hittable.h

#ifndef HITTABLE_H
#define HITTABLE_H

#include "rtweekend.h"
class material;


class hit_record {
  public:
    point3 p;
    vec3 normal; // 法线
    shared_ptr<material> mat;
    double t;  // 控制方向
    bool front_face;

    void set_face_normal(const ray& r, const vec3& outward_normal) {
        // Sets the hit record normal vector.
        // NOTE: the parameter `outward_normal` is assumed to have unit length.

        front_face = dot(r.direction(), outward_normal) < 0;
        normal = front_face ? outward_normal : -outward_normal;
    }
};

class hittable {
  public:
    virtual ~hittable() = default;
    // t 的区间[ray_tmin, ray_tmax]
    // virtual bool hit(const ray& r, double ray_tmin, double ray_tmax, hit_record& rec) const = 0;
    virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
};

#endif