Wednesday, December 21, 2016

Questions about a gaming graphical glitch.

This is the second night in three days that I didn't sleep at all.  This time for a completely different reason than the last.  That's fucked up, annoying, damaging, and so forth.  But let's ignore that for a bit.  It's Three AM I must be . . . something.

As my mind went from thing to thing to thing {really hard to break materials from the outer realms in the Four Realms setting, what if instead of a two neck guitar you made a double wide one neck where the low notes were played underhand (traditional style) while the high notes were played overhand (think someone like Kaki King*} remember that bug from Jedi Knight?) and it was still on a graphical glitch I remember from days of yore when I gave up on trying to sleep.

So, that's where we are.

Jedi Knight, released in 1997 for Windows 95, was hardly the only game to have this going on.  It is, however, the one I remember.

So you'd be playing, you'd alt tab out, and usually everything would be normal when you went back.  Sometimes, though, sometimes you'd get these bright vibrant colors that seemed to have absolutely no relationship to the colors that were actually supposed to be displayed on the screen.

They were the kind of colors that t-shirt sales people describe as "trippy" or "Pychadelic" or "Grateful Dead-esque", ok, maybe not that last one (a lot of their merch wasn't vibrant enough to do the glitch justice anyway), but it gives you some idea of what I'm talking about.

Provided the colors didn't throw you, it didn't mess up the game at all, and you could thus play through for as long as you were willing to stay like that.

And I never knew what caused it.  And I still don't know, nearly 20 years later.  Apparently similar things are still happening if you tube results are anything to go by.

Unlike the recent results I see on youtube it did affect everything and it didn't flicker or change.  There was one way it properly rendered textures, and another way it cartoonist's~interpretation~of~drug~usage rendered textures.  No room for switching colors or only going half way.  So we come to my questions:

What causes that kind of glitch to happen?

Is there any way to intentionally force such a glitch?

Is their a specific name for this kind of glitch?

That is all.


* If you've never heard of her, you should do a search and listen.  In high school she was a drummer, and when you hear her play you'll wish that you knew how to do percussion acoustic guitar too.  Fucking incredible

I've known I wanted to be able to play guitar for ages.  My mom used to play guitar and sing to us when my sister and I were young. But I never really put much thought into how I wanted to play guitar.  In my head at the time people just played guitar or they didn't.  (Steel guitar is an entirely different category in my mind.)

Then I saw a short thing, just a blip of cable news, interviewing her, and I knew.

1 comment:

  1. The particular sort of glitch you're describing is characteristic of a palette swap in an 8-bit video mode. It's an old-fashioned kind of video display that can show many colors, but only 256 at a time. When you switch between the game and the windows desktop, Windows will tell the graphics driver to switch which set of 256 colors to use. Depending on timing, the video driver may not get the message either when you switch in or switch out, so it'll stick to the old palette, meaning you'll get a one-for-one swap of every color on the screen for whichever color happens to fill that slot in the current palette. Windows uses a palette that is optimized to basically maximize the number of distinct colors you can use, while a game typically is going to use, for example, a whole bunch of greens and grays and browns to represent grass and trees and dirt.

    8-bit linux video drivers were a lot easier to do this with since it would give each program its own palette so all you had to do was switch focus to another program and everything else on the screen would go psychedellic.

    Since this is an artifact of 8-bit video, you probably can't deliberately recreate it today exactly, but it's pretty easy to simulate. Gimp and Photoshop let you directly manipulate the palette of an image (You'd have to convert it to indexed-color first), and you can get really trippy effects by doing certain kinds of algorithmic palette swaps. Used to be common to do stuff like rotate a static image's palette through the reds in order to make it look like a fire, and the animation on the old Windows 95 loading screen actually worked that way too, rotating the blues that made up the fake-progress-bar at the bottom of the screen to make it pulse. Some older image viewers even had a button that would just start rotating the palette on images when you viewed them in case they made a neat psychedelic effect. I imagine if you google palette swaps and imagemagick there's a tutorial somewhere on making pictures of flowers look super trippy.