Does anyone have experience writing professional OpenGL games on Windows? For the Mac, due to apple's control, the OS seems quite "uniform". For windows, due to different hardware, different drivers installed, etc ... the hardware base seems to have many many different configurations.
In theory, OpenGL provides a API that abstracts all this away. In practice, many drivers are often buggy and have weird cases -- has this been a problem for developing games on Windows?
Thanks!
I haven't yet made a professional OpenGL game on Windows, but I think one important thing is to query the OpenGL drivers about what capabilities (extensions) are available and handle those functions. There is also a package to handle this in a platform independent way with the GLEW library. Think that is a good start to understand how to handle different OpenGL capabilities.
The OpenGL Extension Wrangler Library (GLEW) is a cross-platform open-source C/C++ extension loading library. GLEW provides efficient run-time mechanisms for determining which OpenGL extensions are supported on the target platform. OpenGL core and extension functionality is exposed in a single header file. GLEW has been tested on a variety of operating systems, including Windows, Linux, Mac OS X, FreeBSD, Irix, and Solaris.
The biggest problem you will face is simply this: Windows 7 does not ship with a hardware OpenGL. If the user does not take the action to replace the default video drivers with updated versions from the vendors site the only OpenGL support they have will be a ~v1.0 software renderer.
The two biggest GPU vendors (Nvidia and ATI) both provide OpenGL 3.x drivers, which take advantage of the latest features of modern hardware. As Chris points out, the main issue is that the user will need to install the latest drivers from the vendors themselves, as Windows ships with the most rudimentary OpenGL support (thanks to Microsoft, who seem to do everything they can to knife OpenGL and push DirectX). So provided they have recent drivers, you should be fine.
There are inevitably some (mostly minor) differences between the drivers. For example, I've noticed Nvidia's GLSL compiler is a little more picky than ATI's, and rejects some shader code that otherwise works fine. Bottom line is you need to test on both (which you would be doing anyway).
The gDebugger tool seems to be pretty good at tracking down performance issues. (The OpenGL tools that ship free with Xcode are pretty awesome though.)
You'll need to get glext.h from the OpenGL extensions registry and figure out the base requirements for your app. You probably don't want to have alternate code paths based on which extensions are available, if you can help it! And as epatel mentions, there are a few libraries (such as GLEW and GLEE) which help with the process of extension management. I ended up writing my own, as I didn't like those implementations.
There's lots of engines and scene graphs for OpenGL, if you haven't already chosen your toolset.
I've found a few little bugs along the way, but nearly all were easy to work around. These days things are pretty good.