Use the left and right arrow keys to rotate the screen. It's quite glitchy at the moment. Also, press W to toggle wireframe, which isn't glitchy.
So, I was trying yet again at making a Mode 7 engine. I'm using weak perspective projection again, and it's working fine, probably because the points only vary in 2 dimensions, not 3. Update: In this update, I finally fixed the rotation glitch! I tried to implement @DadOfMrLog's triangle filler, but it's clearly glitching... There's still a lot to do before it's ready to use: 1. Fix the glitch with the tri filler! (Might just make my own...) 2. Allow the user to move forward and backward instead of just rotating. Again, this should be easy to do; I can simply translate before the rotation so the translation will be affected by the rotation as well. 3. Allow the thing to read from a list. Right now, I have to hardcode the map. 4. Add sprite support. If I want to make a Mario Kart-like game, I'll need sprites for racers, trees, pipes, etc., and they'll need to move in a 3D fashion. 5. Release the full version, probably on my main account (@redyoshi857).