nuclear@4: #include <math.h>
nuclear@4: #include "bvol.h"
nuclear@4: 
nuclear@4: BSphere::BSphere()
nuclear@4: {
nuclear@4: 	radius = 1.0f;
nuclear@4: }
nuclear@4: 
nuclear@4: BSphere::BSphere(const Vector3 &c, float rad)
nuclear@4: 	: center(c)
nuclear@4: {
nuclear@4: 	radius = rad;
nuclear@4: }
nuclear@4: 
nuclear@4: void BSphere::set_center(const Vector3 &center)
nuclear@4: {
nuclear@4: 	this->center = center;
nuclear@4: }
nuclear@4: 
nuclear@4: const Vector3 &BSphere::get_center() const
nuclear@4: {
nuclear@4: 	return center;
nuclear@4: }
nuclear@4: 
nuclear@4: void BSphere::set_radius(float rad)
nuclear@4: {
nuclear@4: 	radius = rad;
nuclear@4: }
nuclear@4: 
nuclear@4: float BSphere::get_radius() const
nuclear@4: {
nuclear@4: 	return radius;
nuclear@4: }
nuclear@4: 
nuclear@4: bool BSphere::intersect(const Ray &ray, HitPoint *hit) const
nuclear@4: {
nuclear@4: 	float a = dot(ray.dir, ray.dir);
nuclear@4: 	float b = 2.0 * dot(ray.dir, ray.origin - center);
nuclear@4: 	float c = dot(ray.origin, ray.origin) + dot(center, center) -
nuclear@4: 		2.0 * dot(ray.origin, center) - radius * radius;
nuclear@4: 
nuclear@4: 	float disc = b * b - 4.0f * a * c;
nuclear@4: 	if(disc < 1e-6) {
nuclear@4: 		return false;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	float sqrt_disc = sqrt(disc);
nuclear@4: 	float x1 = (-b + sqrt_disc) / (2.0f * a);
nuclear@4: 	float x2 = (-b - sqrt_disc) / (2.0f * a);
nuclear@4: 
nuclear@4: 	if(x1 < 1e-6) x1 = x2;
nuclear@4: 	if(x2 < 1e-6) x2 = x1;
nuclear@4: 
nuclear@4: 	float t = x1 < x2 ? x1 : x2;
nuclear@4: 	if(t < 1e-6) {
nuclear@4: 		return false;
nuclear@4: 	}
nuclear@4: 
nuclear@4: 	hit->t = t;
nuclear@4: 	hit->pos = ray.origin + ray.dir * t;
nuclear@4: 	return true;
nuclear@4: }