12 min read

I had a plan. I wanted to get the original EyeSkills Community edition back up and running for Christmas. I wanted to integrate the changes I’d been making over the last months. Working on the software really isn’t a priority at the moment (getting the eye tracking hardware ready is more important, without which we’re “flying blind”) but nevertheless…


Nothing has been working out the way I planned. It’s been a litany of blockers. The people we’ve been working with to get our custom eye tracking hardware have delayed the project for a couple of months… just as my Macbook died forcing me to get a new machine a few weeks ago. When my Macbook died, I decided that it was time for a breath of fresh air so I did something I have repeatedly been burnt doing before, and got a regular laptop to run Linux. As it happens, after less pain and suffering than I expected, everything’s working better than I expected with a stock Ubuntu (for Unity compatibility). Then it was time to install Unity.

Well, let the pain commence. I’ll keep up dating this as I go for others in the same boat.

Installing Unity 2019.2.17f1 on Ubuntu 19.10

Immediately, we have blank compilation errors in Unity. Looking in the Editor.log hidden away in ~/.config/unity3d/” there’s a whiff of a clue that this is caused by :

-----CompilerOutput:-stdout--exitcode: 134--compilationhadfailure: True--outfile: Temp/UnityEngine.TestRunner.dll<br> -----CompilerOutput:-stderr----------<br> No usable version of the libssl was found

…which implies I either have to downgrade ssl from 1.1.1 to 1.0.0 or find some way to get two simultaneous installations happily co-existing (and Unity knowing which to use). This could take time.

UPDATE: Seems to be working out ok to install a version of libssl1.0.0 – it exists, but doesn’t seem to be used by the system by default ‘m guessing the first set of blank compiler errors are:

wget http://archive.ubuntu.com/ubuntu/pool/main/o/openssl1.0/libssl1.0.0_1.0.2n-1ubuntu6_amd64.deb<br> sudo dpkg -i libssl1.0.0_1.0.2n-1ubuntu6_amd64.deb

After that the next issues awaits: “Unspecified error during import of AudioClip”… I’ve tried

sudo apt install lib32stdc++6 -y

but that’s only going to be the beginning of the battle…

UPDATE : After a restart, that problem went away. I suspect installing lib32stdc++6 did the job, but Unity just needed to the restart to recognise that it existed.

Now I have straightforward “missing namespace” issues – which probably require me to specify some csharp assemblies. We’ll see…

Well, I shall try to keep plodding on while I focus on how to make sure that when this project really gets going again, it’ll really be setup to generate the cycle of rapid feedback and evidence that will speed the creation of approaches that really work.

If you are also in the world of pain that is Unity + Ubuntu 19.10+, I’d love it if you got in touch 🙂

Merry Christmas!


So, the next step is probably to get Visual Studio Code (VSC) working. Why not Atom/Sublime/OtherFlavourOfTheMonthEditor? Getting anything working reliably in Unity is hard enough without wondering far from the tree. The ability to debug running apps on the phone has been exceptionally useful when I was working on OSX with VSC so let’s try to set it up here.

The most hopeful looking instructions I’ve found so far are here : https://stackoverflow.com/questions/52807397/how-do-i-use-visual-studio-code-to-develop-unity3d-projects-in-ubuntu and here https://medium.com/@sami1592/set-up-visual-studio-code-for-unity-in-linux-69b7f4352e0b

These instructions are a bit out of date so here’s an overview of the steps I took :

In VCE view the installed extensions (Ctrl+Shift+X) and add the C# and Debugger for Unity. It might be interesting to take a look at “Unity Game Dev Bundle” as well. You will want to have VCE also create a launch.json from the debug pane, so that you can then start the debugger for unity (use the green arrow).

Close VCE and in Unity set the default editor in the preferences to be /snap/bin/code

All of this works nicely for a fresh, small project, but it appears that it doesn’t work for the EyeSkills community edition because something is broken in VCE regarding multi-projects (i.e. we have some Unity Tests inside ours). Another hour spent getting a step closer to a working setup.

I think the next step is to install a sample project like this https://learn.unity.com/project/tower-defense-template?signup=true and check I can get the whole thing running, before I start to retrofit everything from EyeSkills into a fresh project…. and that seems to work well. So far so good. Does deployment to the phone work?

No. ”

UnityException: Android SDK not found
“. That should just be a question of : ”
sudo apt install android-sdk
“. Just setting up these environments must have already cost 3-4Gb of space. Well, I don’t seem to be able to run the sdkmanager which I would have imagined to have been installed with the android-sdk. The sdkmanager is important for managing which version of Android your Unity builds can support – and I really don’t want to install all of Android Studio just to manage a few SDK installations.

Running ”

apt-file list android-sdk
” shows me that the included tools are in /usr/lib/android-sdk/tools. These tools do not include the sdkmanager 🙁 It looks like the android sdk command line tool are available here : https://developer.android.com/studio, specifically,
<a href="https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip">https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip</a>

We can get it with

wget <a href="https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip">https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip</a>
and then unzip it. I’m going to dump the contents of the resulting tools directory into
with an “rsync -rv /.tools/ /usr/lib/android-sdk/tools/” and hope for the best that this doesn’t cause additional problems. Ah, no, that was a mistake. They are my own user tools, and should live in my own home directory with myself as owner. Undo. Repeat. Oh no. It looks like it’s a Java version problem. Could it be that it won’t run on the version of Java that’s installed by default (11) but requires the old open java version 8?!?

This is where I start to feel really queezy. ”

sudo apt install openjdk-8-jdk
“. What exactly is that going to do? How well will it manage two versions of java co-existing? How will programs select between them? Well, it turns out that it doesn’t. I really, really, want to run Unity in some sort of containerized fashion at arms length behind a cordon sanitaire – but it’s one of the most resource intensive applications I will be running so I want it running close to the metal. It’s like DLL hell, do I sacrifice the modern install of Java just to get Unity working?

It turns out there is a little command called

update-java-alternatives --list
. You can select the version you want to use at a particular moment, so when we run the sdkmanager let’s try to first run “sudo update-java-alternatives -s java-1.8.0-openjdk-amd64”. This breaks a few things in mozilla’s Firefox, but the sdkmanager then works. Now I need to figure out where to position the unpacked tools, and how to hook them into the environment properly…. plus, just to add salt into the wounds, my installation of android-sdk seems to have become broken through something I’ve done thus far (symlinks in /usr/bin to tools like adb are broken as the platform dir is now missing from /usr/lib/android-sdk/tools). Honestly. It’s time to remove the apt package from android-sdk and start again from scratch there, perhaps taking a different path.

After removing and purging the apt package for the android-sdk by way of napalm I discovered that there are two sub-boxes in the Unity Hub’s module installer:

Seriously, how is anybody supposed to know?!? The Android Build Support box was ticked already. You’d think that would mean it would install all child options, otherwise it might show a “-” rather than a tick. I could cry sometimes. Before Unity has even managed to download the SDK/NDK/JDK I can already see problems ahead : https://issuetracker.unity3d.com/issues/ubuntu-unable-to-use-andriod-ndk-and-sdk-tool-installed-via-hub

Yep. What a surprise. Everything is now installed correctly according to Unity:

…unfortunately, trying to build their tutorial project results in :

Why is it always like this with Unity?! I literally needed the last six months to let the frustration of using Unity for this project over the course of 2018 wash out of my bones, and now it’s back again. It’s like trauma. It’s giving me PTSD and a desire to throttle somebody. Calm. Breath. Just another another another obstacle to climb over.

I have tried :

chmod +x Editor/Data/PlaybackEngines/AndroidPlayer/OpenJDK/jre/bin/*<br>chmod +x Editor/Data/PlaybackEngines/AndroidPlayer/OpenJDK/bin/*

That may or may not have changed something, but nothing that I notice.

In ~/.config/unity3d/Editor.log I can see a bit more detail:

Android PostProcess task “Detect Java Development Kit (JDK)” took 64.3625 ms
UnityException: Android SDK not found
Unable to locate Android SDK.

At least we know it’s finding the JDK. So, why not the SDK? As I currently understand it, Unity has installed everything in a self-contained manner. The SDK is in ~/Applications/UnityEditors/2019.2.17f1/Editor/Data/PlaybackEngines/AndroidPlayer/SDK. I don’t think that’s bad, and would approve – if it worked.

The aforementioned issue on the Unity lists points out that the “tools” directory is missing from …Editor/Data/PlaybackEngines/AndroidPlayer/SDK, and indeed it is. Let’s try once more to unzip a copy of the sdk tools and plonk them in there. Wow! It looks like the SDK is discovered by Unity, now it’s just complaining about an inadequate API level for VR (needs to be a minimum of 19 – check in Player Settings in the Unity IDE).

It’s a big compilation job… and my new shiny XPS 7150 is struggling. The CPU is stepping down continually as it gets hot enough to boil an egg… that’ll be another area for improvement, voltage limiting the CPU.

lscpu | grep MHz | awk ‘{print }’ – a nice way to monitor your CPU speed
My CPU is on fire!

Every 1,0s: lscpu | grep MHz | awk ‘{print }’ ben-XPS-15-7590: Sat Dec 28 20:24:19 2019

CPU MHz: 3252.126
CPU max MHz: 4500,0000
CPU min MHz: 800,0000

IT BUILT! Now lets’s try “Build and Run”! Oh, I’m looking forward to this so much. It’ll finally work and deploy straight to my phone! 😀

By this point, are you surprised? I’m regarding this as an inevitability. It looks, at first glance, like Unity has suddenly decided that I’m running windows, rather than Linux.

Every. Single. Step. Forward. Must. Be. Paid. For. In. Pain.

For starters, everything in the Unity installed SDK/platform-tools directory has permissions that prevent execution. Really?!? Let’s try “chmod +x *”. That seems to get us another step further forward. I then needed to setup developer mode on my new phone, whereupon I got… dadada….


Will this ever end? Let’s hope this is going to be simple and do what it suggests. I guess it means this?!?

FINALLY!!! The .apk is deploying to my phone, and is playable.

Now that is working it’ll be time to check that the setup can handle a basic VR game from https://blogs.unity3d.com/2015/12/09/get-started-with-vr-sample-pack-learning-articles/

If THAT works (which at this point really shouldn’t be impossible) it’ll be the right move to take a bit more care to setup a Continuous Integration process and streamline a few things to help development, before pushing on with “retro-fitting” eyeskills. I think I’ll carry on the next steps in another post on another day.

Would you like to beta test EyeSkills* or just follow what we are doing?