Game Emulation for Screenshotting/Sprite Capturing Purposes

[TheRewster]

Hi folks--first time spriter here. There are some NES games I'm looking to obtain sprites from. The main method I plan to use for now is using screenshots from an NES emulator (VirtuaNES). But I don't want to have to actually play through these games all the way again when all I'm looking to do is just to pick up a bunch of sprites (The Lost Levels and Zelda II would particularly be annoying to play through)--that and I can't play worth a squat on a computer keyboard anyway.

So are there ways to just cruise through emulation versions of games to pick up screenshots that I need? Maybe a cheat code to make my character invincible/able to hover through stages, something like that?

Also, while I know I can pick up many of the sprites here on this website (and I have downloaded quite a few sheets), I'd prefer to do it myself simply because I've noticed some mistakes on certain sheets, plus I never know if a sprite sheet is using the exactly correct palette, etc.

[Firejoker54]

You're going to waste your time re-ripping sprites. There is no correct/official NES palette. Of course it varies between emulators but your rip won't be the "right one" either.
In any case, this site may help you:
https://gamehacking.org/system/nes
I'd suggest actually getting good at games though. There's not a cheat code for everything

[TheRewster]

I can hold my own at video games well enough. (Hell, one time I beat Zelda II without a single game-over.) I just can't play worth a darn on a computer keyboard.

I'm a little surprised there is no one right palette. I guess if nothing else my main concern then is consistency. If I take enemies from one sprite sheet for instance, then take items or objects from a sprite sheet submitted by a different user, there are sometimes inconsistencies with the palette (I've already noticed this with the Super Mario Bros. 3 sheets on this site). Which is why I'm considering ripping my own so at least I know they're all from the same source.

Thanks for the link.

[puggsoy]

Some games will have cheat codes, but it varies. Some might also have various save files available online that allow you to skip sections. But there's no full-proof way to avoid playing the game if you're looking to hard-rip.
There are other ways like tile-ripping, but that can get tough. It's a lot of fiddling with tile editors and piecing things together.

The reason there's no "true" palette is because while on modern computer we use 24-bit colours (if you ignore alpha), the NES was restricted and didn't follow the same rules. This is similar to a previous discussion about the Game Boy colours. The GB's palette was basically grey and had 4 levels of greyness: 0, 1, 2, and 3. It didn't use 24-bit RGB, so there aren't any values in that format to grab. Mathematically, we could split the 24-bit colour range into 4 equally spaced parts:

#000000
#555555
#AAAAAA
#FFFFFF

However, that's assuming that the Game Boy's black was the same as #000000, and that its white was equal to #FFFFFF. Then we also have the can of worms dealing with how the screen was actually green-tinted, and whether you would consider that more "true" of a palette than simply grey.
The same kind of goes for the NES. The fact of the matter is that people who make the emulators have simply had to do what they deem is the best approximation of converting NES colours to 24-bit RGB, and unfortunately that isn't always consistent.

All that being said, this Wikipedia article seems to get about as on-the-nose as you can get with this, so it's probably the best you'll find.

As for keeping palettes consistent for your uses, I feel like it'd be easier to simply replace the palettes of sprites manually to match whatever you want them to, rather than re-ripping them. In GIMP you can do this using the colour select, or even just by converting the image mode to indexed with a custom palette. I'm not sure what the equivalent would be in other programs but it's likely something similar.

[TheRewster]

Thank you Puggsoy--that was a very informative response. That Wiki link was particularly useful!

That's interesting about the Game Boy palettes. I was always under the impression that the sprites themselves are black and white, while the screen itself is what's green. (Kind of like when you have one of those ceramic Christmas trees--the bulbs are all sorts of different colors, but the light you put underneath the tree to light them all up is a white light.) I'm curious what other people's thoughts on that are.

[puggsoy]

The display itself is green, i.e. its pixels output different shades of green. So it isn't just a black-and-white display that is shaded green by an overlay, if that's what you mean.

The Game Boy Pocket did have an actual black-and-white display though. The sprites themselves aren't necessarily black-and-white, or green, they're just varying shades of luminance (their pixel values are stored as numbers between 0-3). What colours you saw depended on what kind of screen that luminance is displayed on.

[TheRewster]

The display itself is green, i.e. its pixels output different shades of green. So it isn't just a black-and-white display that is shaded green by an overlay, if that's what you mean.

The Game Boy Pocket did have an actual black-and-white display though. The sprites themselves aren't necessarily black-and-white, or green, they're just varying shades of luminance (their pixel values are stored as numbers between 0-3). What colours you saw depended on what kind of screen that luminance is displayed on.

Ah, I did not know that! Like I said, I'm new to all this. But that's good to know.