cocos2d and UIViewControllers

By Bill Hollings, on August 10th, 2010

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 with UIViews and 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 UIViewController is 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.
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cocos2d UI Controls

By Bill Hollings, on August 8th, 2010

This cocos2d framework package includes several useful cocos2d user interface controls and frameworks, including:

  • Joystick – a flexible joystick for user control in two dimensions with a single finger
  • CCNodeAdornments – a framework for assigning adornments to CCNodes to temporarily change the appearance of the CCNode, such as scaling, fading, adding visual embellishments, etc. This is most useful when used with menu items to temporarily change the appearance of the menu item during user selection.

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Flexible iOS Logging

By Bill Hollings, on July 23rd, 2010

Apple’s Cocoa SDK framework for the iOS provides basic logging capabilities through the NSLog function. This allows the developer to log simple text messages to the development console.

However, the use of NSLog suffers from two drawbacks:

  1. There is only one level of logging with NSLog. So during development, you get a record of all of the NSLog calls that you’ve inserted, some of which might be quite detailed and frequent, and it’s easy to be overwhelmed by the clutter. There is no way of selectively turning off some of the output.
  2. The NSLog function is called every time it is encountered, including within executing production release code. To avoid this, developers must typically remove all calls to NSLog before compiling for a production release. This is a headache fraught with possible mistakes and inhibits debugging future releases.

To remedy this, we’ve developed a logging framework that solves both of these issues. This library consists of a single Logging.h header file which adds, to iOS, flexible, non-intrusive logging capabilities that are efficiently enabled or disabled via compile switches. Continue reading Flexible iOS Logging

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