Chip8 Emulator

[gerbetta]

Hello all! I was browsing the plugins that rockbox offers and I found an emulator called "Chip8."

Apparently it has all of the classics, like pong, tank, and such, and I would very much like to have this on my ipod. However, I have no clue how to put it, or the games on there.

I downloaded 2 game files called GAMES.zip and SGAMES.zip

I have extracted the files and I don't know what to do with them from here. Do I have to create some sort of folder called "chip8" and put them in there as is, or what?

I use a 1st gen iPod nano. Thanks in advance for the help

[Chronon]

This should give you enough info to get started: http://download.rockbox.org/daily/manual/rockbox-ipodnano/rockbox-buildch11.html#x14-23700011.3.2

[gerbetta]

Thanks alot Chronon, but I'm still confused on how to put them on my ipod. Do I just create a folder under .rockbox as in

H:\Chip8

or

H:\.rockbox\chip8

and do I just copy the games directly to it, and where do I put the Text file, or do I even need those?

[AlexP]

Put the games wherever you want, navigate to them in the filebrowser, then "play" them

[torne]

Someone who tried chip8 recently was complaining that many games seemed not to work or ran too fast; could you report whether it works for you?

As well as what the other posters have said, the games need to be called something.ch8 for rockbox to know which viewer to open them with.

[gerbetta]

Yeah, most of the games are really hard to play because they are really fast. Especially games like BRIX. Some games don't work at all. (I will try to get a list on here soon)

[Jason Arthur Taylor]

Someone who tried chip8 recently was complaining that many games seemed not to work or ran too fast; could you report whether it works for you?

The speed of playback was fine on the sansa clip.  That wasn't the issue.  The issues are twofold.

1.  There are two  parameters on all keyboards and bioses that says how long of a press is a single press or a repeating press and how fast repeats go.   Perhaps 1/2 second & 5-10 characters/second are reasonable, I forget.  Anyway, the # characters / second parameter seems like about 20 or so.  As a result, for many games, your character is either in one of the 4 corners at any time instead of the middle of the screen, which is impossible to get.

2.  The up and down buttons are the volume up and down instead of the pause and whatever keys in the sansa joystick on top and bottom of center. 


Both of these are emulator bugs that do not require any new lines of code to fix.

[torne]

Are you sure? If you know where the bug is, please post a patch. I suspect it is not as simple as you claim; I doubt there is any such thing as a key repeat rate in the chip8 emulator, because it's not event based; the button is either pressed or not pressed, and the game can check this state as often or as infrequently as it wants. If the game checks for keys being pressed multiple times without waiting for the countdown timer inbetween to enforce an actual time interval, then it will indeed register multiple times and there is *nothing* the emulator can do about this.

I haven't actually looked at the emulator code, so I could be wrong, but I am suspecting you do not understand how it works either

Edit: Also, if you have a suggestion for a better keymap for a plugin on some target please post the proposed changes to the tracker.

[Jason Arthur Taylor]

Are you sure?

No.

If the game checks for keys being pressed multiple times without waiting for the countdown timer inbetween to enforce an actual time interval, then it will indeed register multiple times and there is *nothing* the emulator can do about this.

Nothing?  Nothing?  Even if you are right about there being no repeat mode, it is these "we can't do it on rockbox because [insert random excuse here from set of {gpl2.42114 incompatibility, lack of memory, lack of interest, lack of need, ...}] that has lowered my expectation from the official developers here to about zero.  Do you know what the OS/2 dos emulator does with programs that look for key presses too often that are in a wait state and would otherwise monopolize the CPU?  It cuts back their cpu allocation to nearly zero. 

There is always a way, but there are always bogus excuses too.  On this board I see a great deal of the latter.  So much could be done.  So many nonsvned patches.  But so little is really done.  And why on earth should I submit a patch given that it is just going to be ignored, assuming history is a good guide.  And yes, just look at all the patches that have been submitted.  Why bother wasting time in doing that.  Either you guys decide to do it or not.  I'm not into that.  I have that right, no?  But at the same time this forum can and should save us all time if we cooperate together to eliminate duplicated work already done by someone else.  That's what I see it great for.  Cheers

[Llorean]

Oh yes, GPL incompatibility is a "bogus" excuse. We're sorry we're unwilling to break the law for you in some cases, or violate other peoples' licenses.

Lack of memory? Yes, it's simple to magically make RAM appear from nowhere.

Lack of interest? That's not a bogus excuse either - it's pretty clear you're not interested in doing it, and you admitted so yourself. So it's as bogus an excuse as you yourself make it.

Lack of need? This is really lack of interest reworded - if someone needed it, they'd be interested.

But that's not the reason here - as he said if it's doing what you said it's doing it's a problem in the software running on the emulator. We can't exactly fix glitches in other peoples' software; code to do such a thing would surely have the potential to screw up software that was working right.


I have to ask - given your history of posting on this forum and the tracker, are you simply trying to troll? You seem to pay very little attention to what is told to you (or ignore it outright, or simply refuse to believe it). You also don't even spend the time to double check things (a note: It's Paul Louden, something you could've verified by actually reading it on the patch tracker again before posting, instead of simply writing "sp?" next to it, but your laziness apparently precludes you from even taking such a simple action as double checking it before hitting post).

Seriously, if you want to contribute, make a little effort to double check things, to learn how things actually work, and to get some experience programming for these devices. Real limitations do exist, and they can't magically be solved simply because you want them to be solved.


There are dozens of patches in the tracker that sit there because they're not finished. If they're not good enough they won't be included, no matter how much you personally think they should be. The fact that you can't understand where they're lacking doesn't mean they aren't; it means you lack enough understanding of the overall situation.

[saratoga]

There is always a way, but there are always bogus excuses too.  On this board I see a great deal of the latter.  So much could be done.  So many nonsvned patches.  But so little is really done.  And why on earth should I submit a patch given that it is just going to be ignored, assuming history is a good guide. 

Do you even know how to program?

[torne]

The way Chip-8 is designed is supposed to remove the need to throttle the emulation; games are supposed to wait on the timeout register to run at the correct speed, because it was expected they would run on a wide range of systems. Most games shouldn't need any such thing. You can't throttle it in general, either; if the key detect loop is a spinloop you would need to throttle to a ridiculously low speed to make the key repeat rate acceptable and then that will slow everything down, so then you get into needing to detect key detection loops.. do you see what I mean? This is an enormous amount of effort for something that should not be needed

As for the rest, I don't really like the attitude you have here. I'm not sure what you think is magic and special about "official developers"; we're not some private club. I wrote some patches, discussed some stuff on irc, I was invited to be a committer, and now I commit stuff. If you look, we do a lot of stuff. There are a dozen or two new versions of Rockbox a day; a huge amount of stuff gets done and committed. There are lots of patches in the tracker, yes; what do you think I've been doing since I became a committer? Ah yes, looking at people's patches, and committing some of them.

Most development work does not take place on the forums; the majority of forum posts are user support. Read the logs from IRC; you will find all the things being done.

Edit: Also, you realise the post of mine you originally replied to was me *soliciting information* in order to track down if there is a problem with the emulator or not, i.e. i was intending to fix any problem that showed up. You jumped directly to explaining what was wrong (without understanding the issue) and saying what should be done to fix it (without having worked out how to do it). I don't personally have a lot of interest in the chip8 emulator but I was going to see what I could do anyway, because *people asked*. My inclination to care is disappearing rapidly now, though.