Dr. Dobb's Journal - August 2008 - (Page 26)

State of the Art OPENGL AND MOBILE DEVICES: ROUND 2 continued from page 24 Listing One is a basic portable OpenGL C++ rendering framework. (The source code for the complete framework is available online; see “Resource Center,” page 5.) This is just from the header of a simple C++ class that defines the four basic things all OpenGL programs need to do: • InitializeGL is where any startup initialization code goes—load textures, create buffer objects, set initial rendering state, and so on. • ShutdownGL is just the opposite. This is where textures and other objects can be deleted. InitializeGL and ShutdownGL are always called after the OpenGL rendering context is created, and before it is destroyed, respectively. • ResizeGL is called at least once, and in windowed systems when the window changes size so that the viewport and projections can be reset as needed. • PaintGL is called to perform the OpenGL rendering. This simple framework keeps portable OpenGL and C++ code far away from system internals, Objective C, and Cocoa. I’ve used this to move code easily from not only OS to Listing One class MyGLView { public: MyGLView(void); void ResizeGL(int nWidth, int nHeight); void InitializeGL(void); void ShutdownGL(void); void PaintGL(void); }; OS, but between different application frameworks—Carbon, Cocoa, and Qt on the Mac, and low-level C/C++ SDK code, MFC, Qt, WxWidgets, GLUT, SDL, on Windows and others. The trick is to know where in the calling framework to create the class, and call these four member functions. For this article, I ported from my book The OpenGL SuperBible an example program that loads and displays a model of a ThuderBird (thanks to Ed Womack for providing the model). This example, running on an iPod Touch in Figure 2, uses Vertex Buffer objects and indexed triangles. In the book, I used a cube map to make the cockpit glass look glassy. Alas, the one compromise I had to make for the iPhone is that cube maps are not supported by OpenGL ES 1.1. In the XCode-generated project, a Cocoa class EAGLView (derived from UIView) sets up the OpenGL context and does all the dirty work. It is straightforward to then wire in this class. The first step is to rename all the .m files in the project to Download a proven, cross-platform database alternative • Unmatched performance in enterprise systems, desktop deployments, and embedded devices for over 25 years. • Simplified framework for rapid development of data-driven applications including graphical tools to speed your development and monitor critical metrics of the database engine. • Free development and free deployment in non-commercial environments. • Flexibility to use ISAM and SQL API’s within the same application. • Sophisticated feature set including 64-bit support, memory files, ADO.NET, LINQ, C#, VCL, and dbExpress. • Cross Platform support including Windows, UNIX, Linux, Mac OS X, and more. • OEM Database Engine simplifies your deployment with a single executable and flexible licensing options. Prove it to yourself in six minutes. 26 Download today! www.faircom.com Dr. Dobb’s Journal l www.ddj.com l August 2008 http://www.faircom.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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