Dr. Dobb's Journal - August 2008 - (Page 20)

State of the Art by Richard S. Wright Jr. OpenGL and Mobile Devices: Round 2 OpenGL ES for the iPhone and iPod Touch In my June 2006 Dr. Dobb’s article “OpenGL and Mobile Devices” (www.ddj.com/mobile/ Richard is a developer for Software Bisque, lead author of The OpenGL SuperBible, and a professor at Full Sail University in Winter Park Florida where he teaches OpenGL programming in the game design degree program. He can be reached at richw@fullsail.edu. 187203532), I examined OpenGL ES, a subset of OpenGL for mobile devices. Since then, the world of mobile devices has radically changed. Mobile devices with 3D graphics are readily available, as are downloadable SDKs from Sony, Nokia, and others. And then there’s Apple’s iPhone and iPod Touch. When first announced, what caught my attention was Steve Jobs saying that the iPhone was running a version of OS X. Like every other Mac developer, the first thought that ran through my mind was “I can write software for that thing.” The second thing that went through my mind was “If it’s OS X, then it has to be using OpenGL” because OpenGL,the de facto standard for cross-platform realtime 3D graphics, is an integral part of the Macintosh operating system. All we needed was an iPhone SDK. Well, the SDK is finally available and it’s a complete XCode suite—compiler and debugger, performance analysis tools, a desktop simulator, sample code, and really good documentation. Frameworks are available for all the core OS X technologies, plus iPhone/iPod Touch specific features such as a touch interface, camera, accelerometer, and (my favorite) OpenGL ES. The iPhone and iPod Touch both support OpenGL ES 1.1. Of particular interest to me are Vertex Buffer Objects, a minimum of at least one userdefined clipping plane, point sprites, some point parameters (distance attenuation), mipmapping, vertex skinning, and an extension for using a texture as a background image. This is a very capable and featurerich graphics API, and it’s 100-percent hardware accelerated. The Hardware The graphics hardware behind the iPhone and iPod Touch is a PowerVR MBX Lite, which uses Tile-Based Deferred Rendering. (Sony Ericsson uses this same chip for some of its cell phones.) In addition to Apple’s SDK, you should get the PowerVR developer’s notes that include useful performance tips (www.imgtec.com). There are a few limitations you should know from the start: 20 Dr. Dobb’s Journal l www.ddj.com l August 2008 http://www.ddj.com/mobile/187203532 http://www.ddj.com/mobile/187203532 http://www.imgtec.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - August 2008

Dr. Dobb's Journal - August 2008 Contents Friday Night Fish Fry Alia Vox Developer Diaries Developer’s Notebook A Conversation with Christos Papadimitriou OpenGL and Mobile Devices: Round 2 Ellipse Specification Using Vectors Embed Custom GUIs in WPF Building RIAs on J2EE Foundations Disentangling Concepts in Object-Oriented Systems The Agile Edge Effective Concurrency Swaine’s Flames

Dr. Dobb's Journal - August 2008

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