Would you like to play Nokia (J2ME) games on Retropie?

recompile

I'll give this an emphatic Yes.

There are a lot of great J2ME games that you simply can't play anymore. There were a lot of big-name titles from popular franchises, for example, from that era where J2ME ruled the mobile space. Doom RPG is one of my favorites, but only works in one, abandoned, closed-sourced emulator.

I'd say the project is worth the effort for preservation alone. I can guarantee that your efforts won't go unappreciated.

The only open source emulator that I'm familiar with is MicroEmulator, but it's also been abandoned. Reviving that, or any other open source J2ME emulator, would be fantastic.

Hex

@recompile Yes I was planing on resurrecting micro emulator. The problem would be to have a per game config file as you might not have same number of keys as are present on the mobile phone (18).

The list of j2me games, which now I would classify as retro, is so vast. There are amazing racing games like Asphalt 8, Prince of persia etc which would all be quite awesome

mediamogul

When you list all the potential games this would open up, it does sound pretty nice. I always like to discover new retro titles, so I'd definitely use it.

Hex

@mediamogul For a comprehensive list check this out :
https://www.google.com/search?q=j2me+games

mediamogul

@Hex

The ID software turn-based shooter RPGs look especially interesting.

recompile

@Hex That might not be too bad. While I envision playing with a mini wireless keyboard and a controller, I think a good default controller layout would work fine for a lot of games, saving players a bit of effort.

I'm thinking something like the d-pad for the nav buttons, L and R for the soft keys, the ABXY buttons for *, #, 5, and the center nav "okay" button, select for 0, and the left analog stick for 2, 4, 6, 8. The remaining 1, 3, 7, and 9 could be mapped to the right analog stick, though that's not as clean as the other mappings.

Not having a number pad on the controller is problem for systems like the ColecoVision as well, which is why I have a mini wireless keyboard, but it works well enough.

Where you'll really need per-game configuration is in display size. Some games won't work, or won't work properly, if the display is too large or too small.

You could do that inside the emulator, perhaps with a button combination to bring up a config menu. You could allow buttons to be remapped there as well.

mediamogul

@recompile

Ha! I just noticed you're avatar. You must have to beat the ladies off with a stick.

Hex

@recompile Not everyone has all these buttons joysticks etc.

I am thinking of keeping it to 10 buttons. Dpad+ABXY+StSL no more than that. Optionally L&R. I am thinking of a way to make things work with as few buttons as possible. You could have a config file specified that you can put your mapping to.

cyperghost

@mediamogul Yes I thought you are cloned like Dolly

meleu

@Hex a few weeks ago a friend of mine was working on J2ME libretro core. I'm not sure how far he went, though. I'll discover and let you know.

recompile

@Hex That's a tall order. You'd need to pick a modifier key, with the rest doing double-duty to hit all 18 buttons.

If I remember correctly, a lot of games that use the nav buttons also use 2,4, 6 and 8 as directional keys and 5 for 'okay'. If you used X for the modifier key, you could try something like start and select for the softkeys, the d-pad for 2, 4, 6, and 8, Y for 5, and A and B for * and #. If you use the d-pad and modifier together for nav, you have just enough buttons between start, select, A, B, and Y for 1, 3, 7, 9 and 0, though it'll be awkward to hit A, and Y when holding the modifier. That's the best I could probably do as far as a sensible default for 10 buttons is concerned.

I have to wonder though, how many controllers have 4 buttons, start, and select but don't also have L & R? You might be making it more difficult than it needs to be. It would be an easy decision to use L or R for the modifier if you don't mind upping the minimum button requirement.

Now that I'm thinking about it, you could drop the requirement to 8 buttons, if you used 3 modifier keys, allowing one to use one of those USB NES controllers. It would be pretty awkward to use though. Math says the absolute minimum is 5 buttons for 18 functions, but that would be absolutely awful (or impossible, in the case of a 2600 joystick) to actually use.

Oh, I forgot about something else odd about J2ME games. Some games used APIs from vendors (Nokia, Siemens, etc.) so you might need to include that in the per-game configuration.

@Hex Yeah, I noticed that when I wrote the fix, but I didn't want to modify the sprites. I thought it was funny that documentary crew at the dig covered his shame in their artwork.

Hex

@recompile said in Would you like to play J2ME games on Retropie?:

@Hex Yeah, I noticed that when I wrote the fix, but I didn't want to modify the sprites. I thought it was funny that documentary crew at the dig covered his shame in their artwork.

What??

Hex

@meleu Yea it would be better that way. Let me know what you find out.

recompile

@Hex Sorry, that was supposed to be @mediamogul. I tried to edit that when I noticed, but aksimet decided that change made my post spam. Frustrating.

mediamogul

@recompile

I thought it was funny that documentary crew at the dig covered his shame in their artwork.

Ha! I missed it. That is funny.

pjft

I don't know a lot about these games, but if lack of keys are a problem, the ZX Spectrum emulator solves that by showing a virtual keyboard when Select is pressed. I imagine that some keys will only be used rarely, so that can be an option!

meleu

@Hex said in Would you like to play J2ME games on Retropie?:

@meleu Yea it would be better that way. Let me know what you find out.

He said:

"I wrote the code to read ZIPs/JARs, read info from manifests and load .class files to memory.

Theoretically I could start to interpret Java bytecodes, but other priorities had come, and I thought that maybe it's better to use the SableVM than maintain my own JVM. Anyway, it didn't evolved."

Hex

@meleu Sable reached its End of Development in 2007. I might have a look there too. I tried playing some game and lot of them need only these keys

Yes & No
Dpad keys + Enter (AKA yes key)
1,3,7,9

So this seems doable. Yes no can be start and select, Dpad = Dpad and 1379 XYAB. So all in all its very much plausible. Now i need to find a good java dev to help me with setting up the build env. Know anyone who can help?

recompile

@Hex It looks like ME was using maven 2, which is end-of-life. Eclipse can create and Ant build file for you, if you or contributors want to use something other than Eclipse for builds.

I'd start by downloading the Java SE SDK and setting up the project in Eclipse. Once you can successfully build, install Ant and create a build file.

The read-me-developer.txt on the version on GitHub should fill-in any gaps.

I can try to get something working later in the week if you're having trouble, but it doesn't look like it'll be too difficult.

Hex

@recompile if you can get it running then I would get on it ASAP. Let me know how it goes. I am currently focusing on PS and hence unable to divert much time in things i dont know about. Can you set it up and let me know how it goes. Thanks.