1 #include <assert.h>

2 #include "rt.h"

3 #include "erebus_impl.h"

4

5 #define MAX_ITER 8

6

7 Color ray_trace(struct erebus *ctx, const Ray &ray, int iter)

8 {

9 const Scene *scn = ctx->scn;

10 if(!scn) {

11 return Color(1, 0, 0);

12 }

13

14 RayHit hit;

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

16 return scn->get_env_color(ray);

17 }

18

19 return shade(ctx, hit, iter);

20 }

21

22 Color shade(struct erebus *ctx, const RayHit &hit, int iter)

23 {

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

25 int max_iter = erb_getopti(ctx, ERB_OPT_MAX_ITER);

26 const Scene *scn = ctx->scn;

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

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

29 const Reflectance *brdf = obj->brdf;

30 const Ray &ray = hit.world_ray;

31

32 Vector3 norm = hit.calc_normal();

33 Vector2 texcoords = hit.calc_texcoords();

34

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

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

37

38 Vector3 sample_dir;

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

40 if(iter < max_iter && randf() <= prob) {

41 Ray sample_ray;

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

43 sample_ray.dir = sample_dir;

44

45 res += ray_trace(ctx, sample_ray, iter + 1) * color;

46 }

47 return res;

48 }