自己动手写cocos2dx游戏引擎(四)——窗体GLView

上一节中我们获取到了Director对象。

通过这个对象我们可以获取到一个OpenGL的一个视图。

在定义GLview之前，我们需要定义一个常用几何头文件。

//Geometry.h

#ifndef __GEMMETRY_H__
#define __GEMMETRY_H__

class Size {
    public:
        Size() {}
        Size(float width,float height) {
            this->width = width;
            this->height = height;
        }   

        float width;
        float height;
};

class Vec2 {
    public:
        Vec2() {}
        Vec2(float x,float y) {
            this->x = x;
            this->y = y;
        }   
        float x;
        float y;
};

class Rect {
    public:
        Rect() {}
        Rect(float x,float y,float width,float height) {
            origin.x = x;
            origin.y = y;

            size.width = width;
            size.height = height;
        }   
        Vec2 origin;
        Size  size;
};

#endif

//GLView.h

#ifndef __GLVIEW_H__                                                                                                  
#define __GLVIEW_H__                                                                                                  
                                                                                                                      
#include "Geometry.h"                                                                                                 
                                                                                                                      
class GLView {                                                                                                        
    public:                                                                                                           
        virtual ~GLView() {}                                                                                          
        virtual void setViewName(const std::string& viewname) {                                                       
            _viewName = viewname;                                                                                     
        }                                                                                                             
        virtual void setFrameSize(float width,float height) {                                                        
            _designResolutionSize = _screenSize = Size(width,height);                                                
        }                                                                                                             
    protected:                                                                                                        
        std::string _viewName;                                                                                        
        Size _designResolutionSize;                                                                                   
        Size _screenSize;                                                                                             
};                                                                                                                    
                                                                                                                      
#endif

在APPDelegate中获取的并不是GLView的对象，而是它的子类对象GLViewImpl

#ifndef __GLVIEWIMPL_H__                                                                                              
#define __GLVIEWIMPL_H__                                                                                              
                                                                                                                      
#include "GLView.h"                                                                                                   
                                                                                                                      
class GLViewImpl: public GLView {                                                                                     
    public:                                                                                                           
        static GLViewImpl* createWithRect(const std::string& viewName,Rect rect);                                    
        bool initWithRect(const std::string& viewName,Rect rect);                                                    
};                                                                                                                    
                                                                                                                      
GLViewImpl* GLViewImpl::createWithRect(const std::string& viewName,Rect rect) {                                      
    GLViewImpl* ret = new GLViewImpl;                                                                                 
    if (ret && ret->initWithRect(viewName,rect)) {                                                                  
        // ret->autorelease;// 后面再看内存管理                                                                       
        return ret;                                                                                                   
    }                                                                                                                 
    if (ret != NULL) {                                                                                                
        delete ret;                                                                                                   
        ret = NULL;                                                                                                   
    }                                                                                                                 
    return NULL;                                                                                                      
}                                                                                                                     
                                                                                                                      
bool GLViewImpl::initWithRect(const std::string& viewName,Rect rect) {                                               
    setViewName(viewName);                                                                                            
    setFrameSize(rect.size.width,rect.size.height);                                                                  
}                                                                                                                     
                                                                                                                      
#endif

然后在AppDelegate中调用时，判断当前窗口是否存在，不存在就创建一个：

#ifndef __APP_DELEGATE_H__
#define __APP_DELEGATE_H__

#include "Application.h"
#include "Director.h"
#include "GLView.h"
#include "GLViewImpl.h"
#include "Geometry.h"

#include <iostream>

class AppDelegate: private Application {
    public:
        virtual bool applicationDidFinishLaunching() {
            Director* director = Director::getInstance();
            GLView* glview = director->getOpenGLView();
            if (!glview) {
                glview = GLViewImpl::createWithRect("WinName",Rect(0,960,640));
                director->setOpenGLView(glview);
            }   
            return true;
        }   
};

#endif

#ifndef __DIRECTOR_H__                                                                                                
#define __DIRECTOR_H__                                                                                                
                                                                                                                      
#include "GLView.h"                                                                                                   
                                                                                                                      
class Director {                                                                                                      
    public:                                                                                                           
        Director() {                                                                                                  
            _openGLView = NULL;                                                                                       
        }                                                                                                             
        virtual ~Director() {}                                                                                        
        static Director* getInstance();                                                                               
        GLView* getOpenGLView() { return _openGLView; }                                                               
        virtual bool init(){ return true; }                                                                           
        void setOpenGLView(GLView *openGLView) {                                                                      
            if (_openGLView != openGLView) {                                                                          
                if (_openGLView) {                                                                                    
                    // 释放已经存在的视图对象,后面再看                                                               
                }                                                                                                     
                _openGLView = openGLView;                                                                             
            }                                                                                                         
        }                                                                                                             
    private:                                                                                                          
        GLView *_openGLView;                                                                                          
};                                                                                                                    
                                                                                                                      
class DisplayLinkDirector : public Director {                                                                         
    public:                                                                                                           
                                                                                                                      
};                                                                                                                    
                                                                                                                      
static DisplayLinkDirector *s_SharedDirector = NULL;                                                                  
                                                                                                                      
Director* Director::getInstance()                                                                                     
{                                                                                                                     
    if (!s_SharedDirector) {                                                                                          
        s_SharedDirector = new DisplayLinkDirector;                                                                   
        s_SharedDirector->init();                                                                                     
    }                                                                                                                 
    return s_SharedDirector;                                                                                          
}                                                                                                                     
                                                                                                                      
#endif

实际上到这一步就启动流程已经完成，如果在cocos2dx的项目中，就可以看到一个黑色的窗口，另外还有场景和消息循环没有加进来。

附代码：demo4

（编辑：李大同）

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