nuclear@8: #include <assert.h>
nuclear@6: #include "rt.h"
nuclear@8: #include "erebus_impl.h"
nuclear@8: 
nuclear@28: #define MAX_ITER	6
nuclear@6: 
nuclear@17: Color ray_trace(struct erebus *ctx, const Ray &ray, int iter)
nuclear@6: {
nuclear@17: 	const Scene *scn = ctx->scn;
nuclear@17: 	if(!scn) {
nuclear@17: 		return Color(1, 0, 0);
nuclear@17: 	}
nuclear@17: 
nuclear@6: 	RayHit hit;
nuclear@6: 	if(!(scn->intersect(ray, &hit))) {
nuclear@8: 		return scn->get_env_color(ray);
nuclear@6: 	}
nuclear@6: 
nuclear@17: 	return shade(ctx, hit, iter);
nuclear@6: }
nuclear@6: 
nuclear@17: Color shade(struct erebus *ctx, const RayHit &hit, int iter)
nuclear@6: {
nuclear@8: 	assert(hit.obj->get_type() == ObjType::geom);
nuclear@17: 	int max_iter = erb_getopti(ctx, ERB_OPT_MAX_ITER);
nuclear@17: 	const Scene *scn = ctx->scn;
nuclear@8: 	const GeomObject *obj = (const GeomObject*)hit.obj;
nuclear@8: 	const Material *mtl = &obj->mtl;
nuclear@8: 	const Reflectance *brdf = obj->brdf;
nuclear@8: 	const Ray &ray = hit.world_ray;
nuclear@26: 	//bool entering = true;
nuclear@8: 
nuclear@17: 	Vector3 norm = hit.calc_normal();
nuclear@23: 	if(dot_product(ray.dir, norm) > 0.0) {
nuclear@26: 		//entering = false;
nuclear@23: 		norm = -norm;
nuclear@23: 	}
nuclear@23: 
nuclear@18: 	//return norm * 0.5 + Vector3(0.5, 0.5, 0.5);
nuclear@17: 	Vector2 texcoords = hit.calc_texcoords();
nuclear@8: 
nuclear@17: 	Color color = mtl->get_attrib_color("diffuse", texcoords.x, texcoords.y);
nuclear@28: 	Color specular = mtl->get_attrib_color("specular", texcoords.x, texcoords.y);
nuclear@28: 	Color res = mtl->get_attrib_color("emissive", texcoords.x, texcoords.y) +
nuclear@28: 		color * scn->get_env().ambient;
nuclear@28: 	float shininess = mtl->get_attrib_value("shininess");
nuclear@8: 
nuclear@8: 	Vector3 sample_dir;
nuclear@8: 	float prob = brdf->sample(norm, -hit.world_ray.dir, &sample_dir);
nuclear@28: 	if(iter < max_iter && randf() <= prob && ray.energy * prob > 0.001) {
nuclear@8: 		Ray sample_ray;
nuclear@8: 		sample_ray.origin = ray.origin + ray.dir * hit.dist;
nuclear@8: 		sample_ray.dir = sample_dir;
nuclear@28: 		sample_ray.energy = ray.energy * prob;
nuclear@8: 
nuclear@17: 		res += ray_trace(ctx, sample_ray, iter + 1) * color;
nuclear@8: 	}
nuclear@8: 	return res;
nuclear@6: }