I sure am playing a lot of space pew pew over the last months. Took a lot of screenshots too and it’s kinda hard not to drown my timeline with screenshots every day. Today I sifted through the pile and found a bunch I’d like to share (some again) so here is a little gallery of (mostly) space simulation games I play on my Linux PC. And I’ll keep making that point until I can browse the web without getting daily reminders by random strangers claiming that gaming on Linux PC is not possible. Cuz it is.

This I play mostly under Proton with the Primary Buffer Panel whenever possible. It’s just the most fun this way (kids love it too).

The more recent X series have native Linux builds but work also perfectly fine with Wine.

Both run via Lutris and with Proton-GE and usually with my DIY Headtracker.

FlightGear runs native on Linux and Fly Dangerous does have a native Linux build but due to an issue with terrain generation being single threaded I use Proton for this one too until this is solved. No Man’s Sky runs perfectly with Proton.

I play all of the above with my X52 Pro H.O.T.A.S. and some with my DIY headtracker stretched over three displays in a so called multihead setup. Let me know if you’ve any questions how this can be set up.

Okay, recap from the last making session of the button box for my . What I achieved this time: The LCD controller has now a place inside the contraption while the LCD controller buttons are screwed on the outside. This is mostly because I have no buttons laying around to be used instead. I did note down the pin-out of the connector though so I can change this any time. It has a funny LED though that has 3 pins, GND, Red and Green. Uncertain what to make of this.

The button box itself was put on stilts for the extra room required. The LCD itself is prepared to be added to the button box but I’ve to remove part of the former hinges because they are way too sturdy to be removed with a simple cutter knife. I’ll probably need a grinder or a saw and that’s work I will not do at my computer but in the basement.

Next was preparing the ICP in the centre. For this I created a new box of cardboard that is attached to the button box with tape that also acts as a hinge so I can “open” it to work on the switches that go there. I also noticed that my knobs for the rotary encoders or potentiometer are way too big. I could compensate this with more height but I don’t want the ICP to dwarf the button box itself 🤔 So… mebbe I’ll use smaller knobs. On the topic of knobs: Dem, the costs for decent sized knobs are insane. Like ~8 EUR for one knob! So… perhaps I’ll go for spray painted wood here. I don’t know yet 🤷

Yeah, and I got tired of calling it just “button box”. It’s not. It’s a “glorified button box mock-up with a gorram LCD made from cardboard”. So I decided that it needs a name and as a nerd I came up with… Primary Buffer Panel! Firefly fans will know. Others may educate themselves via https://www.youtube.com/watch?v=mY59BYSrxn0 and have a laugh.

It’s also a running gag in the family. My van tended to loose all kind of parts while driving and when Serenity aired my dad yelled at this very specific scene: “Hah, just like your car!” 🤣

I track my working hours with timewarrior. That’s a CLI program that has a lot of nifty features and can also be hobbled together with taskwarrior to automated time tracking when a task is started. The taskwarrior on the other hand gets my todo list from various bugtrackers as sources, like Redmine and Jira, using bugwarrior-pull.

With this set-up I’ve my to-dos and my tracked hours available on the terminal, where I spend most of the day anyway. This is more or less comfortable for me but there is a huge drawback.

At the end of the months I’ll need some numbers and as it goes each company or customer has it’s own time tracking system (or even wants a csv export!) so I’ve to backfill the real systems each month. That’s a very tedious work especially if time has to be logged on specific tickets or customers and booking is done with quarter hours so I’ve to do some quick math in my head all the time.

In theory timewarrior has me covered on this because it has a summary view that is basically fine but this can not be used to grepped or sorted for certain tickets because it displays the date for each day only once.

Another nifty feature is the timewarrior export function that results in a JSON. The result is somewhat limited though since it will for example not display and durations and there is as far as I know no way to change this.

Demo how the various views or exports of timewarrior look (And yes, not _everything_ I work on is tracked here :P)

This is where jq (a lightweight and flexible command-line JSON processor) comes in. This little tool is seriously underrated and it allows me to change the format and the values of the JSON export on the fly by calculating for example time durations on the fly, reformats start and end dates so import functions of table calculation programs, like LibreCalc, can read the values as date (we all know that Excel reads anything as date already) and displays me the tracked time in quarter hours for each entry so it’s for most cases a no brainer now to backfill another time tracking system with this. The result can also be easily sorted now to find for example times for a specific ticket by grepping for it’s id.

timew export :week | jq -r '["id", "start", "end", "duration", "quarter_hours", "description"], 
    (.[] | 
        # make sure .end is set (may be empty for currently active tracked time)
        .end = (.end // (now | strftime("%Y%m%dT%H%M%SZ"))) |
        .duration = ( (.end | strptime("%Y%m%dT%H%M%SZ") | mktime) - (.start | strptime("%Y%m%dT%H%M%SZ") | mktime) ) |
        # round duration to quarter hours
        .quarter_hours = (.duration / 3600 / 0.25 | ceil*0.25) |
        [
            .id,
            # urks, localtimes are a mess in jq, ymmv - as long as it is consistent off I do not care tho
            (.start | strptime("%Y%m%dT%H%M%SZ") | mktime | todateiso8601), 
            (.end | strptime("%Y%m%dT%H%M%SZ") | mktime | todateiso8601), 
            (.duration | strftime("%T")),
            .quarter_hours,
            (.tags | join(", "))
        ]
    ) |
    @csv'

The resulting csv file can be imported into most table calculation software now or read manually in a more comfortable way.

Timezones are still an issue. There are so many open tickets on jq on this that I don’t even bother.

Ymmv, as usual 🙂

I somehow never finished this little gem and since I feel somewhat nostalgic today decided to give it another spin. Interestingly this game was ported to various systems including Mac and Linux in 2013 premiering as part of the Humble Double Fine Bundle. This is probably also where I picked it up.

Anyway, uploading this will take some time but you can watch the partially muted recording elsewhere. Won’t upload it here thanks to ridiculous copyright claims.

Diaspora: Shattered Armistice, still awesome today: http://diaspora.hard-light.net/

Video of Diaspora: Shattered Armistice (on Linux PC)

Seems to work nice with my DIY headtracker on Linux PC too. Sadly I got quite some frame-drops due to recording (and probably multi-head too). It works way better without all the cameras and a life-stream going on but I think it’s enough to get a good impression. Botched emergency landing included xD

Warning: This may fuel a desire to re-watch the BSG series again 😀

I like space and science fiction. Diving into epic stories set in some distant future amazes me since elementary school.

I’m also a gamer. And a tinkerer. It’s in the family.

I keep wondering: How can I improve the immersion of my games without going full VR?

DIY Headtracker for gaming (on Linux PC)

I used a triple screen set-up before. It consisted of different models in height and size. When one screen finally broke down I purchased 3 refurbished screens of the same brand and model. What a difference!

The kids love it too. Of course. Means less stick time for me. Anyway.

This is when I started to read about head tracking and went on a quest to get this working for the game X4. As a bonus on Linux PC, my preferred system also for gaming.

The thing is: “The” reference product for a headtracker is the TrackIR system. Price as of today: 220 EUR. Ouch! That’s like a cheap VR, right? And it’s Windows only. No thanks.

So I checked what’s in this thing. Apparently a cheap camera, some infra-red LED, and a filter allowing only infra-red waves. And software, of course.

Since this is for Linux I get to pick my poison for the software part, and I settled with Opentrack fast. Onwards to the hardware part. I abused my mobile phone for the testing, sending it’s Gyroscope data via wifi to my PC, and while it worked it also _sucked_. Both, phone and wifi I mean.

Head tracking is awesome. And I knew I want it. So I started prototyping. For this I went with a simple design that I eventually implemented on cardboard. It looks hilarious but it gets the job done.

The focus was on a long life cycle so I wouldn’t have to replace the rechargables in the middle of a session. To get this right I checked with the camera that I was going to use. See (video above), this is way to bright and by trying various resistors I could get this down to 33mA per LED and still get a decent detection rate with Opentrack.

Speaking about the camera. That’s nothing special. It’s a dead cheap 480p Logitech QuickCam Communicate STX that I got from a discounter a decade ago. It was so cheap it doesn’t even _have_ an infra-red filter that I’d have to remove first.

I used tape to attach the salvaged camera cover of a dead G20 controller. That’s a Wii Remote knock-off that does basically the same thing like a headtracker. Various other foils can be used for this as well, as long as they permit infra-red. The idea is to reduce or remove all other light waves but infra-red.

The trick is to also turn off auto exposure and fiddle with the contrast and sharpness until a decent frame rate and a clear infra-red wave source by the LED can be seen.

When I was satisfied with my meter readouts, and my highly professional scribbles, I started working on the prototype while streaming the whole process on the Discord channel of the awesome Fly Dangerous project. If you like racing with a space ship give it a shot.

The prototype is made of cardboard that doubles as isolation for the polarity. The rest is tape and hook-and-loop fastener to attach the headtracker to my headphones. No magic here. The whole contraption is powered by two 1.2V rechargeables. I opted for a micro switch and an additional LED as power indicator, that I dimmed down even more. I can after all not see infra-red so this seemed like a good idea to me. Spoiler: It is.

So how does it play? Over the next weeks I tried basically any game supporting head tracking that I could get my hands on. Please keep in mind that I usually play with lights off but started the studio lights for demo purposes. The tracker does still work just fine.

I quickly found out that each game needs it’s own profile for fine tuned settings. Good thing that Opentrack has me covered on this. First, my beloved X4 using Wine and the TrackIR protocol.

Sadly I came to the conclusion that my GPU is no longer up for the task and Wine would cost me too many frames. I switched Opentrack to emulate a joystick instead and mapped it to camera movements in the native X4 version. It’s not exactly the same but it’s okay-ish. I have an idea how to hack this properly into X4 using an extension and a UDP server but that’s a topic for another day.

Anyway, the same principle works with X Rebirth too, making me even happier. While dated it still has it’s charm and the verse still feels a lot more alive compared to X4. It’s also not taxing my GPU that much.

Now for something different. When Opentrack would list a “protocol” named FlightGear I became very curious. I installed this free and open source flight simulator and crashed my first Cessna into the ground minutes later. By now I’m confident that I can crash a Cessna just about anywhere. I’m not fond of flying in real-life but avionics sure are a fascinating topic.

This was the moment a Steam sale happened and I bagged various flight sims, Space Kerbal and House Of The Dying Sun. All with TrackIR support.

Little did I know what gem I bagged with House Of The Dying Sun by the way. Sadly it’s also very short but I enjoyed every minute of it and will probably play it again. The art, sound and music reminds me a lot of Battlestar Galactica. Easy win 😀

So yeah, this is my current gaming set-up. I built myself a head tracker for 5 EUR. On Linux PC.

I also may have fallen into the rabbit hole called “simpit”.

Racing in space sims is a thing and usually done by a small and sometimes hidden community within games like Elite Dangerous or Star Citizen. What happens when this is not enough for players, or when they simply don’t want to waste time grinding the required resources in-game, is demonstrated by @jayleefaulkner at https://github.com/jukibom/FlyDangerous

I was delighted to find Linux PC binaries over at https://jukibom.itch.io/fly-dangerous as well – and this is a very early alpha even. Guess someone pestered the dev about Linux already and I so had to give this a spin, of course.

Unpacking the FlyDangerous-0.2.2b-linux.zip was a no brainer and the game itself started just fine. I do have however a very specific triple head display setup and the game started on the wrong display in fullscreen mode and could not be persuaded to go into windowed mode so I could reach the buttons to change the display resolution via hotkey or tweak the config at ~/.config/unity3d/StarGoat/FlyDangerous/prefs. It insisted of staying on defaults so once more wmctrl to my aid:

wmctrl -x -r FlyDangerous -b remove,fullscreen
wmctrl -x -r FlyDangerous -e 0,0,0,5760,1200

Yes… this will do!

Fly Dangerous in all it’s glory over multiple screens

After this was sorted out I noticed that Unity detected “some” joystick with only an X and an Y axes. This doesn’t do my X52 Professional H.O.T.A.S justice. Usually I’d use the controller mapping in Steam now but this isn’t a Steam game and while it can be added as a foreign game to Steam I can not set any controller configs for it there so I started looking around.

Apparently (modern) Unity uses SDL2 and the modern evdev input system to detect joysticks on Linux PC and this can be indirectly configured / overridden using the environment variable SDL_GAMECONTROLLERCONFIG to provide additional input configurations like the ones listed in https://github.com/libsdl-org/SDL/blob/main/src/joystick/SDL_gamecontrollerdb.h (that somehow does not know of the X52 H.O.T.A.S?). Luckily there are various tools to create a mapping for this – for example Gamepad Tool at https://generalarcade.com/gamepadtool/ – which sure looks familiar enough from the re-mapping I’m used to by… Steam! AntiMicroX should also work for this but I didn’t try.

Gamepad Tool with my configured X52 Pro for Fly Dangerous

And since I’m on Linux and totally lazy I threw all this in the script file flydangerous.sh to start the game:

SDL_GAMECONTROLLERCONFIG="03000000a30600006207000011010000,Logitech X52 Professional H.O.T.A.S.,a:b30,b:b3,x:b4,y:b1,back:b33,guide:b31,start:b32,leftstick:b9,rightstick:b11,leftshoulder:b26,rightshoulder:b24,dpup:h0.1,dpdown:h0.4,dpleft:h0.8,dpright:h0.2,leftx:a5,lefty:a2,rightx:a0,righty:a1,lefttrigger:b23,righttrigger:b25,platform:Linux," ./flydangerous.x86_64 &
sleep 2
wmctrl -x -r FlyDangerous -b remove,fullscreen
wmctrl -x -r FlyDangerous -e 0,0,0,5760,1200

What to say – Fly Dangerous sure hits a nerve here and I wonder what more is to come.

At least gaming itself is easy as pie on Linux in 2021. Very very very early indie and alpha version games? Not so much 😉

I love gaming over multiple monitors. It’s my current choice for work and games – especially simulations. Having several monitors attached to one computer (or graphic card) is not a big deal in 2021 any more. The framebuffer in recent graphic cards is insanely huge compared to some years ago, when one really had to think twice about the possible resolution when e.g. connecting a beamer to a laptop (good old SiS 630 anyone?).

xfce4-display-settings for my refurbished “new” set of displays

This couldn’t be easier nowadays. Even mixing the integrated graphic card of a recent Intel CPU with an NVIDIA or AMD dedicated graphic card does usually “just work”. Some driver specific mode may have to be set but that’s it. The workspace easily expands over multiple displays and windows can be moved around freely.

Games do not see one huge desktop but individual displays

There is however a catch. Games tend to read the primary display only and the maximum resolution offered usually comes with the readout of this very first display – or worse – the first display connected. This sucks especially when the monitors have different resolutions, as it was the case for me for several years now, because I didn’t just purchase a set but collected discarded monitors over the time. This can often be omitted by temporary disabling the “false” ones or by force window mode.

This results in hacky scripts involving xrandr, wmctrl and xdotool. This is for example how I hammered X4: Foundations into shape _after_ it started, because it would allow me to select a single display only. Set to window mode it can be freely scaled but that comes with a disturbing window decorations so with this the X4 window gets positioned to 0x0, expanded to 5770×1210 and the window decorations purged:

xdotool search --class "X4" windowmove --sync %@ 0 0 windowsize %@ 5770 1210 set_window --overrideredirect 1 %@
X4: Foundations on Extreme Multihead

That’s a pain to find out and the fun really stops when it comes to Proton or some games that would not allow resizing over their maximum detected resolution – like for example Everspace.

How about a virtual monitor?

So the idea was to introduce a completely virtual monitor to the systems with the resolution of choice. VNC servers do that all the time so it must be possible. The usual approach won’t work in this case though: When loading the dummy driver the real displays can usually no longer be used and the drivers for AMD and NVIDIA do not really offer such a feature at all.

It is perfectly possible to define virtual monitors with a recent xrand but they have to be mapped on an existing output (a real port). One can use an unused port (as in: no monitor connected) for this, add a Modeline and even force it as “online” like so: echo on > /sys/kernel/debug/dri/0/HDMI-A-1/force

I was delighted to see the display showing up briefly but the AMD driver made short work of my soaring hopes by forcing it off again in an instant. So close and yet so far. This would require some hardware hacking by creating a dummy plug for the port. That’s basically some resistors in the right place making the computer think a display is connected. I hear they can also be purchased and this may be a way for others.

Others seem to have had success by compiling the experimental DisplayLink driver that seems to offer (virtual) monitors but I really didn’t feel like fiddling with something even more alien that will probably break on the next kernel update again.

Intel to my aid!

The success for me was in the end to use of the Intel driver and it’s VirtualHeads feature. The caveat is that one probably needs an Intel CPU for this to work and has to create a X11 config file. If this is done without adding the usual driver people will experience black screens on reboot only. This may be a show stopper for inexperienced Linux users who don’t know how to recover from a broken X11 config (yet :D). For me this is an amdgpu so my file /etc/X11/xorg.conf.d/20-intel-virtual-and-amd.conf has to look like this:

Section "Device"
       Identifier "amdgpu0"
       Driver "amdgpu"
Endsection

Section "Device"
       Identifier "IntelVirtual0"
       Driver     "intel"
       Option     "VirtualHeads" "1" 
EndSection

Triple check that your driver is used in there instead or you will end up with a broken config without the possibility to log in to a graphical window manager. When in doubt start e.g. a new session to your liking on the next display server where you can switch back with the key combination ctrl+alt+F[1-0]: startx /usr/bin/startxfce4 :2

Once started a new provider shows up and the new output “VIRTUAL1” is available: xrandr --listproviders

Providers: number : 2
Provider 0: id: 0x59 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 4 associated providers: 1 name:AMD Radeon RX 5600 XT @ pci:0000:03:00.0
Provider 1: id: 0x9e cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 5 outputs: 4 associated providers: 1 name:Intel

Configuring the virtual monitor with xrandr

Now that we have a virtual monitor we need a Modeline for it. This is usually the current screen (of the framebuffer) and can be calculated (e.g. sum of all monitors x height and Hz of one monitor) or by asking the system: xrandr | grep Screen

gtf (or cvt) helps obtaining the Modeline: gtf 5760 1200 60

  # 5760x1200 @ 60.00 Hz (GTF) hsync: 74.52 kHz; pclk: 579.47 MHz
  Modeline "5760x1200_60.00"  579.47  5760 6144 6768 7776  1200 1201 1204 1242  -HSync +Vsync

Now all information needed to finally set up the virtual display is there. I’m creating the virtual display on top of the three real displays because I also want to see what’s drawn on it. That’s not strictly required though and in fact most graphical tools to configure the monitor location will even refuse this – because this use case is simply not considered or supported. Gnome for example really didn’t like this. XFCE4 didn’t care. Ymmv:

xrandr --newmode "5760x1200_60.00"  579.47  5760 6144 6768 7776  1200 1201 1204 1242  -HSync +Vsync
xrandr --addmode VIRTUAL1 "5760x1200_60.00"
xrandr --setmonitor Virtual 5760/1554x1200/324+0+0 VIRTUAL1 
xrandr --output VIRTUAL1 --mode "5760x1200_60.00" --pos 0x0 --primary

It’s done.

The virtual monitor becomes visible in display settings (xfce4-display-settings here)

And it works!

After a lot of research and fiddling (and breaking my X config several times) I finally found a working solution. Games let me select the virtual monitor or see at least my primary with my “maximum” resolution. Sometimes this still requires window mode but I could care less – the decorations are optional. And it works like a charm! Here is a small selection of the games I play most at the moment:

This is how my set-up looks:

Now I’ve another problem. With this my usual 1080p gaming resolution is no longer and my graphic card is simply not up for the job any more 🤣

At least gaming itself is easy as pie on Linux in 2021. Complex display set-ups? Not so much.