1 #include <assert.h>

2 #include "rt.h"

3 #include "erebus_impl.h"

4

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

6 {

7 const Scene *scn = ctx->scn;

8 if(!scn) {

9 return Color(1, 0, 0);

10 }

11

12 RayHit hit;

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

14 return scn->get_env_color(ray);

15 }

16

17 return shade(ctx, hit, iter);

18 }

19

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

21 {

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

23 int max_iter = erb_getopti(ctx, ERB_OPT_MAX_ITER);

24 const Scene *scn = ctx->scn;

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

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

27 const Reflectance *brdf = obj->brdf;

28 const Ray &ray = hit.world_ray;

29 //bool entering = true;

30

31 Vector3 norm = hit.calc_normal();

32 if(dot_product(ray.dir, norm) > 0.0) {

33 //entering = false;

34 norm = -norm;

35 }

36

37 //return norm * 0.5 + Vector3(0.5, 0.5, 0.5);

38 Vector2 texcoords = hit.calc_texcoords();

39

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

41 Color specular = mtl->get_attrib_color("specular", texcoords.x, texcoords.y);

42 Color res = mtl->get_attrib_color("emissive", texcoords.x, texcoords.y) +

43 color * scn->get_env().ambient;

44 float shininess = mtl->get_attrib_value("shininess");

45

46 Vector3 sample_dir;

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

48 if(iter < max_iter && randf() <= prob && ray.energy * prob > 0.001) {

49 Ray sample_ray;

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

51 sample_ray.dir = sample_dir;

52 sample_ray.energy = ray.energy * prob;

53

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

55 }

56

57 res.w = 1.0;

58 return res;

59 }