add hittable list

src/hittable_list.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "hittable.h"
+
+#include <memory>
+#include <vector>
+
+class hittable_list : public hittable
+{
+    public:
+        hittable_list() {}
+        hittable_list(std::shared_ptr<hittable> object) { add(object); }
+
+        void clear() { objects_.clear(); }
+        void add (std::shared_ptr<hittable> object) { objects_.push_back(object); }
+
+        virtual bool hit(const ray& r, double t_min, double t_max,hit_record& rec) const;
+
+    private:
+        std::vector<std::shared_ptr<hittable>> objects_;
+};
+
+bool hittable_list::hit(const ray& r, double t_min, double t_max, hit_record& rec) const
+{
+    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;
+}