Hey folks! It's been a long time since I last frequented these parts.

I'm developing an online course on NES Game Development. In order to help students who take the course make games, I wanted to have to some sprite sheets available that they could use so they don't have to make their own resources. The name of the course is #8bitmooc, and will be a completely open course that anyone can take (with all of the course content made available under the GPL). Ideally, I want to at least have a sprite sheet for some basic game architypes, like a space game, a platformer, and an RPG/adventure. I recently finished the course infrastructure (emulator, assembler, and autograder), and now I'm working on course content. The target is to begin the course in August or so.

For those of you who don't know, the NES supports sprites that are 8x8 pixels in size. These sprites are arranged on a 32x16 table of tiles, which gives us 256 sprites for the foreground, and 256 tiles to arrange on the background (I have a template here). The NES can display 64 sprites on the screen at a time, so many "sprites" of NES games are actually composed of multiple 8x8 tiles. Sprites also only need to face one direction, since it is possible to flip them over the x or y axis at runtime.

NES sprites use 2-bit indexed colors, meaning that every sprite is able to have 4 unique colors in it (with transparency counting as one of them). The actual colors come from a palette map which assigns rough RGB values to the indices. I've developed a script that converts PNG images into NES spritesheets (and back) using the intensity of the Red value of each pixel. The template has the four grays, each corresponding to one index, with white being the transparency color.

If this interests you, or you would like to learn more about my project, I would love to talk about my project either here on in the IRC channel (you can find me in #opengameart as well as in #8bitmooc), so feel free to ping me whenever. As a teacher, I really want to see a course developed the open source way, but so far I've been the only person working on #8bitmooc so far, which is kind of disappointing. :P