【Cocos2d-x游戏引擎开发笔记(2)】在屏幕上渲染文字
原创文章，转载请注明出处：http://blog.csdn.net/zhy_cheng/article/details/8268814。
这篇博文主要展示在屏幕上渲染文字，先来看看最后要实现的界面：
这个界面就是在屏幕的四个角落有不同字体不同颜色的Welcome来渲染，在屏幕的中间是汉字，颜色也是随机的。
下面来看看代码是怎么样实现的。
在main.cpp中将屏幕的大小设置为
eglView->setFrameSize(800, 480);//设置界面大小
在AppDelegate.cpp的applicationDidFinishLaunching函数中
pDirector->setDisplayStats(0);
不显示FPS
在HelloWorldSecne.cpp中，将init方法中的代码注释一部分，如下：
bool HelloWorld::init(){ bool bRet = false; do { ////////////////////////////////////////////////////////////////////////// // super init first ////////////////////////////////////////////////////////////////////////// CC_BREAK_IF(! CCLayer::init()); ////////////////////////////////////////////////////////////////////////// // add your codes below... ////////////////////////////////////////////////////////////////////////// // 1. Add a menu item with "X" image, which is clicked to quit the program. // Create a "close" menu item with close icon, it's an auto release object. /*CCMenuItemImage *pCloseItem = CCMenuItemImage::create( "CloseNormal.png", "CloseSelected.png", this, menu_selector(HelloWorld::menuCloseCallback)); CC_BREAK_IF(! pCloseItem); // Place the menu item bottom-right conner. pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20)); // Create a menu with the "close" menu item, it's an auto release object. CCMenu* pMenu = CCMenu::create(pCloseItem, NULL); pMenu->setPosition(CCPointZero); CC_BREAK_IF(! pMenu); // Add the menu to HelloWorld layer as a child layer. this->addChild(pMenu, 1); // 2. Add a label shows "Hello World". // Create a label and initialize with string "Hello World". CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24); 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 - 50)); // Add the label to HelloWorld layer as a child layer. this->addChild(pLabel, 1); // 3. Add add a splash screen, show the cocos2d splash image. CCSprite* pSprite = CCSprite::create("HelloWorld.png"); CC_BREAK_IF(! pSprite); // Place the sprite on the center of the screen pSprite->setPosition(ccp(size.width/2, size.height/2)); // Add the sprite to HelloWorld layer as a child layer. this->addChild(pSprite, 0);*/ bRet = true; } while (0); return bRet;}
现在项目运行起来应该是这样的：
好了，下面开始写自己的代码
CCLabelTTF *labelWelcome0=CCLabelTTF::create("Welcome","微软雅黑",48);CCLabelTTF *labelWelcome1=CCLabelTTF::create("Welcome","宋体",48);CCLabelTTF *labelWelcome2=CCLabelTTF::create("Welcome","Consolas",48);CCLabelTTF *labelWelcome3=CCLabelTTF::create("Welcome","Bitstream Vera Sans Mono",48);
这是“Welcome”的构造，使用create方法
第一个参数是const char *，表示要渲染的文字
第二个参数是const char*，表示文字的字体
第三个参数是float，表示字体的大小
CCSize size=CCDirector::sharedDirector()->getWinSize();float width=size.width;float height=size.height;
这里使用CCDirector获取屏幕的大小。
CCSize s0=labelWelcome0->getContentSize();CCSize s1=labelWelcome1->getContentSize();CCSize s2=labelWelcome2->getContentSize();CCSize s3=labelWelcome3->getContentSize();
这里获取要渲染的文字的大小
labelWelcome0->setPosition(CCPointMake(s0.width/2,size.height-s0.height/2));labelWelcome1->setPosition(ccp(size.width-s1.width/2,size.height-s1.height/2));labelWelcome2->setPosition(CCPoint(s2.width/2,s2.height/2));labelWelcome3->setPosition(ccp(size.width-s3.width/2,s3.height/2));//labelWelcome3->setPosition(CCPointZero);
这里设置文字显示的位置，这里的CCPointMake，ccp,CCPoint都是传递两个float参数指定显示的地点，指定的是文字中心点的地点，CCPointZero是(0,,0)点。
最后将文字加到布景中：
addChild(labelWelcome0,1);addChild(labelWelcome1,1);addChild(labelWelcome2,1);addChild(labelWelcome3,1);
现在，界面如下：
接下来为文字设置随机的颜色
srand((unsigned) time(NULL));ccColor3B c0,c1,c2,c3,c4;c0.r=rand()%256;c0.g=rand()%256;c0.b=rand()%256;c1.r=rand()%256;c1.g=rand()%256;c1.b=rand()%256;c2.r=rand()%256;c2.g=rand()%256;c2.b=rand()%256;c3.r=rand()%256;c3.g=rand()%256;c3.b=rand()%256;
这里随机设置颜色，使用了C++中的随机数。接下来
labelWelcome0->setColor(c0);labelWelcome1->setColor(c1);labelWelcome2->setColor(c2);labelWelcome3->setColor(c3);
这段代码在将文字添加到布景之前设置。好了，现在的界面是下面的：
最后要添加中间的文字了，中间的文字是中文，Windows默认的字符集是GB2312，而Cocos2d-x使用的是UTF-8，所以要将我们的字符先转为UTF-8，转换方法是使用下面的函数：
char* HelloWorld::G2U(const char* gb2312) { int len = MultiByteToWideChar(CP_ACP, 0, gb2312, -1, NULL, 0); wchar_t* wstr = new wchar_t[len+1]; memset(wstr, 0, len+1); MultiByteToWideChar(CP_ACP, 0, gb2312, -1, wstr, len); len = WideCharToMultiByte(CP_UTF8, 0, wstr, -1, NULL, 0, NULL, NULL); char* str = new char[len+1]; memset(str, 0, len+1); WideCharToMultiByte(CP_UTF8, 0, wstr, -1, str, len, NULL, NULL); if(wstr) delete[] wstr; return str; }
现在可以将中间的文字显示出来了：
CCLabelTTF *labelWelcome4=CCLabelTTF::create(G2U("游戏开发的世界，我用Cocos2d-x来降服你了~！"),"Verdana",35);
最后，最后就是我们前面的效果了。
最后init方法的全部代码：
bool HelloWorld::init(){ bool bRet = false; do { ////////////////////////////////////////////////////////////////////////// // super init first ////////////////////////////////////////////////////////////////////////// CC_BREAK_IF(! CCLayer::init()); ////////////////////////////////////////////////////////////////////////// // add your codes below... ////////////////////////////////////////////////////////////////////////// // 1. Add a menu item with "X" image, which is clicked to quit the program. // Create a "close" menu item with close icon, it's an auto release object. /*CCMenuItemImage *pCloseItem = CCMenuItemImage::create( "CloseNormal.png", "CloseSelected.png", this, menu_selector(HelloWorld::menuCloseCallback)); CC_BREAK_IF(! pCloseItem); // Place the menu item bottom-right conner. pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20)); // Create a menu with the "close" menu item, it's an auto release object. CCMenu* pMenu = CCMenu::create(pCloseItem, NULL); pMenu->setPosition(CCPointZero); CC_BREAK_IF(! pMenu); // Add the menu to HelloWorld layer as a child layer. this->addChild(pMenu, 1); // 2. Add a label shows "Hello World". // Create a label and initialize with string "Hello World". CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24); 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 - 50)); // Add the label to HelloWorld layer as a child layer. this->addChild(pLabel, 1); // 3. Add add a splash screen, show the cocos2d splash image. CCSprite* pSprite = CCSprite::create("HelloWorld.png"); CC_BREAK_IF(! pSprite); // Place the sprite on the center of the screen pSprite->setPosition(ccp(size.width/2, size.height/2)); // Add the sprite to HelloWorld layer as a child layer. this->addChild(pSprite, 0);*/CCLabelTTF *labelWelcome0=CCLabelTTF::create("Welcome","微软雅黑",48);CCLabelTTF *labelWelcome1=CCLabelTTF::create("Welcome","宋体",48);CCLabelTTF *labelWelcome2=CCLabelTTF::create("Welcome","Consolas",48);CCLabelTTF *labelWelcome3=CCLabelTTF::create("Welcome","Bitstream Vera Sans Mono",48);CCLabelTTF *labelWelcome4=CCLabelTTF::create(G2U("游戏开发的世界，我用Cocos2d-x来降服你了~！"),"Verdana",35);CCSize size=CCDirector::sharedDirector()->getWinSize();float width=size.width;float height=size.height;CCSize s0=labelWelcome0->getContentSize();CCSize s1=labelWelcome1->getContentSize();CCSize s2=labelWelcome2->getContentSize();CCSize s3=labelWelcome3->getContentSize();labelWelcome0->setPosition(CCPointMake(s0.width/2,size.height-s0.height/2));labelWelcome1->setPosition(ccp(size.width-s1.width/2,size.height-s1.height/2));labelWelcome2->setPosition(CCPoint(s2.width/2,s2.height/2));labelWelcome3->setPosition(ccp(size.width-s3.width/2,s3.height/2));//labelWelcome3->setPosition(CCPointZero);srand((unsigned) time(NULL));ccColor3B c0,c1,c2,c3,c4;c0.r=rand()%256;c0.g=rand()%256;c0.b=rand()%256;c1.r=rand()%256;c1.g=rand()%256;c1.b=rand()%256;c2.r=rand()%256;c2.g=rand()%256;c2.b=rand()%256;c3.r=rand()%256;c3.g=rand()%256;c3.b=rand()%256;c4.r=rand()%256;c4.g=rand()%256;c4.b=rand()%256;labelWelcome0->setColor(c0);labelWelcome1->setColor(c1);labelWelcome2->setColor(c2);labelWelcome3->setColor(c3);labelWelcome4->setPosition(ccp(size.width/2,size.height/2));labelWelcome4->setColor(c4);addChild(labelWelcome0,1);addChild(labelWelcome1,1);addChild(labelWelcome2,1);addChild(labelWelcome3,1);addChild(labelWelcome4,1); bRet = true; } while (0); return bRet;}