sphere.h

#ifndef SPHERE_H
#define SPERE_H

#include"hittable.h"
#include"vec3.h"

class sphere:public hittable{
    public:
        sphere(){}
        sphere(point3 cen,double r,shared_ptr<material> m)
		    :center(cen),radius(r),mat_ptr(m) {};

        virtual bool hit(const ray&r,double t_min,double t_max,hit_record& rec) const override;

        public:
          point3 center;
          double radius;   
		  shared_ptr<material> mat_ptr;
};

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

    auto discriminant = half_b*half_b - a*c;
if (discriminant > 0) {
		double root = sqrt(discriminant);
		double t = (-half_b - root) / a;
		if (t > t_min&& t < t_max) {
			rec.t = t;
			rec.p = r.at(t);
			vec3 outward_normal = (rec.p - center) / radius;
			rec.set_face_normal(r, outward_normal);
			rec.mat_ptr = mat_ptr;
			
			return true;
		}
		t = (-half_b + root) / a;
		if (t > t_min&& t < t_max) {
			rec.t = t;
			rec.p = r.at(t);
			vec3 outward_normal = (rec.p - center) / radius;
			rec.set_face_normal(r, outward_normal);
			rec.mat_ptr = mat_ptr;

			return true;
		}
	}
	return false;
}


#endif