If I want to make a 3D game, and I want all my textures to be 8 bit, to save RAM, that is 256 indexed colors, including "transparent", how do I choose the colors?
Is there any recommended pre-defined palette? (Link?)
The end-rendering would use full colors, based on lighting, ...
If I interpret your question correctly, you want to know which 256 colors to pick to a palette to make things look good.
This is called the black magic art of color reduction. There's plenty of ways to perform it, some work better than others, and all of them are wrong, as what you're doing is removing information.
One common way is to place all desired colors into an octree and then reading out the 256 biggest cells; another is to do median-cut of the color space until you have 256 segments.
Easiest solution would probably be to drop all the desired colors into photoshop (or something similar), and convert to 8-bit paletted picture. Photoshop, at least, contains variety of methods to do the conversion.
This is more useful for website design but the theory of how colours work together should be applicable anywhere:
http://colorschemedesigner.com/
If you’re set on 8-bit colour, just remember that you won’t have enough to do lots of intricate shading; your models can end up looking quite flat or cartoony (but that may be the look you’re going for). Wikipedia has a list of some of the palettes other people have used:
http://en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes
A few points:
Modern video cards and drivers has a texture compression feature that pretty much defeat the purpose of this question. You get good looking textures at low memory and memory bandwidth consumption. You can't compress paletted images in the same fashion.
It is correct that you are not even close to having made a game yet? Then why are you asking such a tech question? Stop stalling on possible future issues and get to work.
A kind of answer:
As for making a global 8 bit palette, I think you'd get the best results from something like a table with all the possible combinations of colours with 4 different blue values, 7 red values and 9 green values.
In modern computing colour palettes are used mostly for storing images, png images will often grow a lot smaller when converted to 8 bit, and for a lot of their typical use cases the difference is unnoticeable. But this is almost always done with a pallette generated specifically for that image as that can provide way better results than a standard palette.
I would say it depend on what kind of feeling you would like to achieve. If you would like to have some creepy game you will have differente palette (gray/dark colors), then for game some casual "happy" game.
I think the link Sullivan provided is good, if you need Gameboy like palette.
I can't give you exact colors, nobody can. BUT if you are looking for an inspiration I would recommend http://kuler.adobe.com/
Be aware, colors presented at kuler.adobe.com are usually for web designers. But they might give you some idea.
