New Mega Drive emulator/Development environment on the way

No, I hadn't. Thanks for the link.

 

Rendering is currently performed through OpenGL, so that's portable anyway. Windows code is obviously used for the GUI, however this code is confined, and can be easily stripped out and replaced with whatever code is necessary for the target platform. No assumptions are made about endian order. Some assumptions are made about minimum sizes of certan native datatypes, but that's true of any program, and they are safe assumptions with any remotely modern hardware. All in all it should be fairly easy to port.

Input devices aren't hard coded. It will be possible later in development to have a plugin which defines a new input device, be it a controller, lightgun, modem, link cable, etc. I'll probably add support for the Menacer and Justifier lightguns myself though, as part of adding external interrupt support to the VDP.

Anyway I'm tidying up things for a first release. I hope to have a "teaser" build ready this weekend. I'm still undecided about whether to release the source with it, or hold off until a more complete build is ready. Some major areas of the code don't reflect my final design, and are merely temporary code or stub drivers. I'm doing some major refactoring right now to clean up the source, but some areas of it are still embarrassing quite frankly. Also, I don't have a clue what kind of disclamers/copyright/terms of use notes I should put with it. I'll see how much I get done this weekend and make my decision later. At any rate, I hope to have a compiled build up sometime over the next few days.

 

Ok, I guess now is as good a time as any for a first release. You can download the compiled binary from the following link:
http://fileho.com/download/444c78102373/Exodus.rar.html

I've decided not to release the source just yet, but it will be coming in the near future. Don't worry, this won't be one of those cases where a source release is promised but doesn't come for years, if at all. I will definitely be releasing the source for this emulator soon, probably with the next release.

Anyway, as for what this emulator can do right now. Currently, it's barely a shadow of what it wll be. I wouldn't quite say the GUI has just been thrown together, but it wouldn't be far from the truth. I've been debugging through a command line console, so I haven't built the debugging tools like breakpoints and tracing into the GUI yet. Most of the TLC so far has gone into the M68000 core. It's reaching the point now where the CPU core is quite solid, and I can start looking at other areas, but up until this point that's where most of the time has gone. The last week and a half has mostly gone into the VDP, which literally didn't exist two weeks ago. Most of the glitches you'll encounter are likely to be graphics related, but I've spent a lot of time crunching bugs, so a lot of games should be playable. Some games (like the regular Sonic games) are virtually flawless.

A note about speed. Currently, it doesn't matter how fast your machine is, this emulator will not run full speed. The timing code that regulates the speed of the system is only temporary, and currently it is effectively underclocking the system. That said, at this stage, this emulator will be considerably more CPU intensive than other emulators like Gens and Kega. This emulator is completely unoptimized, and the VDP in particular suffers for it. Don't expect this emulator to run well on your PIII 800. I would recommend a 2GHZ+ CPU in order to run this emulator. Exodus uses threads however, and will benefit greatly from a dual-core system. If you've got a Core2, you'll be laughing. If not, don't worry, the performance of this emulator will increase over time.

Oh yeah, a note about input. I've hard-coded in a single 3 button controller into the emulator. In order to control the game, you have to have the "Image" subwindow selected (that'll make sence once you open the emulator). The controls are as follows:
A = Z
B = X
C = C
Start = V
Up = I
Down = K
Left = J
Right = L
If you're wondering why the directional pad doesn't use the arrow keys, I was too lazy to look up the scancodes. Did I mention the interface was just thrown together?


Anyway, I'm interested in hearing what games work and what games don't. I've been testing with a limited subset of roms, but my selection is reaching the point where most of the bugs in those games have been fixed. If some of you can list some games that are thoroughly screwed, that'll give me some good places to start for hunting more bugs. If you get a game that doesn't load at all and just leaves you sitting on a black screen, just try another one. I've put in test stubs to try and prevent games blocking while trying to interact with the sound chipsets, which don't exist yet. I've come across at least one game however that I won't be able to get booting until the Z80 is up and running. If a game locks up without displaying anything at all, it's probably doing some kind of test Exodus isn't faking out during the initialization of the sound.

Oh, a couple of notes on the VDP, so you know what's a bug and what's simply not done yet:
-Horizontal interrupts are implemented, but are unreliable in some cases due to timing issues. Things like water will not work correctly in the Sonic games, but it'll give it a go.
-I've attempted to support sprite overflows/masking, but they're not working right. I haven't confirmed yet whether that's due to an error on my part, or incomplete documentation.
-As previously mentioned, interlace modes and shadow/highlight mode are currently not supported.

Anyway, I think that's about it so far. Enjoy.



PS, Thanks for that license Aurochs, I'll probably modify it slightly and use it when I release the source.

 

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