  14 #include "ray.hh"
  15 #include "scene.hh"
  16
  17
  18 namespace rt {
  19
  20
  21 /*
  22  * A base class for an object in a scene.
  23  */
  24 class element
  25 {
  26 public:
  27
  28     virtual ~element()
  29     {}
  30
  31     /*
  32      * Determine if a ray intersects this element.
  33      */
  34     virtual bool intersect(ray_t ray, contact_t& hit) const = 0;
  35
  36     /*
  37      * Get the material color of the element at a surface point.
  38      */
  39     virtual color_t color(vec_t point) const
  40     {
  41         return COLOR_WHITE;
  42     }
  43
  44     /*
  45      * Cast a ray to this element, returning the correct color value.
  46      */
  47     color_t cast(const contact_t& hit, const scene_t* scene) const
  48     {
  49         color_t Ia = color_mult(scene_ambient(scene), color(hit.p));
  50         color_t Id = diffuse(hit, scene);
  51         return color_clamp(color_add(Ia, Id));
  52     }
  53
  54     /*
  55      * Get whether or not a particular surface point is shadowed by other
  56      * objects for a given light source.
  57      */
  58     bool is_shadowed(const contact_t& hit, const scene_t* scene, const light_t* light) const
  59     {
  60 #if SHADOWS
  61         ray_t ray = ray_normalize(ray_new(hit.p, vec_sub(light->v, hit.p)));
  62         for (list_t* i = scene_elements(scene); i; i = i->link) {
  63             rt::element*    obj = (rt::element*)i->val;
  64             contact_t       hit;
  65             if (this != obj && obj->intersect(ray, hit)) {
  66                 return true;
  67             }
  68         }
  69 #endif
  70
  71         return false;
  72     }
  73
  74     /*
  75      * Get the color of the element at a surface point after diffuse
  76      * lighting.
  77      */
  78     color_t diffuse(const contact_t& hit, const scene_t* scene) const
  79     {
  80         color_t kd = color(hit.p);
  81         vec_t   n = vec_normalize(hit.n);
  82
  83         color_t c = COLOR_BLACK;
  84
  85         for (list_t* i = scene_lights(scene); i; i = i->link) {
  86             light_t* l = (light_t*)i->val;
  87             if (!is_shadowed(hit, scene, l)) {
  88                 vec_t I = vec_normalize(vec_sub(l->v, hit.p));
  89                 scal_t  dot = scal_max(vec_dot(I, n), S(0.0));
  90                 color_t Id = color_scale2(kd, l->d, dot);
  91                 c = color_add(c, Id);
  92             }
  93         }
  94
  95         return c;
  96     }
  97 };
  98
  99
 100 } // namespace rt
 101
 102 #endif // _ELEMENT_HH_
 103