OpenGL programming, simple FPS style walking scene (DOS, 256 colors, dithering, OSMesa)

In this tool-assisted education video I create a simple FPS style walking and jumping scene for OpenGL, with DJGPP, in DOS. In a 256 colors 320x200 VGA mode. This is my first OpenGL exercise.\r
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Apologies about some little mistakes in the program (such as reloading the textures on every frame). I noticed them when this video was already late in production, and it would take several days before the new version would be available if I were to fix them, and Im itching to get this video out and into making the next video already, and none of the mistakes ually prevent the content being understood, so Ill leave them be. Most people dont even notice.\r
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Twitter: \r
Patreon: (alternatives at \r
Twitch: \r
Homepage: \r
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I wrote a FAQ after this video was picked up on Reddit the first time in new. Here it is: \r
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Source code and prebuilt lightmaps: (Compiles and runs on Linux):\r
(includes also a superior ellipsoid-based collision testing, and a buggy WIP for portal rendering: Im not good with the math.)\r
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The background music is The Last Duel/The Final Decisive Battle from Lufia I/II (SNES). However, it is not played through the SPC700 (SNES audio chip), but through OPL3, the FM synthesizer in PCs. You can see my process of converting a SNES song into an FM song in this video: