Configuration ideas and files to optimize gaming with dosbox and RetroPie
This repository is a collector for dosbox configuration on RetroPie for those features:
- Separate persistant DOS application/data from non-persistant data (aka sandboxing)
- Collect config files for popolar DOS games which are compatible with the sandbox concept and will find media with help of Skyscraper[1].
- Collect joystick mapper files for games which didn't provide joystick support in those old days
- Changed RetroPie scripts for better doxbox integration
I like to show my kids how cool old games from by childhood were! I often impress them because I played the inital first version of a popular todays Android game.
This chapter explains in principle how to reach this goal.
After some proof of concept implementations the design decision goes for Linux OverlayFS feature. This feature consists of logic overlaying two folders ("lowerdir" and "upperdir") to a new directory ("workdir"). The mapping for DOSBox sandboxing is as following:
- lowerdir = Initial installed/configured DOS game
- upperdir = Empty in the beginning and filled with all dynamic application changes
- workdir = An overlay combination of lowerdir and upperdir
This software design allows a flexible solution to the problem that DOS games tend to write their configuration or save games directly into their application data folder. The idea is one copies a fresh installed DOS game to the "lowerdir" and it could be easy reset to the install state by removing the "upperdir". Those aplication features could be realized later:
- Automatic remove "upperdir" files after game exists => always start clean
- Support different "upperdir" sets and so allow some sort of game configurations (e.g. different users or patch sets)
- Easy reset to initial state after you or the game itself messed up everything
Example /etc/fstab extension:
- overlay /media/TVStation/RetroPie/roms/pcdata/overlay overlay noauto,x-systemd.automount,lowerdir=/media/TVStation/RetroPie/roms/pcdata/base,upperdir=/media/TVStation/RetroPie/roms/pcdata/changes,workdir=/media/TVStation/RetroPie/roms/pcdata/tmp 0 0
(Path setup fits to by local installation with external harddisk; this needs to be explained in detail)
As this OverlayFS design solution is very stable and efficient as directly supported by the Linux kernel this is a drawback for everyone not using Linux. So this complete featue described in this repository works only with Linux (special: RaspberryPI / RetroPie).
Just a DOSBox game file collection that supports the sandboxing feature and is compatible with SkyScraper[1] media scrapping. All files share some generic path concept and work only in the context of this configuration. Here is very important to add that this includes for sure only the startup configuration and no media or foreign properties. Many DOSBox games which you find somewhere in the internet contains startup config files, but they often need to be adopted to your local setup. This collection is optimized for RetorPie[3] with standalone dosbox (not lr-dosbox). See folder "pc".
Some (old) games need adaption to the keyboard mapper to create some more fun playing them. Some are collected here and referenced from the local game specific DOSBox configuration file.
Unfortainly I had not much success getting lr-dosbox to run with the same performance as standalone dosbox. So some (dirty) workaround (setting HDMI resultion direct) are made to get the screen resultion working for most games. Solving this problem with libretro integration or a intermediate DOSBox configuration tool (including the sandboxing support) would additional help to ease the usage.
See folder "runcommand" for start/stop scripts that uses tvservice[4] tool. Maybe you need to install this tool with the RetroPie installer.
A better solution could be to implement a generic solution in /opt/retropie/supplementary/runcommand/runcommand.sh and provide back to RetroPie.
See dosbox/dosbox-SVN.conf for an example what has to be changed. The changes in chapter [sdl] are needed to fit with the resolution set by tvservice from runcommand. The changes in chapter [autoexec] have to fit with your local path setup and fstab OverlayFS configuration.
- Explain all modified and created files to this repositiory
- Do the software detail design
- Provide easy file setup and user howto
[1] https://github.com/muldjord/skyscraper
[2] https://www.kernel.org/doc/html/latest/filesystems/overlayfs.html
[3] https://github.com/RetroPie
[4] https://www.raspberrypi.org/documentation/raspbian/applications/tvservice.md