I.K.E.M.E.N GO on Raspberry Pi 4 [Now with an Install Guide!]

[BuZz]

@superfromnd Thanks for this. I have done a quick review only so far but appreciate the contribution.

[SuperFromND]

Good news for composite-out/CRT people like me! I figured out how to make IKEMEN GO center itself in windowed mode, and thus display properly on CRT without an overscan hack!

Jools gave the scriptmodule a quick review and informed me of a few things that needed to be rectified, and one of them was the removal of a few unnecessary dependencies that were rendered redundant by their -dev package variants.

Well, it turns out that the binaries installed by apt-get install xorg were the cause of IKEMEN GO not centering itself! Simply removing the package was all it took to fix it, and now it displays at the proper size on CRT (which looks pretty awesome and elegaic when you turn off all the other lights, by the way):

[SuperFromND]

Progress report on the RetroPie submission: The review noted a few things that needed to change in the script. Most of it was relatively easy stuff, like using the git_module_repo system and some minor re-ordering of commands. The one that's proven to be more difficult is minimizing the number of dependencies that are installed. Here's a quick re-cap of those:

• golang-go: Required; this is the language IKEMEN GO is written in.
• libgl1-mesa-dev: Required; Go-GLFW dependency.
• xinit: Required; this launches the X server for displaying the game.
• xorg: See below.
• xorg-dev: See below.
• libopenal1: Not required; libopenal-dev makes this redundant.
• libopenal-dev: Required; Go-GLFW dependency.
• libgtk-3-dev: Unsure. Originally added due to errors early on in this project.
• libasound2-dev: Required; Go-GLFW dependency.
• freeglut3-dev: Not required. Originally added due to errors early on in this project.

The two that have proven to be the most contentious are xorg and xorg-dev. xorg-dev is a dependency for Go-GLFW, and theoretically xorg is unnecessary... right? Well, no, because if you exclude it in the scriptmodule, Xinit crashes due to not being able to find X:

Parameters: 
Executing: xinit /dev/shm/retropie_xinitrc -- vt1 -keeptty

xinit: unable to run server "X": No such file or directory
Use the -- option, or make sure that /usr/bin is in your path and
that "X" is a program or a link to the right type of server
for your display.  Possible server names include:

    Xorg        Common X server for most displays
    Xvfb        Virtual frame buffer
    Xfake       kdrive-based virtual frame buffer
    Xnest       X server nested in a window on another X server
    Xephyr      kdrive-based nested X server
    Xvnc        X server accessed over VNC's RFB protocol
    Xdmx        Distributed Multi-head X server

xinit: giving up
xinit: unable to connect to X server: Connection refused
xinit: server error

So by process of elimination, xorg-dev is the one that would need to be removed and xorg by itself is good. Mystery solved... right? Well, no, because if you have just xorg installed, then IKEMEN GO can start correctly... until a K.O. is achieved, which causes IKEMEN GO to crash with an error like this:

./external/script/randomtest.lua:257: ./external/script/start.lua:1251: __len undefined
stack traceback:
	./external/script/start.lua:1251: in function 'f_turnsRecovery'
	./external/script/global.lua:239: in function 'loop'
	<string>:1: in function <<string>:0>
	[G]: in function 'game'
	./external/script/randomtest.lua:257: in function 'f'
	external/script/main.lua:2992: in function 'loop'
	external/script/main.lua:3076: in function 'loop'
	external/script/main.lua:4051: in main chunk
	[G]: ?
stack traceback:
	[G]: in function 'game'
	./external/script/randomtest.lua:257: in function 'f'
	external/script/main.lua:2992: in function 'loop'
	external/script/main.lua:3076: in function 'loop'
	external/script/main.lua:4051: in main chunk
	[G]: ?

It seems as if xorg-dev isn't installing certain packages that xorg is, but at the same time xorg isn't installing something that's causing IKEMEN GO builds to be a little screwy as a result. Installing both does seem to fix the problem, but I imagine that's not ideal for RetroPie's maintainers.~

There's also the possibility the real cause is something less severe; these changes were made at the same time as some directory-creation and permission changes, so it's completely possible that IKEMEN GO just isn't able to read or write something and that's causing it to go kerpoot somehow.

ADDENDUM: Scratch all that, turns out I was just being a tad paranoid; this doesn't seem to be a bug with the libraries, and xorg on it's own is sufficient after all. My reasoning: there's a consistent way of reproducing this crash, and there's a consistent way to fix it too:

Starting up IKEMEN GO and going straight into Random Test causes the crash, but going into any other mode first and then Random Test averts the crash. I've actually seen this exact behavior when trying to make my own LUA addons before, so it's possible this is a bug on IKEMEN's side and not on the Pi specifically. Crisis averted.

ADDENDUM 2: This was indeed a bug on IKEMEN's side, and one of the devs fixed it once I posted about it. That's a relief.

[duiz]

@superfromnd Amazing to see such rapid progress on this. This might be the most exciting addition to RetroPie IMO.

[joamjoamjoam]

@superfromnd

Sweet looks good. I'm curious as to what the issue was so ill cruise by the Github and check it out.

Out of curiosity how does the Retropie/Script pack process go. Do you submit it to them for addition to the experimental packages??

[SuperFromND]

@joamjoamjoam Correct! You create a scriptmodule and then PR it to the RetroPie/RetroPie-Setup Github for approval. If it's merged, it's added.

The randomtest fix was apparently this.

[joamjoamjoam]

@superfromnd oh nice seems like it was completely unrelated a to a CRT or fullscreen then. Sweet let me know if there is anything else I can help out with to help make this a reality.

Side Note: I did find another bug on the pi side only where the command list for the characters is drawing some random white triangles when you try to view it. I might take a look at it this weekend. If i can confirm it ill post an issue in github to track the progress. Its most likely another difference in precision thing.

[SuperFromND]

@joamjoamjoam Oh actually, that command-list text bug isn't Pi-specific! Some AMD cards were getting that on IKEMEN on PC as well; it's apparently supposed to be fixed when the next version of IKEMEN is released (v0.98, sometime either this week or next week). No idea if that fix will also apply to the Pi though, so I guess we'll have to wait and see.

[joamjoamjoam]

@superfromnd oh that’s good to hear. The command list of probably my favorite Ikemen feature over the regular mugen cause I always forget the inputs.

[Troopaking]

@superfromnd
Hello again so as you've seen we made decent progress with mugem through box86 i think performance with mugen/ikemen will be better with ikemen go . Due to pi accepting go language better than comping and running through wine.
I see you made some changes to stuff since my last comment.
I will be trying to reinstall your scripts this evening to see if it works for me .

Should I use your retropie scripts and then do fixes discussed or have to updated the scripts fixes not needed?

[SuperFromND]

@troopaking The scripts alone should work just fine (at least the one over on the PR I've submitted).

[SuperFromND]

So while I've been waiting to hear back on the PR, I figured I might as well get a head start on writing documentation for the RetroPie Docs. Obviously my documentation won't (and can't) cover every single thing IKEMEN GO can do (that's probably best left to IKEMEN/MUGEN's devs and community at large), but nonetheless I think it should be at least useful for getting stuff up and running for testers who aren't familiar with IKEMEN / MUGEN, or who just need a refresher on how it all works.

Here's what I've written so far:

---

---

I.K.E.M.E.N GO is an open-source implementation of the M.U.G.E.N fighting game engine, originally developed by Elecbyte in 1999, written using the Go programming language. I.K.E.M.E.N GO adds many additional features and bug fixes, in addition to being backwards compatiable with content created for M.U.G.E.N.

---

Ports: I.K.E.M.E.N GO

ROMs

Place your M.U.G.E.N / I.K.E.M.E.N content in:

/home/pi/RetroPie/roms/ports/ikemen-go/

A typical file structure should look like this:

ikemen-go
|-- chars
|    |    (character folders should be placed here,
|    |    preferrably containing a .def file with the
|    |    same name as the folder that contains it)
|    |
|    + -- kfm
|         | -- kfm.def
|         | -- kfm.sff
|         | -- kfm.snd
|         | -- kfm.cns
|         | -- kfm.cmd
|         + -- (etc.)
|
|-- stages
|    |    (stage files should be placed here, typically
|    |    they come with a .def, a .sff, and an audio file
|    |    that must be placed in the sound folder)
|    |
|    | -- stage0.def
|    + -- stage0.sff
|
|-- data
|    |    (screenpack / motif folders should be placed here)
|    |
|    | -- system.def
|    | -- select.def (edit this to add characters/stages)
|    | -- fight.def
|    + -- (etc.)
|
|-- external
|    | -- icons
|    | -- mods (place additional LUA scripts here)
|    | -- script
|    + -- shaders (place GLSL shaders here)
|
|-- font
|    |    (additional fonts should be placed here, some motifs
|    |    might keep their fonts in their own folders however)
|    |
|    | -- default-3.5x.def
|    | -- default-3.5x.sff
|    | -- f-4x6.fnt
|    + -- (etc.)
|
+-- sound
     | -- (optional stage audio files go here,
     + -- currently MP3 and OGG are accepted)

Adding Characters / Stages

Once the character folders and/or stage files are extracted, the following file must be edited in order for them to show up on the select screen:

/home/pi/RetroPie/roms/ports/ikemen-go/data/select.def

The file contains a list of all the characters and stages, listed with either a folder or file name, along with optional extensions, extra file pathing, and other options if needed:

[Characters]
kfm
kfm720/kfm720.def, stages/stage0-720.def
randomselect
 
[ExtraStages]
stages/stage0.def
stages/kfm.def

See the comments in select.def for more information.

Controls

Controls can be configured in-game by going to Options -> Input Settings -> Key Config / Joystick Config -> Config All, and are located in:

/opt/retropie/configs/ports/ikemen-go/save/config.json

Default controls

Note that control schemes can vary wildly on a per-character basis.

Key	Action
ESC	Pause / Back
Left/Right Arrow	Move left/right
Up Arrow	Jump
Down Arrow	Crouch
Left Arrow while opponent is attacking	Block
Left Arrow x2	Back Hop
Right Arrow x2	Run
Z	Light Kick (A)
X	Medium Kick (B)
C	Strong Kick (C)
A	Light Punch (X)
S	Medium Punch (Y)
D	Strong Punch (Z)
Enter/Return	Taunt (Start)
F12	Take Screenshot

Configs

Options can be configured in-game via the Options menu. A default configuration file is generated upon first run, located in:

/opt/retropie/configs/ports/ikemen-go/save/config.json

It is recommended to enable Fullscreen for the best experience.

---

Am I missing anything important or obvious? Aside from possibly an Issues section, I think this covers most of the essential stuff.

[DTEAM]

@superfromnd said in I.K.E.M.E.N GO on Raspberry Pi 4:

Am I missing anything important or obvious? Aside from possibly an Issues section, I think this covers most of the essential stuff.

Great work!! Maybe you should put that on the top of your first post like @Folly did here..

The instruction will be easier to found for newbies or new users. Are you agree.

[TheSnackist]

@superfromnd I would probably be wary about making blanket generalizations about controls - while many characters (especially in the Capcom style) have 6 button gameplay and back arrow to block, it's not nearly as universal as this post would lead some to believe - it's hard because every character controls differently - maybe say to refer to indivual character readmes for details on controls?

You could also recommend Googling 'such and such MUGEN' for additional help - I feel like anyone who starts to tinker is going to get the most out of Google and reading the documentation.

Damn excited to give this a go... I think I have to update from an older Raspbian base first so wish me luck on thaaaaaat

[SuperFromND]

@thesnackist Good points! I still think I'll include the controls chart, but I'll just omit block, run, dash, and re-label ABCXYZ to their generic labels rather than specifically calling them Light Kick, Strong Punch, etc., since that's what Elecbyte's own documentation does.

I also agree that it would be a good idea to include some mention of "for more information, see also: MUGEN's documentation on bla-bla-bla", maybe links to both Elecbyte's documentation and IKEMEN GO's documentation in specific as well.

Oh, and good luck on the Raspbian update!

[SuperFromND]

I submitted my documentation as a PR on Github; obviously not to be merged until IKEMEN GO itself is added over on the RetroPie-Setup repository. You can read the current draft here!

[TheSnackist]

@superfromnd Dope!! This is a solid enough introduction to cover the most common questions - how do I add characters I downloaded, how do I add stages, what do I need to edit, etc.. Really impressed!! You've boiled the complexities of this engine down to something simple and easy to understand.

EDIT: Until the RetroPie devs approve the pull/commit request, is there a way to use the git command to add the proposed script module to our own setups?

[SuperFromND]

@thesnackist I don't think that Git has any command to pull a single file and place it in a specific directory, but since I'm using Github, it's pretty easy to just wget the scriptmodule file from my fork and download it to the appropriate place:

# Downloads the scriptmodule to the scriptmodules/ports folder
# You may need to change the directory if you're using 
# a different location for scriptmodules

# Note that this will become obsolete if the PR is merged

sudo wget https://raw.githubusercontent.com/SuperFromND/RetroPie-Setup/master/scriptmodules/ports/ikemen-go.sh -P /home/pi/RetroPie-Setup/scriptmodules/ports/

[TheSnackist]

@superfromnd after some tinkering I got... somewhere :/

when I try to build ikemen-go it can't find a bunch of the packages

let me try to figure out how to export the log... my network doesn't like SSH so I can't just grab it easily

[SuperFromND]

@thesnackist Quick question while you're trying to fetch that log, just a hunch: have you tried updating RetroPie-Setup before running the script?

RetroPie recently updated their scripts to use a new command for downloading source-archives which my script uses; this command isn't in the version of RetroPie-Setup that's included with new installs via the image on RetroPie's site yet (it will be whenever the next version of RetroPie releases, but for right now you'll need to update RetroPie-Setup first).

If that's not the problem and it's instead Golang that's having problems fetching packages... that's a bit more of a problem, but given you mentioned your network not liking SSH it's plausible it might also be having problems trying to fetch the Golang packages needed to compile IKEMEN GO.