Ever wondered why GTA San Andreas' glitchy mirrors can have characters reach out of them? Don't worry, there's no underworld back there

Psst, remember the mirrors in GTA San Andreas? Like a lot of things in retro GTA games, they can be pretty quirky in a number of glitchy ways, and, thanks to one of the developers who worked on the game, we now know exactly why.

Yes, it’s the same bloke who recently revealed what was going on behind the scenes to lead to GTA 3 getting a moon that changes shape whenever you shoot it with a sniper rifle. To be fair, at least when it comes to these misbehaving reflective surfaces, there are no developer tiffs to blame.

Kicking off a tweet with the simple declaration: “glitchy mirrors in GTA San Andreas,” ex-Rockstar Technical Director Obbe Vermeij has shared the reason why the PS2 version of CJ can sometimes encounter a bunch of different weird stuff when he checks out his ugly mug. From characters and objects reaching ‘out of’ mirrors is classic horror movie fashion, to some models randomly facing the wrong way in reflections, the root cause is the same.

“We didn’t have the video memory [required] to render mirrors the proper way,” Vermeij explains, “Instead, I rendered a mirrored version of the scene, at the same time as the scene itself.” He went on to point out that the “usual” way mirrors are created in games is by rendering the scene twice, with the first render being from the point of view of a “mirrored camera”, and serving as the mirror texture, which can then be used when fully rendering the scene a second time around.

“This method requires video memory to store the first render,” the developer declared, “We simply didn’t have that spare video memory in SA.” So, there you go, that’s why the weird stuff outlined earlier was a thing on some platforms, with PC seemingly exempt due to video memory not being as much of an issue there back in the day. As Vermeij says, his solution was "not ideal, but better than mirrorless barber shops."

Helpfully, he's also confirmed that what some folks who spent hours zooming in on mirrors using sniper rifle scopes and making slightly cryptic videos about their discoveries were seeing wasn’t some kind of portal to another dimension, saying: “You could sometimes see other interiors in the mirror. There never was an underworld.”

Though, while there might not be an underworld lurking beyond San Andreas’ mirrors, it seems there are still some strange things you can do with them that aren’t explained by the way they were rendered, such as a clip of CJ firing RPG rockets through the surface of a mirror that one player’s posted in response to Vermeij’s tweet. This, according to the developer, looks more likely to be caused by “the rocket [being] created far enough from the launcher that it is already past the mirror”, therefore bypassing the collision on it.

I don’t know about you, but I feel a conspiracy theory about rockets somehow making the way to the underworld coming on.

If you're in the mood for some modern GTA, GTA Online's next big heist is set to arrive this week, and it finds a way to combine fighting corruption with chicken farms.