lr-dosbox-svn / lr-dosbox-core (new dosbox libretro cores)

muldjord

So it would seem that the current lr-dosbox is (being) deprecated by libretro. They are moving development to a more regularly updated core which is more closely connected to the upstream dosbox code. It is located here:
https://github.com/libretro/dosbox-svn

I'm concluding this on the basis of several issue tickets files under the old lr-dosbox core (for instance here: https://github.com/libretro/dosbox-libretro/issues/122), which basically says that development has seized on the old core and they are now focused on the new core which seemingly is, already at this point, feature-comparable to the old, but is based on the newest DosBox.

So I decided to dig into it a bit. I copied the current lr-dosbox.sh RetroPie script and converted it to clone and compile the dosbox-svn core instead. Not much needed changing although I had to add libretro as the branch it should clone as supperted by the gitPullOrClone helper.

It compiled fine and I got my dosbox_svn_libretro.so lib and it was added properly as lr-dosbox-svnas I had named it. All good!

I tried starting it manually from the cli with /opt/retropie/emulators/retroarch/bin/retroarch -L /opt/retropie/libretrocores/lr-dosbox/dosbox_svn_libretro.so --config /opt/retropie/configs/pc/retroarch.cfg and it launches fine and I get a DOS window as expected. Nifty! And I can exit it with the usual retroarch button combination, so all seems fine.

I had a look at the sources from the core and can conclude that it should be able to launch .conf files directly and looking at issues posted by users seemed to suggest it as well. Meaning that no changes should be necessary from the default core initialization string when running it directly with a Dosbox conf file as the "rom".

But it didn't work. The core simply seems to segfault even with the simplest .conf file only containing a few [autoexec] commands. It worked with a .bat file though... Which seems to suggest some kind of internal parser issue. Maybe it tries to load the conf file as a bat file or similar. I dunno, I'm going to bed soon, so don't have more time to look into it today.

So that's where I am at at the moment.

I'll look further into this over the coming days when I get the time. But for now I would like to know if the RetroPie team are interested in integrating this new core sometime soon as an experimental. I have the script ready here on my machine. It's based 99% on the current lr-dosbox script, mainly corrected the git repository and added the required branch (it won't work with master).

Let me know what you guys think about all of this if it catches your interest. I really love being able to launch .conf files directly, without having to use an .sh script or similar. It seems the best way in my opinion.

Rion

@muldjord Nice to see more interest in this new core.

I first mentioned this in 31 of March 2019
New upcoming Dosbox-SVN Libretro Core

But then the development was in its early stages.

Then again 26 of January 2020
Dosbox-SVN Libretro Core update?

mitu

I see there are 2 (update recently) Libretro cores for Dosbox, besides the older core:

https://github.com/libretro/dosbox-svn (the one mentioned here)
https://github.com/libretro/dosbox-core

Which one will win ?

muldjord

@mitu I hadn't even noticed that one. Interesting. I will test both and see which one works best at the moment.

muldjord

Small update: I've been fiddling with the lr-dosbox-core core today (as mentioned by @mitu). It has some compilation issues which seem to stem from a problem in their repository. It's related to some of the fluidsynth stuff included. But I did manage to get it to compile eventually. Can't get it to run though... So from a pure ease-of-install perspective lr-dosbox-core is subpar. It doesn't even have built instructions or dependencies listed (it requires libsndfile1-dev) in the repository.

EDIT: Little more progress with the lr-dosbox-svn core. My segmentation fault when loading a .conf file stemmed from a mount c ./some/path command. Apparently lr-dosbox-svn does not like .'s in the path even though the dir relative to working dir should be correct (even if it is, it should not crash). It has issues with joystick mapping though. I tried playing Jazz Jackrabbit, and it would not recognize the up-left, up and up-right directions when calibrating the joystick inside the game options.

quicksilver

@muldjord thanks for the progress reports. Since vanilla dosbox isnt up and running quite yet on the pi4 I thought I would try dosbox-sdl2 but it apparently doesn't like .ogg/.mp3 files so some of my CD based games will not work properly. I'll try out lr-dosbox if it looks like youre making some headway.

muldjord

@quicksilver You can try it if you want, just create the script /home/pi/RetroPie-Setup/scriptmodules/libretrocores/lr-dosbox-svn.sh with the following:

#!/usr/bin/env bash                                                                                                                                                                                         

# This file is part of The RetroPie Project                                                                                                                                                                 
#                                                                                                                                                                                                           
# The RetroPie Project is the legal property of its developers, whose names are                                                                                                                             
# too numerous to list here. Please refer to the COPYRIGHT.md file distributed with this source.                                                                                                            
#                                                                                                                                                                                                           
# See the LICENSE.md file at the top-level directory of this distribution and                                                                                                                               
# at https://raw.githubusercontent.com/RetroPie/RetroPie-Setup/master/LICENSE.md                                                                                                                            
#                                                                                                                                                                                                           

rp_module_id="lr-dosbox-svn"
rp_module_desc="DOS emulator"
rp_module_help="ROM Extensions: .bat .com .exe .sh .conf\n\nCopy your DOS games to $ROMDIR/pc"
rp_module_licence="GPL2 https://raw.githubusercontent.com/libretro/dosbox-svn/libretro/COPYING"
rp_module_section="exp"
rp_module_flags=""

function sources_lr-dosbox-svn() {
    gitPullOrClone "$md_build" https://github.com/libretro/dosbox-svn.git libretro
}

function build_lr-dosbox-svn() {
    local params=()
    if isPlatform "arm"; then
        if isPlatform "armv6"; then
            params+="WITH_DYNAREC=oldarm"
        else
            params+="WITH_DYNAREC=arm"
        fi
    fi
    cd libretro
    make clean
    make -j4 "${params[@]}"
    md_ret_require="$md_build/libretro/dosbox_svn_libretro.so"
}

function install_lr-dosbox-svn() {
    md_ret_files=(
        'COPYING'
        'libretro/dosbox_svn_libretro.so'
        'README'
    )
}

function configure_lr-dosbox-svn() {
    mkRomDir "pc"
    ensureSystemretroconfig "pc"

    addEmulator 0 "$md_id" "pc" "$md_inst/dosbox_svn_libretro.so"
    addSystem "pc"
}

Then start the RetroPie setup script from ES, go to experimental packages and install lr-dosbox-svn package from source. That will install the lr-dosbox-svn core and add it to the RetroPie system as usual. There's not much else to it.

quicksilver

@muldjord how is the performance on the pi 4? Lr-dosbox was too slow on my pi 3.

muldjord

@quicksilver Not too good unfortunately. I tried using it with the config that comes with the non-libretro package and it improves it quite a bit. But it's not good even with that. With that said, I have the same issues with the non-libretro package on Pi4. I'm gonna look into why this is and see if I can figure out a way to get it to run better.

EDIT: No luck so far. Maybe this is down to sdl2 still not supporting the videocore. Not sure, I'm not knowledgeable enough to answer that currently. I've been digging up information on the videocore 6 support in the mesa project though. And of course I can't find the article I read it on some days ago, but supposedly the latest release of Raspbian now has the version of mesa that contains it included in the kernel it uses (take this with a grain of salt. The article could have been wrong, and I certainly could have misread it as well). That doesn't mean all software will use it though. For instance, SDL2 will probably need some flags to use it I believe. Again, I'm kind of guessing here, my knowledge is limited on the subject.

ParadoxGBB

I wouldn't count out DosBox ECE (https://dosboxece.yesterplay.net/en/). There's a lot of interest on these forums to get Windows 9x running, and this fork seems better at doing it.

RealNC

@muldjord said in lr-dosbox-svn / lr-dosbox-core (new dosbox libretro cores):

Small update: I've been fiddling with the lr-dosbox-core core today (as mentioned by @mitu). It has some compilation issues which seem to stem from a problem in their repository. It's related to some of the fluidsynth stuff included. But I did manage to get it to compile eventually. Can't get it to run though... So from a pure ease-of-install perspective lr-dosbox-core is subpar. It doesn't even have built instructions or dependencies listed (it requires libsndfile1-dev) in the repository.

I've added some more information about dependencies:

https://github.com/realnc/dosbox-core

Most deps can now be bundled. They can be built together with the core and linked against statically. glib and alsa-lib are not, but I think these are available (and even installed by default) on virtually every Linux system.

muldjord

@RealNC Thank you for the update. I seem to be able to compile it now, but had some weird issues with configuring the fluidsynth lib. Anyways, I'll update you all on this when I have tested it.

RealNC

Sorry for the silly question, but I'm not familiar at all with retropie (or the rpi in general.) Don't the libretro buildbot ARM builds of dosbox-svn run as-is on retropi? I mean these:

http://buildbot.libretro.com/nightly/linux/

mitu

@RealNC They do work (I know I tested the armv7-neon-hf build for dosbox-svn). If the regular dosbox-libretro repository is no longer updated, I guess we can switch to dosbox-svn instead ?

I think the new dosbox-core is the one that's not working - due to the C++17 requirements. It builds, but I think I got a runtime error when loading the core. I can repeat the test to get the actual error.

RealNC

@mitu
In that case, I will look into adding ARM builds for dosbox-core. Right now it's only being built for Linux x86-64.

If you build yourself, then you need to pass STATIC_LIBCXX=1 to make so that libstdc++ and libgcc_s are statically linked. This is already being done for the x86 buildbot builds so that the core runs on old Linux distros as well.

mitu

@RealNC I'll give it a try.

RealNC

I was able to set up a build using Ubuntu 16.04 ARM 32-bit ("armhf"). I have no idea if it runs though, so it would be helpful if anyone could test:

https://github.com/realnc/dosbox-core/releases/download/latest_build/linux-armhf.zip

Munt, fluidsynth and bassmidi are all supported and built-in (except for bassmidi due to licensing) along with their dependencies (like vorbis, libsndfile, etc.) The only external library dependencies are:

libasound.so.2
libpthread.so.0
libgobject-2.0.so.0
libglib-2.0.so.0
libm.so.6
libc.so.6
ld-linux-armhf.so.3

which I believe should be already pre-installed on virtually all Linux systems out there.

mitu

@RealNC said in lr-dosbox-svn / lr-dosbox-core (new dosbox libretro cores):

https://github.com/realnc/dosbox-core/releases/download/latest_build/linux-armhf.zip

Seems to be ok on a PI4 (Raspbian Buster) system, I don't get any errors when starting.

I get a crash though trying to load a simple .conf file, but since the .so doesn't have debugging symbols, kind of difficult to say where it crashes. Could be because I don't have any soundfonts or some assets are missing.

EDIT: Compiling directly on a Raspbian Buster works, but even with STATIC_LIBCXX=1, there's still a runtime error about missing a new C++17 filesystems function. I think that's ok, Buster has only gcc 8.3.0, so it's missing the necessary requirements. Probably if compiled with a newer gcc/clang would work.

RealNC

@mitu said in lr-dosbox-svn / lr-dosbox-core (new dosbox libretro cores):

Seems to be ok on a PI4 (Raspbian Buster) system, I don't get any errors when starting.

I get a crash though trying to load a simple .conf file, but since the .so doesn't have debugging symbols, kind of difficult to say where it crashes. Could be because I don't have any soundfonts or some assets are missing.

It doesn't rely on any assets or soundfonts. I'll put up a debug build as well.

EDIT: Compiling directly on a Raspbian Buster works, but even with STATIC_LIBCXX=1, there's still a runtime error about missing a new C++17 filesystems function. I think that's ok, Buster has only gcc 8.3.0, so it's missing the necessary requirements. Probably if compiled with a newer gcc/clang would work.

Ah, with GCC 8 you need to add -lstdc++fs to LDFLAGS. The handling of that is wonky though. You probably have to edit Makefile.libretro and add in line 366, at the end of the line that starts with LDFLAGS += `$(PKGCONFIG)

RealNC

I uploaded a debug build as well:

https://github.com/realnc/dosbox-core/releases/download/latest_build/linux-armhf-dbg.zip