cocos2d programming guide翻译（12）

导演
缓冲
信息支持cocos2d v0.99.4和更新的版本
颜色缓冲
这个默认的缓冲时RGB565.它是一个16位的缓冲器，没有alpha（应该是一种cpu架构）.为了使用RGBA8颜色换chogn，你需要创建并初始化EAGLView
EAGLView *glView = [EAGLView viewWithFrame:[window bounds]
                                                               pixelFormat:kEAGLColorFormatRGBA8];
kEAGLColorFormatRGBA8:创建一个RGBA8颜色缓冲（32位）
kEAGLColorFormatRGB565:创建一个RGB565颜色缓冲（16位）。更快的，但是没有alpha

深度缓冲
默认情况下，cocos2d不使用深度缓冲，但是你可以创建一个当你初始化EAGLView用一个16位或者24位深度缓冲
EAGLView *glView = [EAGLView viewWithFrame:[window bounds]
                                             pixelFormat:kEAGLColorFormatRGBA8
                                       depthFormat:GL_DEPTH_COMPONENT24_OES];
GL_DEPTH_COMPONENT24_OES:24位深度缓冲
GL_DEPTH_COMPONENT16_OES:16位深度缓冲
0：没有深度缓冲被创建

高资源
自从v0.99.4开始，导演可以设置颜色来呈递缓冲再高资源模型里：
// Enables High Res mode (Retina Display) on iPhone 4 and maintains low res on all other devices
if ([UIScreen instancesRespondToSelector:@selector(scale)])
      [director setContentScaleFactor:[[UIScreen mainScreen] scale]];
从v0.99.5开始，开始支持视网膜屏幕显示：
// Enables High Res mode (Retina Display) on iPhone 4 and maintains low res on all other devices
if( ! [director enableRetinaDisplay:YES] )
      CCLOG(@"Retina Display Not supported");
它是怎么工作的：
如果你有一台iphon4，显示方案是960*640

多点抽样，或者全屏Anti_Aliasing
多点抽样可以执行在所有的设备上，但是在MBX设备中表现的冲击力更剧烈
怎么使用它
不要使用CC_DIRECTOR_INIT() macro。可以用下面的例子作为一个简单的模型
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
      // Init the window
      window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

      // must be called before any other call to the director
      [CCDirector setDirectorType:kCCDirectorTypeDisplayLink];

      // before creating any layer, set the landscape mode
      CCDirector *director = [CCDirector sharedDirector];

      // landscape orientation
      [director setDeviceOrientation:kCCDeviceOrientationLandscapeLeft];

      // set FPS at 60
      [director setAnimationInterval:1.0/60];

      // Display FPS: yes
      [director setDisplayFPS:YES];

      // Create an EAGLView with a RGB8 color buffer, and a depth buffer of 24-bits
      EAGLView *glView = [EAGLView viewWithFrame:[window bounds]
               pixelFormat:kEAGLColorFormatRGBA8             // RGBA8 color buffer
               depthFormat:GL_DEPTH_COMPONENT24_OES // 24-bit depth buffer
               preserveBackbuffer:NO
               sharegroup:nil //for sharing OpenGL contexts between threads
               multiSampling:NO //YES to enable it
               numberOfSamples:0 //can be 1 - 4 if multiSampling=YES
      ];

      // attach the openglView to the director
      [director setOpenGLView:glView];

      // Enables High Res mode (Retina Display) on iPhone 4 and maintains low res on all other devices
      if( ! [director enableRetinaDisplay:YES] )
            CCLOG(@"Retina Display Not supported");

      // make the OpenGLView a child of the main window
      [window addSubview:glView];

      // make main window visible
      [window makeKeyAndVisible];

      // Default texture format for PNG/BMP/TIFF/JPEG/GIF images
      // It can be RGBA8888, RGBA4444, RGB5_A1, RGB565
      // You can change anytime.
      [CCTexture2D setDefaultAlphaPixelFormat:kCCTexture2DPixelFormat_RGBA8888];

      // create the main scene
      CCScene *scene = [...];

      // and run it!
      [director runWithScene: scene];

      return YES;
}