97 lines
2.1 KiB
Markdown
97 lines
2.1 KiB
Markdown
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# 场景图系统示例 (Scene Graph Demo)
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这个示例演示了 Extra2D 引擎场景图模块的核心功能。
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## 功能演示
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### 1. Director 场景管理
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- 通过 `SceneModule` 获取 `Director`
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- 使用 `runScene()` 启动场景
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### 2. Scene 场景容器
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- 继承 `Scene` 类创建自定义场景
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- 实现 `onEnter()` 和 `onExit()` 生命周期方法
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- 在 `update()` 中处理场景级逻辑
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### 3. Node 节点层级
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- 创建自定义节点类（`PlayerNode`, `RotatingDecoration`）
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- 使用 `addChild()` 构建节点树
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- 节点变换自动继承父节点
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### 4. Component 组件系统
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- `TransformComponent`: 位置、旋转、缩放、锚点
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- `SpriteRenderer`: 2D 精灵渲染
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- `CameraComponent`: 相机投影和视图
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### 5. Transform 变换（含锚点）
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- 归一化锚点设置 `[0,1]`
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- 锚点影响旋转中心和位置参考点
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- 世界变换自动计算
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## 运行效果
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- 蓝色方块（玩家）沿圆周运动
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- 8个彩色小方块围绕中心旋转
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- 每个小方块还有自转动画
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## 构建和运行
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```bash
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# 配置（启用示例）
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xmake f -p mingw --examples=true
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# 构建
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xmake
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# 运行
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./build/examples/scene_graph_demo/scene_graph_demo.exe
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```
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## 代码结构
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```
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scene_graph_demo/
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├── main.cpp # 程序入口
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├── game_scene.h # 场景和节点类定义
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├── game_scene.cpp # 场景和节点实现
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└── xmake.lua # 构建配置
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```
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## 关键 API
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### 创建场景
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```cpp
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class GameScene : public Scene {
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public:
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void onEnter() override;
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void update(float dt) override;
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};
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auto scene = makePtr<GameScene>();
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director->runScene(scene);
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```
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### 创建节点
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```cpp
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auto node = makePtr<Node>();
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node->setPosition(100, 200);
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node->setAnchor(0.5f, 0.5f); // 中心锚点
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node->setSize(64, 64);
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scene->addChild(node);
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```
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### 添加组件
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```cpp
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auto sprite = makePtr<SpriteRenderer>();
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sprite->setColor(Color::Red);
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node->addComponent(sprite);
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```
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### 设置相机
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```cpp
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auto camera = makePtr<CameraComponent>();
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camera->setOrtho(0, 1280, 0, 720, -1, 1);
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cameraNode->addComponent(camera);
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scene->setMainCamera(camera);
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```
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