All posts tagged with "Nicholas needs more death gems to complete the summoning"

A Crash Course in Moving A Legacy OpenGL Codebase to Core OpenGL 3.2

I’m actually absconding from┬áthe usual subject of these blogposts this week to do technical writing which people might find useful – mainly because a lot of the information on this seems to be scattered all over the Internet. One of the issues with our Mac port of Clockwork Empires which has prevented it from launching when we wanted to is that we discovered – a bit late in our schedule – that we couldn’t fix all of the shader issues on OS X without porting the entire game from what we were using (OpenGL’s “compatibility” mode plus a ton of extensions, dating back to when this codebase was started ages and ages ago) to what is called OpenGL Core 3.2, which is part of the OpenGL Architectural Review Board’s attempt to remove all of the “cruft” that had accumulated in their codebase throughout the years. In the process of doing this, they removed a lot of the nice stuff about OpenGL that makes it a good teaching tool, which is sort of annoying; you can’t just throw together a program any more and get stuff up on the screen, not without doing large quantities of work. Oh well.

On OS X Mavericks, you can only get access to OpenGL features newer than version 2.1 if you create a core OpenGL context; they aren’t even accessible as extensions, which is just flat out weird. OS X’s OpenGL implementation has been charitably described as “a mess” by everybody involved for some time, as the issue seems to be that all the driver engineering teams at Apple are now cranking out OpenGL implementations for your iPhone (and these are quite good), while neglecting the desktop platform. The situation used to be *worse* before Mavericks, if you can believe it. The net result of this is that I had to take a legacy codebase, with numerous pecadilloes, and port it to what is almost, but not quite, a new graphics API.

Your Monday Morning rendering artifacts. (Sign up for our newsletter to see more broken stuff.)

Your Monday Morning rendering artifacts. (Sign up for our newsletter to see more broken stuff.)


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