cocos2d-x初学习

1：字符串绘制
cocos2dx的字符串绘制使用的是Label，cocos2dx并不直接支持在屏幕中绘制字符串（这是有道理的，因为我们不能直接把一个string做成一个节点，那样很难理解），如果要直接绘制的话，可以自己封装opengl函数（网上有很多例子，一般是用texture做）。

其实最简单的绘制例子就是最开始的那个Helloworld。核心代码如下：

// Create a label and initialize with string "Hello World". 
CCLabelTTF* pLabel = CCLabelTTF::labelWithString("Hello World", "Thonburi", 64); 
CC_BREAK_IF(! pLabel); 
 
// Get window size and place the label upper. 
CCSize size = CCDirector::sharedDirector()->getWinSize(); 
pLabel->setPosition(ccp(size.width / 2, size.height - 20)); 
 
// Add the label to HelloWorld layer as a child layer. 
this->addChild(pLabel, 1); 

2：Menu绘制

CCMenuItemImage *pCloseItem = CCMenuItemImage::itemFromNormalImage(
										"CloseNormal.png",
										"CloseSelected.png",
										this,							menu_selector(HelloWorld::menuCloseCallback) );
pCloseItem->setPosition( ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20) );
CCMenu* eMenu = CCMenu::menuWithItems(pCloseItem,NULL);
eMenu->setPosition( CCPointZero );
this->addChild(eMenu);

CCMenuItem* newGameItem=CCMenuItemFont::itemFromString("1234", this, NULL);
CCMenuItem* startGameItem=CCMenuItemFont::itemFromString("start Game",this,NULL);
CCMenuItemToggle* itemToggle=CCMenuItemToggle::itemWithTarget(this, NULL,CCMenuItemFont::itemFromString("开"));
CCMenu* pMenu=CCMenu::menuWithItems(newGameItem,startGameItem,itemToggle,NULL);
pMenu->alignItemsVertically();
this->addChild(pMenu, 1);

3：绘制图片
cocos2dx中并没有直接绘制图片的概念，我们一般是使用CCSprite。核心代码如下：

//Add add a splash screen, show the cocos2d splash image. 
CCSprite* pSprite = CCSprite::spriteWithFile("HelloWorld.png"); 
CC_BREAK_IF(! pSprite); 
 
// Place the sprite on the center of the screen 
pSprite->setFlipX(true); //可以手动设置图形旋转和镜像，而不是使用Action，因为有许多Action是个过程，而不是直接显示结果 
pSprite->setRotation(90); 
pSprite->setPosition(ccp(size.width/2, size.height/2)); 
 
// Add the sprite to HelloWorld layer as a child layer. 
this->addChild(pSprite, 0); 

4：基本图形绘制
cocos2dx封装了大量opengl函数，用于快速绘制基本图形，这些代码的例子在，tests\DrawPrimitivesTest目录下

注意，该方法是重载node的draw方法实现的，在智能机上，并不推荐直接绘制几何图形，因为大量的坐标编码会极大降低工作效率，应尽量使用Image。而且cocos2dx的渲染机制会造成前后遮挡问题，尤其是几何图形与图片等其他node混合绘制时。

void DrawPrimitivesTest::draw() 
{ 
        CCLayer::draw(); 
 
    CCSize s = CCDirector::sharedDirector()->getWinSize(); 
         
        // draw a simple line 
        // The default state is: 
        // Line Width: 1 
        // color: 255,255,255,255 (white, non-transparent) 
        // Anti-Aliased 
        glEnable(GL_LINE_SMOOTH); 
        ccDrawLine( CCPointMake(0, 0), CCPointMake(s.width, s.height) ); 
         
        // line: color, width, aliased 
        // glLineWidth > 1 and GL_LINE_SMOOTH are not compatible 
          //注意：线宽>1 则不支持GL_LINE_SMOOTH 
        // GL_SMOOTH_LINE_WIDTH_RANGE = (1,1) on iPhone 
        glDisable(GL_LINE_SMOOTH); 
        glLineWidth( 5.0f ); 
        /*glColor4ub(255,0,0,255);*/ 
        glColor4f(1.0, 0.0, 0.0, 1.0); 
        ccDrawLine( CCPointMake(0, s.height), CCPointMake(s.width, 0) ); 
 
        // TIP: 
        // If you are going to use always the same color or width, you don't 
        // need to call it before every draw 
        // 
        // Remember: OpenGL is a state-machine. 
         
        // draw big point in the center 
        // 注意：cocos2dx绘制的是方块点 
        glPointSize(64); 
        /*glColor4ub(0,0,255,128);*/ 
        glColor4f(0.0, 0.0, 1.0, 0.5); 
        ccDrawPoint( CCPointMake(s.width / 2, s.height / 2) ); 
         
        // draw 4 small points 
        // 注意：cocos2dx绘制的是方块点 
        CCPoint points[] = { CCPointMake(60,60), CCPointMake(70,70), CCPointMake(60,70), CCPointMake(70,60) }; 
        glPointSize(4); 
        /*glColor4ub(0,255,255,255);*/ 
        glColor4f(0.0, 1.0, 1.0, 1.0); 
        ccDrawPoints( points, 4); 
         
        // draw a green circle with 10 segments 
        glLineWidth(16); 
        /*glColor4ub(0, 255, 0, 255);*/ 
        glColor4f(0.0, 1.0, 0.0, 1.0); 
        //参数依次是：中心点，半径，角度，分段数，是否连接中心点 
        ccDrawCircle( CCPointMake(s.width/2,  s.height/2), 100, 0, 10, false); 
 
        // draw a green circle with 50 segments with line to center 
        glLineWidth(2); 
        /*glColor4ub(0, 255, 255, 255);*/ 
        glColor4f(0.0, 1.0, 1.0, 1.0); 
        ccDrawCircle( CCPointMake(s.width/2, s.height/2), 50, CC_DEGREES_TO_RADIANS(90), 50, true);   
         
        // open yellow poly 
        /*glColor4ub(255, 255, 0, 255);*/ 
        glColor4f(1.0, 1.0, 0.0, 1.0); 
        glLineWidth(10); 
        CCPoint vertices[] = { CCPointMake(0,0), CCPointMake(50,50), CCPointMake(100,50), CCPointMake(100,100), CCPointMake(50,100) }; 
        //参数依次是：点数组，点数量，是否封闭 
        ccDrawPoly( vertices, 5, false); 
         
        // closed purple poly 
        /*glColor4ub(255, 0, 255, 255);*/ 
        glColor4f(1.0, 0.0, 1.0, 1.0); 
        glLineWidth(2); 
        CCPoint vertices2[] = { CCPointMake(30,130), CCPointMake(30,230), CCPointMake(50,200) }; 
        ccDrawPoly( vertices2, 3, true); 
         
        // draw quad bezier path 
          //绘制有一个控制点的贝塞尔曲线 
        ccDrawQuadBezier(CCPointMake(0,s.height), CCPointMake(s.width/2,s.height/2), CCPointMake(s.width,s.height), 50); 
 
        // draw cubic bezier path 
          //绘制有两个控制点的贝塞尔曲线 
        ccDrawCubicBezier(CCPointMake(s.width/2, s.height/2), CCPointMake(s.width/2+30,s.height/2+50), CCPointMake(s.width/2+60,s.height/2-50),CCPointMake(s.width, s.height/2),100); 
 
        //恢复opengl的正常参数 
        // restore original values 
        glLineWidth(1); 
        /*glColor4ub(255,255,255,255);*/ 
        glColor4f(1.0, 1.0, 1.0, 1.0); 
        glPointSize(1); 
} 

参考资料：
http://4137613.blog.51cto.com/4127613/754729