Various folks have disassembled the Asteroids arcade ROM. This was helpful recently when I wondered how collision detection was implemented. It turns out to be a sort of axis-aligned octagon intersection algorithm that was easy to implement with just a few adds, subtracts, & compares (6502 doesn't have multiply or divide).

https://github.com/nmikstas/asteroids-disassembly/blob/maste...

(the commentary of the same lines at https://computerarcheology.com/Arcade/Asteroids/Code.html is incomplete by comparison)

My interpretation of the code is that it leads to an effective shape like the one in this graph, where the overall size is determined by the sum of the size of the two involved objects:

https://www.desmos.com/calculator/k63qoshhqx

Commodore version conserved (& enhanced) @ https://github.com/asig/MAD_computer_program

I went looking for old screen capture programs. The first place I checked was simtel (https://archive.org/details/SIMTEL_0692), and found multiple copies of an EGA screen capture program from 1987, such as "CAPTURE.ARC 21504 06-11-87 Screen capture to disk file (from PC Magazine)". There was also an earlier dated file for dumping Hercules screens to Epson printers.

The sibling point about digital prepress is a relevant one too: So you have a file on your computer with the contents of a screen .. whatcha gonna do with it anyway?

also https://intarch.ac.uk/journal/issue59/3/index.html [linked from spc746's article]

Related: This is powered by 'c2t', open source software on github. I made a web-based port of c2t that can take a .dsk file from your computer and produce a sound file: https://www.unpythonic.net/web-c2t/

just noticed that if you feed it a .woz file, it segfaults. nice.

source: https://github.com/jepler/web-c2t with the heavy lifting by https://github.com/datajerk/c2t