hittable_list.h

#ifndef HITTABLE_LIST_H
#define HITTABLE_LIST_H

#include <memory>
#include <vector>
#include "hittable.h"

struct hittable_list : public hittable {
    hittable_list() {}
    hittable_list(std::shared_ptr<hittable> object) {add(object);}
    std::vector<std::shared_ptr<hittable>> objects;
    void clear() {objects.clear();}
    void add(std::shared_ptr<hittable> object) {objects.push_back(object);}
    bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const override {
        hit_record temp_rec; bool hit_anything = false; auto closest_so_far = t_max;
        for (const auto& object : objects)
            if (object->hit(r, t_min, closest_so_far, temp_rec)) {
                hit_anything = true; closest_so_far = temp_rec.t; rec = temp_rec;
            }
        return hit_anything;
    }
    bool bounding_box(double time0, double time1, aabb& output_box) const {
        if (objects.empty()) return false;
        aabb temp_box; bool first_box = true;
        for (const auto& object : objects) {
            if (!object->bounding_box(time0, time1, temp_box)) return false;
            output_box = first_box ? temp_box : surrounding_box(output_box, temp_box);
            first_box = false;
        }
        return true;
    }
    double pdf_value(const point3& o, const vec3& v) const {
        auto weight = 1.0/objects.size(), sum = 0.0;
        for (const auto& object : objects) sum += weight * object->pdf_value(o, v);
        return sum;
    }
    vec3 random(const vec3& o) const {
        auto int_size = static_cast<int>(objects.size());
        return objects[random_int(0, int_size - 1)]->random(o);
    }
};

#endif