I am developing an Android application using Unity + ARCore, but I did not find many articles developing on Ubuntu, so I mainly summarized the environment construction. As of this time (2020/12/30), I used the newest versions of Unity and ARCore as much as possible.

Developed app

We have developed an app that puts an object in the place when you tap the screen, which is explained in "Getting Started ARCore in Sapporo". However, the version of ARCore used in this article is a little old, so I changed it to the latest version.

environment

--Development machine

Ubuntu 16.04
Unity Hub v2.0.0
Unity 2019.4.17f1 (LTS)
ARCore v1.22.0 Download link
Gradle v5.6.4 --Verification device
- Xperia 5 (J9210)

Development environment construction

I will not explain in detail how to install Unity on Ubuntu because there are other commentary articles.

Unity installation

Download Unity Hub from the Download Page (https://unity3d.com/jp/get-unity/download)
Select "*** Click here for Unity Hub details ***"
Find and select "*** Unity Unity Hub v2.0.0 Release ***"
Select "*** Hub for Linux ***" from ** Download Link ** to download
A file called * UnityHub.AppImage * will be downloaded
Grant execute permission $ chmod + x UnityHub.AppImage
Run Unity Hub $ ./UnityHub.AppImage
Install Unity
Select "Install" from the menu on the left and select the "Install" button on the upper right
Unity 2019.4.17f1 (LTS)
Add "*** Android Build Support ***" in the plugin to download

After waiting for a while, the installation is completed.

ARCore installation

Installation of required packages Select "Window-> Package Manager" and install the following packages
- Multiplayer HLAPI
- XR Legacy Input Helper
Download the package from "here" (https://github.com/google-ar/arcore-unity-sdk/releases/tag/v1.22.0) arcore-unity-sdk-1.22.0.unitypackage
After opening the Unity project, add the package
Select "Assets-> Import Package-> Custom Package"
Select the * arcole-unity-sdk-1.22.0.unitypackage * downloaded above

Gradle installation

Gradle will also be installed if you add * Android Build Support * when installing Unity, but ARCore requires version 5.6.4 or higher. In my environment, the version of Gradle installed by default is older than this and I got a build error, so I installed it additionally. I installed * version 5.6.4 *.

Download Gradle
Find v5.6.4 from "this page" and select * complete * under * Downlowd *
A file called ** gradle-5.6.4-all.zip ** will be downloaded
Move and extract files
Download and move the file to any directory. I moved to the same directory that contains the Gradle that Unity downloaded $ mv gradle-5.6.4-all.zip ~/Unity/Hub/Editor/2019.4.17f1/Editor/Data/PlaybackEngines/AndroidPlayer/Tools
Deployment $ unzip gradle-5.6.4-all.zip

Unity build settings

There are other articles that explain in detail here as well, so I will describe them briefly. The following are the settings in the Unity project.

--Change Platform to Android -* File-> Build Settings , select "Android" and press "Switch Platform" --Gradle path setting - Edit-> Preferences-> External Tools-> Android-> Gradle *, uncheck Recommended and select the additionally installed Gradle folder. (For my environment): / home/{user}/Unity/Hub/Editor/2019.4.17f1/Editor/Data/PlaybackEngines/AndroidPlayer/Tools/gradle-5.6.4 --Player settings

Edit - > Player Settings -> Player
- Other Settings --Removed Vulkan from Graphics API --Minimum API Level 7.0 or higher
- XR Settings --Check ARCore Supported
- Publishing Settings --Check Custom Main Gradle Template --Check Custom Launcher Gradle Template

Android device recognition

The following settings are required to connect the Android device to Ubuntu and install the app. First connect your Android device to your PC and then run the lsusb command to verify your vendor ID

$ lsusb
Bus 001 Device 015: ID 0fce:520a Sony Ericsson Mobile Communications AB

When multiple USB devices are connected to the PC, the number of results will be output. Look for your Android device in it. At the end of the line is the manufacturer's name, which you can see. The above is the result when Xperia 5 is connected in my environment. * 0fce * in this is the vendor ID. Use this value to add a device connection rule.

$ sudo vi /etc/udev/rules.d/51-android.rules
#Write the following in a file. Vendor ID changes according to the environment
UBSYSTEM=="usb", ATTR{idVendor}=="0fce", MODE="0666", GROUP="plugdev"

App implementation

The contents of P.50 ~ P.88 of "Getting Started ARCore in Sapporo" have been implemented almost as they are, but only the following changes have been made according to the ARCore version.