OpenGL笔记之事件驱动设计将相机控制类和应用程序类分离

OpenGL笔记之事件驱动设计将相机控制类和应用程序类分离

—— 2024-10-02 下午

bilibili赵新政老师的教程看后笔记

code review!

1.代码图片

运行

Mouse button 1 pressed at (100, 200)
Mouse dragged by (50, 50)
Key pressed: 65
Updating camera control

2.分析

类图:

上面的类图展示了代码中主要类的结构和关系:

• Application 类包含一个 CameraControl 指针和事件回调函数指针,通过 setMouseCallback 和 setKeyCallback 设置事件回调。
• CameraControl 是一个抽象基类,定义了处理鼠标事件、键盘事件和更新的接口。
• SimpleCameraControl 继承自 CameraControl,实现了具体的事件处理逻辑。
• MouseEvent 和 KeyEvent 分别表示鼠标事件和键盘事件的数据结构。

事件处理流程图:

事件处理流程如下:

1. 应用程序触发鼠标或键盘事件
2. 事件通过 Application::triggerMouseEvent 或 Application::triggerKeyEvent 分发到对应的全局回调函数
3. 回调函数 onMouseEvent 或 onKeyEvent 调用 SimpleCameraControl 的对应事件处理函数
4. SimpleCameraControl 的事件处理函数根据事件数据进行相应的处理

主程序流程图:

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主程序的流程如下:

1. 创建 Application 对象
2. 设置鼠标回调函数为 onMouseEvent
3. 设置键盘回调函数为 onKeyEvent
4. 调用 Application::run
   • 模拟触发鼠标事件
   • 模拟触发键盘事件
   • 调用 CameraControl::update 更新相机状态

3.UML

+------------------+
|  CameraControl   |  <<abstract>>
+------------------+
| +handleMouseEvent(MouseEvent) : void |
| +handleKeyEvent(KeyEvent) : void     |
| +update() : void                     |
+------------------+

        ^
        |
        |
+----------------------+
| SimpleCameraControl  |
+----------------------+
| -mousePressed : bool |
| -lastX : double      |
| -lastY : double      |
| -keys : map<int, bool> |
+----------------------+
| +handleMouseEvent(MouseEvent) : void |
| +handleKeyEvent(KeyEvent) : void     |
| +update() : void                     |
+----------------------+

+-------------------+
|    Application    |
+-------------------+
| -cameraControl : SimpleCameraControl*
| -mouseCallback : MouseCallback       |
| -keyCallback : KeyCallback           |
+-------------------+
| +setMouseCallback(MouseCallback) : void |
| +setKeyCallback(KeyCallback) : void     |
| +triggerMouseEvent(MouseEvent) : void   |
| +triggerKeyEvent(KeyEvent) : void       |
| +run() : void                           |
+-------------------+

+-------------------+
|    MouseEvent     |
+-------------------+
| +x : int          |
| +y : int          |
| +button : int     |
| +pressed : bool   |
+-------------------+

+-----------------+
|    KeyEvent     |
+-----------------+
| +key : int      |
+-----------------+

+--------------------+
|   Global Functions |
+--------------------+
| +onMouseEvent(MouseEvent) : void |
| +onKeyEvent(KeyEvent) : void     |
+--------------------+

4.代码

#include <iostream>
#include <map>

// 定义事件类型
enum class EventType {
    
    
    MouseClick,
    KeyPress
};

// 定义鼠标事件信息
struct MouseEvent {
    
    
    int x, y;
    int button;
    bool pressed;
};

// 定义键盘事件信息
struct KeyEvent {
    
    
    int key;
};

// 事件回调函数指针类型
using MouseCallback = void (*)(const MouseEvent&);
using KeyCallback = void (*)(const KeyEvent&);

// 抽象相机控制器基类
class CameraControl {
    
    
public:
    virtual void handleMouseEvent(const MouseEvent& event) = 0;
    virtual void handleKeyEvent(const KeyEvent& event) = 0;
    virtual void update() = 0;
};

// 一个简单的相机控制器实现
class SimpleCameraControl : public CameraControl {
    
    
public:
    void handleMouseEvent(const MouseEvent& event) override {
    
    
        if (event.pressed) {
    
    
            mousePressed = true;
            lastX = event.x;
            lastY = event.y;
            std::cout << "Mouse button " << event.button << " pressed at ("
                      << event.x << ", " << event.y << ")\n";
        } else {
    
    
            mousePressed = false;
            double deltaX = event.x - lastX;
            double deltaY = event.y - lastY;
            std::cout << "Mouse dragged by (" << deltaX << ", " << deltaY << ")\n";
            lastX = event.x;
            lastY = event.y;
        }
    }

    void handleKeyEvent(const KeyEvent& event) override {
    
    
        keys[event.key] = true;
        std::cout << "Key pressed: " << event.key << "\n";
    }

    void update() override {
    
    
        std::cout << "Updating camera control\n";
    }

private:
    bool mousePressed = false;
    double lastX = 0.0, lastY = 0.0;
    std::map<int, bool> keys;
};

// 应用程序类
class Application {
    
    
public:
    Application()
        : cameraControl(new SimpleCameraControl()) {
    
    }

    void setMouseCallback(MouseCallback callback) {
    
    
        mouseCallback = callback;
    }

    void setKeyCallback(KeyCallback callback) {
    
    
        keyCallback = callback;
    }

    void triggerMouseEvent(const MouseEvent& event) {
    
    
        if (mouseCallback) {
    
    
            mouseCallback(event);
        }
    }

    void triggerKeyEvent(const KeyEvent& event) {
    
    
        if (keyCallback) {
    
    
            keyCallback(event);
        }
    }

    void run() {
    
    
        // 模拟事件触发
        triggerMouseEvent(MouseEvent{
    
    100, 200, 1, true});
        triggerMouseEvent(MouseEvent{
    
    150, 250, 1, false});
        triggerKeyEvent(KeyEvent{
    
    65});

        // 更新相机控制
        cameraControl->update();
    }

private:
    SimpleCameraControl* cameraControl;
    MouseCallback mouseCallback = nullptr;
    KeyCallback keyCallback = nullptr;
};

// 全局函数
void onMouseEvent(const MouseEvent& event) {
    
    
    static SimpleCameraControl control;
    control.handleMouseEvent(event);
}

void onKeyEvent(const KeyEvent& event) {
    
    
    static SimpleCameraControl control;
    control.handleKeyEvent(event);
}

int main() {
    
    
    Application app;
    app.setMouseCallback(onMouseEvent);
    app.setKeyCallback(onKeyEvent);
    app.run();
    return 0;
}