1 #include <assert.h>

2 #include "rt.h"

3 #include "erebus_impl.h"

4

5 #define MAX_ITER 8

6

7 Color ray_trace(const Ray &ray, const Scene *scn, int iter)

8 {

9 RayHit hit;

10 if(!(scn->intersect(ray, &hit))) {

11 return scn->get_env_color(ray);

12 }

13

14 return shade(hit, scn, iter);

15 }

16

17 Color shade(const RayHit &hit, const Scene *scn, int iter)

18 {

19 assert(hit.obj->get_type() == ObjType::geom);

20 const GeomObject *obj = (const GeomObject*)hit.obj;

21 const Material *mtl = &obj->mtl;

22 const Reflectance *brdf = obj->brdf;

23 const Ray &ray = hit.world_ray;

24

25 Vector3 norm = obj->calc_normal(hit);

26 Vector2 texcoords = obj->calc_texcoords(hit);

27

28 Color color = mtl->get_attrib_color("albedo", texcoords.x, texcoords.y);

29 Color res = mtl->get_attrib_color("emissive") + color * scn->get_env().ambient;

30

31 Vector3 sample_dir;

32 float prob = brdf->sample(norm, -hit.world_ray.dir, &sample_dir);

33 if(iter < MAX_ITER && randf() <= prob) {

34 Ray sample_ray;

35 sample_ray.origin = ray.origin + ray.dir * hit.dist;

36 sample_ray.dir = sample_dir;

37

38 res += ray_trace(sample_ray, scn, iter + 1) * color;

39 }

40 return res;

41 }