My first PC computer came with Hercules card! Awesome resolution, but barely can play most of the games. So I hacked one game https://www.mobygames.com/game/6522/trolls/ to run on it.
Here is what it involved, although it was barely playable. I've found where the game references the 0xA0000 addresss - e.g. the VGA 320x200, then I wrote a stupid TSR program, and had to hack in few places the game to refer to a buffer I had in my TSR (it was at fixed address, so it was easier). Then on every interrupt (I can't remember exactly what), it'll read the pixels and transforms then (well in a shitty way, that somehow made pixels work - how that last bit worked without even caring about the palette I don't know - maybe I was lucky). It was fun experiment, and it worked, but maybe 8-10fps or something like this...
Here is what it involved, although it was barely playable. I've found where the game references the 0xA0000 addresss - e.g. the VGA 320x200, then I wrote a stupid TSR program, and had to hack in few places the game to refer to a buffer I had in my TSR (it was at fixed address, so it was easier). Then on every interrupt (I can't remember exactly what), it'll read the pixels and transforms then (well in a shitty way, that somehow made pixels work - how that last bit worked without even caring about the palette I don't know - maybe I was lucky). It was fun experiment, and it worked, but maybe 8-10fps or something like this...