moa VS rust_minifb

The code is here if you're interested: https://github.com/transistorfet/moa System is the top level component and devices.rs has the traits that System uses to interact with the components. The machines directory has the system definitions that build a specific machine to emulate.

A few months ago, I wrote a 68000 emulator in Rust named Moa. My original goal was to emulate a simple computer I had previously built. After only a few weeks, I had that software up and running in the emulator, and my attention turned to what other platforms with 68000s I could try emulating. My thoughts quickly turned to the Sega Genesis and without thinking about it too much, I dove right in. What started as an unserious half-thought of "wouldn't that be cool" turned into a few months of fighting documentation, game programming hacks, and my sanity with some side quests along the way, all in the name of finding and squashing bugs in the 68k emulator I had already written.

There's not much to it. Only one window can be created at the moment, and input is not yet supported. The threaded option is also not shown here. Before long, the code grew more complicated, and now includes parsing of command line arguments with the clap crate. To see the latest version, check out the Genesis machine-specific binary and the MiniFB host impl and main loop

Since the 68000 has a reasonably orthogonal instruction set, we can break down the opcode word into sub-components, and build up instructions by separately interpreting those sub-components, rather than having a match arm for each of the 65536 combinations. There is a really helpful chart by GoldenCrystal which shows the full breakdown of opcodes for the 68000. We can look at the first 4 bits of the instruction word to separate it into 16 broad categories of instruction, and then further break it down from there. The full code can be seen here

Well, it depends on how you use it; writing to an image buffer isn't much less efficient than writing to any normal buffer (in fact, although displaying your scene to a window efficiently is important, your main bottleneck will be the actual ray tracing loop). You may want to read this article for a practical example of using an ImageBuffer to create and draw a texture with Piston. Other window backends you could use, apart from pixels which was already mentioned in another comment, include minifb and Mini GL, though I haven't personally used them.

After watching the Numberphile video on this formula, I decided to implement it in Rust for fun. It uses minifb for the window creation + framebuffer.

Before I could implement the display output, I needed something to draw the images onto. There are quite a few Rust crates available to create a GUI window and update it with 2D graphics. Most of these are of course intended for making games, and also include ways of getting key presses as input, which I'll also need. I looked at Piston, which I've used before on other projects, Macroquad, which also supports web assembly as well as desktop targets, Pixels, which is intended specifically for 2D games, and Minifb, which is also specifically for 2D applications, but is much simpler. I also tried out libretro, which is specifically made for video game emulation, but I found it much more restrictive than the others because of it's narrow focus.

There's several different approaches you could take, but I'd probably suggest macroquad as the easiest. I've also used minifb for windowing + a drawing library like raqote or tiny-skia.

I don't know much about Rust, but I used the C version this library, and I think this is as simple as it gets: Rust MiniFB. Hope this helps

A very simple color manipulation library backed by a u32. My use-case was for use with minifb which uses a u32 frame buffer. Feedback appreciated.

If all you need is a pixel/frame buffer I'd suggest either pixels-rs or minifb.

In my experience, it really makes no difference what rendering backend you use for something as simple as a NES emulator. The 'pixel_renderer' that i wrote basically does the simplest possible thing i could think of - it takes a pixel buffer in cpu memory, copies it over to the gpu, turns it into a texture and stretches it to cover the entire screen. There seem to be many crates out there that do just this - my choice to roll my own was really one out of curiosity and completionism more than anything.