nuclear@16: #include <math.h>
nuclear@4: #include <float.h>
nuclear@4: #include "geomobj.h"
nuclear@4: 
nuclear@4: static LambertRefl lambert;
nuclear@4: 
nuclear@4: GeomObject::GeomObject()
nuclear@4: {
nuclear@4: 	brdf = &lambert;
nuclear@4: }
nuclear@4: 
nuclear@4: ObjType GeomObject::get_type() const
nuclear@4: {
nuclear@4: 	return ObjType::geom;
nuclear@4: }
nuclear@4: 
nuclear@4: bool GeomObject::intersect(const Ray &ray, RayHit *hit) const
nuclear@4: {
nuclear@4: 	return false;
nuclear@4: }
nuclear@4: 
nuclear@8: Vector3 GeomObject::calc_normal(const RayHit &hit) const
nuclear@8: {
nuclear@8: 	// when you look at singularities, the singularities always look back at you :)
nuclear@17: 	return -(hit.local_ray.dir).normalized();
nuclear@8: }
nuclear@8: 
nuclear@8: Vector3 GeomObject::calc_tangent(const RayHit &hit) const
nuclear@8: {
nuclear@8: 	return Vector3(1, 0, 0);	// whatever...
nuclear@8: }
nuclear@8: 
nuclear@8: Vector2 GeomObject::calc_texcoords(const RayHit &hit) const
nuclear@8: {
nuclear@8: 	return Vector2();
nuclear@8: }
nuclear@8: 
nuclear@4: // --- class Sphere ---
nuclear@4: 
nuclear@4: bool Sphere::intersect(const Ray &ray, RayHit *hit) const
nuclear@4: {
nuclear@4: 	// assumes center is the origin and radius is 1
nuclear@4: 	float a = dot_product(ray.dir, ray.dir);
nuclear@4: 	float b = 2.0 * dot_product(ray.dir, ray.origin);
nuclear@4: 	float c = dot_product(ray.origin, ray.origin) - 1.0;
nuclear@4: 
nuclear@4: 	float d = b * b - 4.0 * a * c;
nuclear@17: 	if(d < 1e-6) return false;
nuclear@4: 
nuclear@4: 	float sqrt_d = sqrt(d);
nuclear@4: 	float t0 = (-b + sqrt_d) / (2.0 * a);
nuclear@4: 	float t1 = (-b - sqrt_d) / (2.0 * a);
nuclear@4: 
nuclear@17: 	if(t0 < 1e-6) t0 = t1;
nuclear@17: 	if(t1 < 1e-6) t1 = t0;
nuclear@4: 	float t = t0 < t1 ? t0 : t1;
nuclear@17: 	if(t < 1e-6) return false;
nuclear@4: 
nuclear@4: 	if(hit) {
nuclear@4: 		hit->dist = t;
nuclear@4: 		hit->obj = this;
nuclear@4: 		hit->subobj = 0;
nuclear@4: 	}
nuclear@4: 	return true;
nuclear@4: }
nuclear@4: 
nuclear@8: Vector3 Sphere::calc_normal(const RayHit &hit) const
nuclear@8: {
nuclear@17: 	Vector3 pt = hit.local_ray.origin + hit.local_ray.dir * hit.dist;
nuclear@8: 	return pt.normalized();
nuclear@8: }
nuclear@8: 
nuclear@8: static inline Vector3 sphvec(float u, float v)
nuclear@8: {
nuclear@8: 	float theta = u * M_PI * 2.0;
nuclear@8: 	float phi = v * M_PI;
nuclear@8: 
nuclear@8: 	return Vector3(sin(theta) * sin(phi), cos(phi), cos(theta) * sin(phi));
nuclear@8: }
nuclear@8: 
nuclear@8: Vector3 Sphere::calc_tangent(const RayHit &hit) const
nuclear@8: {
nuclear@8: 	Vector2 uv = calc_texcoords(hit);
nuclear@8: 	Vector3 pnext = sphvec(uv.x + 0.05, 0.5);
nuclear@8: 	Vector3 pprev = sphvec(uv.y - 0.05, 0.5);
nuclear@8: 	return (pnext - pprev).normalized();
nuclear@8: }
nuclear@8: 
nuclear@8: Vector2 Sphere::calc_texcoords(const RayHit &hit) const
nuclear@8: {
nuclear@17: 	Vector3 pt = hit.local_ray.origin + hit.local_ray.dir * hit.dist;
nuclear@8: 	pt.normalize();
nuclear@8: 
nuclear@8: 	float theta = atan2(pt.z, pt.x);
nuclear@8: 	float phi = acos(pt.y);
nuclear@8: 
nuclear@8: 	return Vector2(theta / M_PI + 0.5, phi / M_PI);
nuclear@8: }
nuclear@8: 
nuclear@8: 
nuclear@4: // --- class Box ---
nuclear@4: 
nuclear@4: bool Box::intersect(const Ray &ray, RayHit *hit) const
nuclear@4: {
nuclear@18: 	Vector3 param[2] = {Vector3{-0.5, -0.5, -0.5}, Vector3{0.5, 0.5, 0.5}};
nuclear@18: 	Vector3 inv_dir{1.0f / ray.dir.x, 1.0f / ray.dir.y, 1.0f / ray.dir.z};
nuclear@18: 	int sign[3] = {inv_dir.x < 0, inv_dir.y < 0, inv_dir.z < 0};
nuclear@18: 
nuclear@18: 	float tmin = (param[sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@18: 	float tmax = (param[1 - sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@18: 	float tymin = (param[sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@18: 	float tymax = (param[1 - sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@18: 
nuclear@18: 	if(tmin > tymax || tymin > tmax) {
nuclear@18: 		return false;
nuclear@18: 	}
nuclear@18: 	if(tymin > tmin) {
nuclear@18: 		tmin = tymin;
nuclear@18: 	}
nuclear@18: 	if(tymax < tmax) {
nuclear@18: 		tmax = tymax;
nuclear@18: 	}
nuclear@18: 
nuclear@18: 	float tzmin = (param[sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@18: 	float tzmax = (param[1 - sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@18: 
nuclear@18: 	if(tmin > tzmax || tzmin > tmax) {
nuclear@18: 		return false;
nuclear@18: 	}
nuclear@18: 	if(tzmin > tmin) {
nuclear@18: 		tmin = tzmin;
nuclear@18: 	}
nuclear@18: 	if(tzmax < tmax) {
nuclear@18: 		tmax = tzmax;
nuclear@18: 	}
nuclear@18: 
nuclear@18: 	float t = tmin < 1e-4 ? tmax : tmin;
nuclear@18: 	if(t >= 1e-4) {
nuclear@18: 		if(hit) {
nuclear@18: 			hit->obj = this;
nuclear@18: 			hit->dist = t;
nuclear@18: 		}
nuclear@18: 		return true;
nuclear@18: 	}
nuclear@4: 	return false;
nuclear@18: 
nuclear@18: }
nuclear@18: 
nuclear@18: #define BOX_EXT		0.499999
nuclear@18: Vector3 Box::calc_normal(const RayHit &hit) const
nuclear@18: {
nuclear@18: 	Vector3 pt = hit.local_ray.origin + hit.local_ray.dir * hit.dist;
nuclear@18: 	if(pt.x > BOX_EXT) return Vector3(1, 0, 0);
nuclear@18: 	if(pt.x < -BOX_EXT) return Vector3(-1, 0, 0);
nuclear@18: 	if(pt.y > BOX_EXT) return Vector3(0, 1, 0);
nuclear@18: 	if(pt.y < -BOX_EXT) return Vector3(0, -1, 0);
nuclear@18: 	if(pt.z > BOX_EXT) return Vector3(0, 0, 1);
nuclear@18: 	if(pt.z < -BOX_EXT) return Vector3(0, 0, -1);
nuclear@18: 	return Vector3(0, 0, 0);	// shouldn't happen unless numerical precision is fucked
nuclear@18: }
nuclear@18: 
nuclear@18: Vector3 Box::calc_tangent(const RayHit &hit) const
nuclear@18: {
nuclear@18: 	return Vector3(1, 0, 0);	// TODO
nuclear@18: }
nuclear@18: 
nuclear@18: Vector2 Box::calc_texcoords(const RayHit &hit) const
nuclear@18: {
nuclear@18: 	return Vector2(0, 0);	// TODO
nuclear@4: }
nuclear@4: 
nuclear@4: // --- class Triangle ---
nuclear@4: 
nuclear@4: bool Triangle::intersect(const Ray &ray, RayHit *hit) const
nuclear@4: {
nuclear@4: 	return false;
nuclear@4: }
nuclear@4: 
nuclear@4: // --- class Mesh ---
nuclear@4: 
nuclear@4: bool Mesh::intersect(const Ray &ray, RayHit *hit) const
nuclear@4: {
nuclear@4: 	RayHit nearest;
nuclear@4: 	nearest.dist = FLT_MAX;
nuclear@4: 
nuclear@4: 	for(size_t i=0; i<faces.size(); i++) {
nuclear@4: 		if(faces[i].intersect(ray, hit)) {
nuclear@4: 			if(!hit) return true;
nuclear@4: 			if(hit->dist < nearest.dist) {
nuclear@4: 				nearest = *hit;
nuclear@4: 			}
nuclear@4: 		}
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	if(nearest.dist < FLT_MAX) {
nuclear@4: 		*hit = nearest;
nuclear@4: 		hit->subobj = hit->obj;
nuclear@4: 		hit->obj = this;
nuclear@4: 		return true;
nuclear@4: 	}
nuclear@4: 	return false;
nuclear@4: }