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 "raster.hh"
  15 #include "ray.hh"
  16 #include "scene.hh"
  17
  18
  19 namespace rt {
  20
  21
  22 /*
  23  * A base class for an object in a scene.
  24  */
  25 class element
  26 {
  27     color_t     kd;
  28     raster_t*   tx;
  29
  30 public:
  31
  32     element() :
  33         kd(COLOR_WHITE), tx(NULL)
  34     {}
  35
  36     virtual ~element()
  37     {}
  38
  39     /*
  40      * Determine if a ray intersects this element.
  41      */
  42     virtual bool intersect(ray_t ray, contact_t& hit) const = 0;
  43
  44     /*
  45      * Get the material color of the element at a surface point.
  46      */
  47     virtual color_t color(vec_t point) const
  48     {
  49         return kd;
  50     }
  51
  52     /*
  53      * Get texture-coordinates from a surface point.
  54      */
  55     virtual vec_t txcoord(vec_t point) const
  56     {
  57         return VEC_ZERO;
  58     }
  59
  60     /*
  61      * Cast a ray to this element, returning the correct color value.
  62      */
  63     color_t cast(const contact_t& hit, const scene_t* scene) const
  64     {
  65         color_t kd = txcolor(hit.p);
  66         color_t Ia = color_mult(scene_ambient(scene), kd);
  67         color_t Id = diffuse(kd, hit, scene);
  68         return color_clamp(color_add(Ia, Id));
  69     }
  70
  71     /*
  72      * Get whether or not a particular surface point is shadowed by other
  73      * objects for a given light source.
  74      */
  75     bool is_shadowed(const contact_t& hit, const scene_t* scene, const light_t* light) const
  76     {
  77 #if SHADOWS
  78         ray_t ray = ray_normalize(ray_new(hit.p, vec_sub(light->v, hit.p)));
  79         for (list_t* i = scene_elements(scene); i; i = i->link) {
  80             rt::element*    obj = (rt::element*)i->val;
  81             contact_t       hit;
  82             if (this != obj && obj->intersect(ray, hit)) {
  83                 return true;
  84             }
  85         }
  86 #endif
  87
  88         return false;
  89     }
  90
  91     /*
  92      * Get the color of the element at a surface point after diffuse
  93      * lighting.
  94      */
  95     color_t diffuse(color_t kd, const contact_t& hit, const scene_t* scene) const
  96     {
  97         vec_t   n = vec_normalize(hit.n);
  98
  99         color_t c = COLOR_BLACK;
 100
 101         for (list_t* i = scene_lights(scene); i; i = i->link) {
 102             light_t* l = (light_t*)i->val;
 103             if (!is_shadowed(hit, scene, l)) {
 104                 vec_t I = vec_normalize(vec_sub(l->v, hit.p));
 105                 scal_t  dot = scal_max(vec_dot(I, n), S(0.0));
 106                 color_t Id = color_scale2(kd, l->d, dot);
 107                 c = color_add(c, Id);
 108             }
 109         }
 110
 111         return c;
 112     }
 113
 114     color_t txcolor(vec_t point) const
 115     {
 116 #if TEXTURING
 117         if (tx != NULL) {
 118             vec_t uv = txcoord(point);
 119 #if QUIRKS
 120             return raster_uv(tx, uv);
 121 #else
 122             return color_mult(color(point), raster_uv(tx, uv));
 123 #endif
 124         }
 125 #endif
 126         return color(point);
 127     }
 128
 129     void material(color_t color)
 130     {
 131         kd = color;
 132     }
 133
 134     void texture(raster_t* texture)
 135     {
 136         tx = texture;
 137     }
 138 };
 139
 140
 141 } // namespace rt
 142
 143 #endif // _ELEMENT_HH_
 144