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In relation to this question on Using OpenGL extensions, what's the purpose of these extension functions? Why would I want to use them? Further, are there any tradeoffs or gotchas associated with using them?
In relation to this question on Using OpenGL extensions, what's the purpose of these extension functions? Why would I want to use them? Further, are there any tradeoffs or gotchas associated with using them?
OpenGL Extensions are new features added to the OpenGL specification, they are added by the OpenGL standards body and by the various graphics card vendors. These are exposed to the programmer as new function calls or variables. Every new version of the OpenGL specification ships with newer functionality and (typically) includes all the previous functionality and extensions.
The real problem with OpenGL extensions exists only on Windows. Microsoft hasn't supported any extensions that have been released after OpenGL v1.1. The graphics card vendors overcome this by shipping their own version of this functionality through header files and libraries. However, using this can be a bit painful as the question you linked to shows. But this problem has mostly gone away with the popularity of GLEW, which takes care of wrapping all this into a easy-to-use package.
If you do use a very recent OpenGL extension, be aware that it may not be supported on older graphics hardware. Other than this, there's no other disadvantage to using these extensions. Most of the extensions which become standard are pretty darn useful and there's very little logic to not use them.