This is a really great project. So many retro computers are OP that they can use large frame buffers and programming to them doesn't feel like being close to the metal back like back in the day which was more intimate.

This implementation reminds me of two of my early experiences: programming display lists on Atari 8-bit and an HP PCL 5e interpreter (with short raster band buffer). I didn't really get into VCS/2600 128-byte beam racing but did do a fair amount of display-list-interrupt on-the-fly coding for homemade games and demos. I really thought the Atari Antic display list system was terrific--thanks to Jay Miner who also did the Amiga--and didn't see much like it again until OS/2 Presentation Manager or Java FX.

The PCL interpreter probably had the closest shape using a few hundred line cyclic buffer. It 'rendered' into y-sorted objects that needed to be later rendered/rasterized. Each object was cut to be at most 255 pixels (0.85") tall and used reverse max-y ordering since it couldn't be drawn until after the beam passed the wraparound scan line still rendering Y - buffer_height.