Yeah for the rendering a smooth set of RGB shifting colors using SIN you could do it in a few lines of QBASIC.
The only thing is that since the SDL example uses a 640x480 resolution, which corresponds to SCREEN 12, and in QBASIC it only gives you access to 16 indexed colors at once.
So you have to "cheat" by redefining a single entry (like index 1) throughout the loop with calculated RGB using the PALETTE command. It's basically the equivalent of palette color cycling used in some older games.
Yeah for the rendering a smooth set of RGB shifting colors using SIN you could do it in a few lines of QBASIC.
The only thing is that since the SDL example uses a 640x480 resolution, which corresponds to SCREEN 12, and in QBASIC it only gives you access to 16 indexed colors at once.
So you have to "cheat" by redefining a single entry (like index 1) throughout the loop with calculated RGB using the PALETTE command. It's basically the equivalent of palette color cycling used in some older games.