nuclear@8: #include <assert.h>
nuclear@6: #include "rt.h"
nuclear@8: #include "erebus_impl.h"
nuclear@8: 
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@43: 	if(iter > erb_getopti(ctx, ERB_OPT_MAX_ITER) || ray.energy < 0.0001) {
nuclear@43: 		//return Color(1, 0, 1);
nuclear@43: 		return Color(0, 0, 0);
nuclear@43: 	}
nuclear@43: 
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: 	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@43: 	Vector3 pos = ray.origin + ray.dir * hit.dist;
nuclear@43: 
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@43: 	Color res = color * scn->get_env().ambient;
nuclear@28: 	float shininess = mtl->get_attrib_value("shininess");
nuclear@8: 
nuclear@43: 	res += mtl->get_attrib_color("emissive", texcoords.x, texcoords.y);
nuclear@43: 
nuclear@43: 	/*
nuclear@43: 	// calculate direct illumination
nuclear@43: 	Vector3 vdir = -ray.dir.normalized();
nuclear@43: 	std::list<ObjectInstance> lights = scn->gen_light_list();
nuclear@43: 	auto it = lights.cbegin();
nuclear@43: 	while(it != lights.cend()) {
nuclear@43: 		const ObjectInstance &inst = *it++;
nuclear@43: 		GeomObject *light = (GeomObject*)inst.obj;
nuclear@43: 		SceneNode *light_node = inst.node;
nuclear@43: 
nuclear@43: 		if(obj == light) {
nuclear@43: 			// don't try to get illumination from ourselves
nuclear@43: 			continue;
nuclear@43: 		}
nuclear@43: 
nuclear@43: 		const Matrix4x4 &xform = light_node->get_matrix();
nuclear@43: 		const Matrix4x4 &inv_xform = light_node->get_inv_matrix();
nuclear@43: 		Vector3 spt = light->gen_surface_point().transformed(xform);
nuclear@43: 
nuclear@43: 		Vector3 ldir = spt - pos;
nuclear@43: 		if(dot_product(ldir, norm) < 0.0) {
nuclear@43: 			continue;
nuclear@43: 		}
nuclear@43: 		Ray shadow_ray{pos, ldir};
nuclear@43: 
nuclear@43: 		RayHit shadow_hit;
nuclear@43: 		shadow_hit.obj = 0;
nuclear@43: 		if(scn->intersect(shadow_ray, &shadow_hit) && shadow_hit.obj != light &&
nuclear@43: 				shadow_hit.dist < 0.99999 && shadow_hit.dist > 1e-5) {
nuclear@43: 			// we're in shadow, skip
nuclear@43: 			continue;
nuclear@43: 		}
nuclear@43: 
nuclear@43: 		if(!shadow_hit.obj) {
nuclear@43: 			shadow_hit.obj = light;
nuclear@43: 			shadow_hit.dist = 1.0;
nuclear@43: 			shadow_hit.world_ray = shadow_ray;
nuclear@43: 			shadow_hit.local_ray = shadow_ray.transformed(inv_xform);
nuclear@43: 			shadow_hit.node = inst.node;
nuclear@43: 		}
nuclear@43: 
nuclear@43: 		Vector2 tc = shadow_hit.calc_texcoords();
nuclear@43: 		Color lcol = light->mtl.get_attrib_color("emissive", tc.x, tc.y);
nuclear@43: 
nuclear@43: 		ldir.normalize();
nuclear@43: 		norm.normalize();
nuclear@43: 		float ndotl = dot_product(ldir, norm);
nuclear@43: 
nuclear@43: 		Vector3 refl = ldir.reflection(norm);
nuclear@43: 		float vdotr = dot_product(vdir, refl);
nuclear@43: 
nuclear@43: 		Color direct = ray.energy * lcol * (color * ndotl);// + specular * pow(vdotr, shininess));
nuclear@43: 		assert(direct.x >= 0.0 && direct.y >= 0.0 && direct.z >= 0.0);
nuclear@43: 		res += direct;
nuclear@43: 	}
nuclear@43: 	*/
nuclear@43: 
nuclear@8: 	Vector3 sample_dir;
nuclear@43: 	float prob = brdf->sample(SurfaceGeometry(norm), -ray.dir, &sample_dir);
nuclear@43: 	if(randf() <= prob) {
nuclear@8: 		Ray sample_ray;
nuclear@43: 		sample_ray.origin = pos;
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@29: 
nuclear@29: 	res.w = 1.0;
nuclear@8: 	return res;
nuclear@6: }