scene.hpp

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// This file is part of the Rendering Engine project.
// Author: Alexander Obzherin <alexanderobzherin@gmail.com>
// Copyright (c) 2025 Alexander Obzherin
// Distributed under the terms of the zlib License. See LICENSE.md for details.
 
#pragma once
 
#include <memory>
#include <vector>
#include <string>
 
#include "rendering_engine_export.hpp"
 
namespace rendering_engine
{
class SceneManager;
class Camera;
class Camera2D;
class Drawable3D;
class Drawable2D;
 
/**
 * @class Scene
 * @brief Base class representing a renderable scene.
 *
 * A Scene acts as a container for drawable objects (2D and 3D) and defines
 * the update and draw lifecycle of a game or rendering context.
 *
 * Derived scene classes should override Initialize(), Update(), and Draw()
 * to implement specific logic and populate the drawable lists.
 *
 * @note Scenes are created and managed by SceneManager.
 * @see SceneManager, Drawable3D, Drawable2D, Camera, Camera2D
 */
class RE_API Scene
{
public:
    /**
     * @brief Constructs a Scene instance associated with a SceneManager.
     * @param sceneManager Reference to the SceneManager that owns this Scene.
     */
    Scene(SceneManager& sceneManager);
    /**
     * @brief Virtual destructor for safe polymorphic destruction.
     */
    ~Scene() = default;
    /**
     * @brief Initializes scene resources and drawables.
     *
     * Called once when the scene becomes active.
     * Derived classes should override this to load assets and create objects.
     */
    virtual void Initialize();
    /**
     * @brief Updates all objects within the scene.
     * @param deltaTime Time elapsed since the last frame (in milliseconds).
     *
     * Called once per frame. Override to implement per-frame logic such as
     * animation, physics updates, or scene transitions.
     */
    virtual void Update(float deltaTime);
    /**
     * @brief Renders all 3D and 2D drawables in the scene.
     *
     * The base implementation can iterate through mDrawables3D and mDrawables2D
     * to call each object�s Draw() method, using the active cameras.
     */
    virtual void Draw();
    /**
     * @brief Releases scene-specific resources and prepares for shutdown.
     *
     * Called when the scene is being unloaded or replaced.
     */
    virtual void Shutdown();
    /**
     * @brief Gets a reference to the SceneManager that owns this scene.
     * @return Reference to the owning SceneManager.
     */
    SceneManager& GetSceneManager();
    /**
     * @brief Requests to load another scene.
     * @param newSceneName The name of the registered scene to load next.
     *
     * This function delegates to SceneManager::LoadScene().
     */
    void LoadScene(std::string newSceneName);
 
protected:
    SceneManager& mSceneManager;
 
    std::shared_ptr<Camera>  mActiveCamera3D;
    std::shared_ptr<Camera2D> mActiveCamera2D;
 
    std::vector<Drawable3D*> mDrawables3D;
    std::vector<Drawable2D*> mDrawables2D;
};
 
} // namespace rendering_engine