#ifndef SPHERE_H
#define SPHERE_H

#include "target.h"

class sphere: public target
{
public:
    sphere() {};
    sphere(vec3 cen, float r) : center(cen), radius(r) {};
    virtual bool hit(const ray &r, float t_min, float t_max, hit_record &rec) const;
    vec3 center;
    float radius;
};

bool sphere::hit(const ray &r, float t_min, float t_max, hit_record &rec) const
{
    vec3 oc = r.origin() - center;
    float a = dot(r.direction(), r.direction());
    float b = dot(oc, r.direction());
    float c = dot(oc, oc) - radius * radius;
    float discriminant = b * b - a * c;

    if (discriminant > 0)
    {
        float temp = (-b - sqrt(discriminant)) / a;
        if (temp < t_max && temp > t_min)
        {
            rec.t = temp;
            rec.p = r.point_at_parameter(rec.t);
            rec.normal = (rec.p - center) / radius;
            return true;
        }
        temp = (-b + sqrt(discriminant)) / a;
        if (temp < t_max && temp > t_min)
        {
            rec.t = temp;
            rec.p = r.point_at_parameter(rec.t);
            rec.normal = (rec.p - center) / radius;
            return true;
        }
    }
    return false;
}

#endif