This cocos2d framework package is a wonderful framework for working with OpenGL ES within iOS. Since it focuses on high performance OpenGL ES code, for the most part cocos2d bypasses Apple’s Cocoa UIViewController hierarchy. This makes sense, since within iOS, OpenGL ES usually plays out on a single UIView, and typically in a single display orientation, so there’s usually not much to control.
However, there are occasions where the functionality provided by UIViewController can be quite useful. In particular, the following functionality is best handled by adding a UIViewController into the mix:
- Auto-rotation – in some games, or other OpenGL ES applications, it makes sense to change the orientation of the application display to match changes in the orientation of the physical device. This means that when the user flips the device from landscape to portrait mode, or back again, the application display will adjust itself accordingly. The auto-rotation works on cocos2d nodes directly and does not rotate the underlying iOS Cocoa
UIView. If you are interested in combining cocos2d nodes withUIViewsand having them auto-rotate together, please review cocos2d support for that here. - Device camera overlay – an increasingly popular use for iOS devices is to overlay a game or app view on top of the image visible through the device’s camera. This is known as augmented reality, and provides the user with a combined view of the real world overlaid with images generated by the application. For this use, a
UIViewControlleris mandatory, since it controls the merging of the real-world and generated image streams.
Here at The Brenwill Workshop, some of our iOS applications actually use both of these features, and we’ve developed a small framework that can easily add the capabilities above to any cocos2d application. This article describes the design and use of this framework.
Continue reading cocos2d and UIViewControllers
