Resolved AR Foundation (Android) black screen on first launch bug (IL2CPP)

Hello, I'm having issues after swapping from Mono backend to IL2CPP backend I'm finding the app prompts camera permissions but after allowing the screen stays black, if the app is closed and re-opened it then works fine, how can I remedy this so the camera works first time? (Problem doesn't occur with Mono backend)

Thanks.

 

This used to be a problem on IL2CPP due to code stripping, but that was fixed a while ago. What version of the ARCore package do you have?

 

I'm using version 1.0.0-preview.24 of ARCore XR Plugin and 1.0.0-preview.22 of AR foundation, it says they're both up to date in the package manager, unity version 2018.3.7f1.

 

I've also tried updating Unity to 2019.1.0f2 and updating the packages to AR Foundation 1.10 (preview.6) and ARCore to 1.00-preview.24 but I'm still having the bug.

 

I have this issue as well. First launch fails after requesting camera permission.

 

@tdmowrer I sent you a private message with a full logcat of this.

 

Do you have a link.xml in your Assets folder? If not, ARFoundation should prompt you to create one. If you do, make sure you don't have any others elsewhere in your project as they may override this setting.

 

Seeing the same bug here- works fine in Mono, but when using IL2CPP first-time startup shows black screen.
There is only one link.xml file (auto-generated by AR Foundation) in my project.

Google Pixel 3 (behavior is the same on multiple devices)
Unity 2019.1.1f1
AR Foundation 1.1.0 p6
AR Core XR plugin 1.0.0 p24
ARKit XR plugin 1.0.0 p27

 

This appears to be a code stripping issue. The ARCorePermissionsManager implements a Java interface, so the callbacks it uses aren't explicitly referenced by any other C# code. When managed code stripped is enabled or IL2CPP backend is used, this causes those methods to get stripped by Unity.

We can prevent this in a future release of ARFoundation, but you can workaround it now by modifying your link.xml to

Code (csharp):

1. <assembly fullname="Unity.XR.ARCore" preserve="all" ignoreIfMissing="1"/>

(note preserve="all" instead of "none")

This may cause your apk to be a bit bigger but should fix the issue.

 

Thank you, that resolved the issue!

 

Has this been fixed in newer versions of AR Foundation?

 

It will be fixed in the next release (going through QA right now).

 

I have no link.xml do you have a full example of what it should contain? Including any other tags in the hierarchy.

 

Similar to https://github.com/Unity-Technologies/arfoundation-samples/blob/1.0/Assets/link.xml except change preserve="none" to preserve="all", e.g.,

Code (CSharp):

1. <linker>
2.     <assembly fullname="Unity.XR.ARCore" ignoreIfMissing="1" preserve="all"/>
3. </linker

 

Having the same problem. Trying setting "none" to "all" now.

 

Hi ,
Created this AR application using AR Foundation in unity for both : ios and android.
When built for ios everything was perfectly fine . also when built the same project for android with "Mono" back-end ( development build ) , everything was good , but when I built same thing using "IL2CPP" back-end , it gives following issues:'
1. Black Screen problem
2. Not detecting floor properly and object gets stuck to the camera ( I have attached a screenshots for this issue )

Please help me to resolve this issue.
thanks in Advance !

 

Hi
I have the same IL2CPP black screen problem / not requesting camera permission problem but with Vuforia...
Any workaround for that too?
Thanks

 

Having the same issue on Android too. In my case the issue is only the 2nd one, Not detecting the floor and object stuck to camera.

 

@sameel @Alond

I think it has to do with this issue (https://github.com/Unity-Technologies/arfoundation-samples/issues/96), turning of instant run inside android studio fixed it for me.

Inside Android Studio goto:
File → Settings → Build, Execution, Deployment → Instant Run and uncheck Enable Instant Run.

 

On Unity 2019.3b11 with this solution I get a compile error:

Spoiler: Error message

Failed running /Applications/Unity/Hub/Editor/2019.3.0b11/Unity.app/Contents/il2cpp/build/UnityLinker.exe -out="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/tempStrip" -x="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/../platform_native_link.xml" -x="/var/folders/nc/9blh334s75z5zxm02rn6dyg40000gn/T/tmpd1f4a6.tmp" -x="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/TypesInScenes.xml" -x="/Users/AlexBo/Development/UnityProjects/URP/Assets/link.xml" -d="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed" --include-unity-root-assembly="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/Assembly-CSharp.dll" --include-unity-root-assembly="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/Unity.RenderPipelines.Core.Runtime.dll" --include-unity-root-assembly="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/Unity.RenderPipelines.Universal.Runtime.dll" --include-unity-root-assembly="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/UnityEngine.UI.dll" --dotnetruntime=il2cpp --dotnetprofile=unityaot --use-editor-options --include-directory="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed" --rule-set=Conservative --editor-data-file="/Users/AlexBo/Development/UnityProjects/URP/Temp/StagingArea/assets/bin/Data/Managed/EditorToUnityLinkerData.json" --platform=Android --enable-engine-module-stripping --engine-stripping-flag=EnableUnityConnect --engine-stripping-flag=EnablePerformanceReporting --engine-stripping-flag=EnableAnalytics --engine-modules-asset-file="/Applications/Unity/Hub/Editor/2019.3.0b11/PlaybackEngines/AndroidPlayer/Whitelists/../modules.asset"

stdout:
Fatal error in Unity CIL Linker
System.Xml.XmlException: Unexpected end of file has occurred. The following elements are not closed: linker. Line 3, position 9.
at System.Xml.XmlTextReaderImpl.Throw (System.Exception e) [0x00027] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.Throw (System.String res, System.String arg) [0x00029] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.Throw (System.Int32 pos, System.String res, System.String arg) [0x0000c] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.ThrowUnclosedElements () [0x000cc] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.ParseEndElement () [0x001f7] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.ParseElementContent () [0x00149] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XmlTextReaderImpl.Read () [0x00085] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XPath.XPathDocument.LoadFromReader (System.Xml.XmlReader reader, System.Xml.XmlSpace space) [0x00228] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XPath.XPathDocument..ctor (System.String uri, System.Xml.XmlSpace space) [0x00013] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at System.Xml.XPath.XPathDocument..ctor (System.String uri) [0x00000] in <1d98d70bb7d8453b80c25aa561fdecd1>:0
at Unity.Linker.Steps.Resolution.UnityResolveFromXmlStep..ctor (System.String file) [0x00000] in <98b21eac6f13437abe8e0f36445fe9d3>:0
at Unity.Linker.UnityDriver.ParseArguments (Mono.Linker.Pipeline p, Unity.Linker.UnityLinkContext context, System.Collections.ArrayList custom_steps, Mono.Linker.I18nAssemblies& assemblies) [0x001d1] in <98b21eac6f13437abe8e0f36445fe9d3>:0
at Unity.Linker.UnityDriver.Run () [0x0001b] in <98b21eac6f13437abe8e0f36445fe9d3>:0
at Unity.Linker.UnityDriver.RunDriverWithoutErrorHandling () [0x00007] in <98b21eac6f13437abe8e0f36445fe9d3>:0
at Unity.Linker.UnityDriver.RunDriver () [0x00002] in <98b21eac6f13437abe8e0f36445fe9d3>:0
stderr:

UnityEngine.Debug:LogError(Object)
UnityEditorInternal.Runner:RunProgram(Program, String, String, String, CompilerOutputParserBase) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:126)
UnityEditorInternal.Runner:RunManagedProgram(String, String, String, CompilerOutputParserBase, Action`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:71)
UnityEditorInternal.AssemblyStripper:RunAssemblyLinker(IEnumerable`1, String&, String&, String, String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:166)
UnityEditorInternal.AssemblyStripper:StripAssembliesTo(String, String&, String&, IEnumerable`1, UnityLinkerRunInformation) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:159)
UnityEditorInternal.AssemblyStripper:RunAssemblyStripper(UnityLinkerRunInformation) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:301)
UnityEditorInternal.AssemblyStripper:StripAssemblies(String, BaseUnityLinkerPlatformProvider, IIl2CppPlatformProvider, RuntimeClassRegistry, ManagedStrippingLevel) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:178)
UnityEditorInternal.IL2CPPBuilder:Run() (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:327)
UnityEditorInternal.IL2CPPUtils:RunIl2Cpp(String, String, IIl2CppPlatformProvider, Action`1, RuntimeClassRegistry) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:65)
UnityEditor.EditorApplication:Internal_CallGlobalEventHandler() (at /Users/builduser/buildslave/unity/build/Editor/Mono/EditorApplication.cs:442)

 

Make sure you close the linker tag

 

I still have this issue, is it something new with the arfoundation?

 

I was struggling to figure out the issue yesterday. The "ARCore XR Plugin" from the Package Manager has to also be installed along with the "AR Foundation" package. I had assumed that dependency would be installed automatically like the "AR Subsystems" package is (it makes sense why it isn't though). Project was building successfully with no errors in logcat it would just produce a black screen. It seems very obvious reading over the thread again but for some reason was not obvious to me before. Just thought I would make a note of it here if anyone has the same misunderstanding.

 

I have this problem when the scripting backend is Mono as well as IL2CPP.

I am have this issue on UNity 2019.2.17f1.
I did not have a link.xml in the assets folder, manually created as suggested in link above:

<linker>

    <assembly fullname="Unity.XR.ARFoundation" preserve="all" ignoreIfMissing="1"/>

    <assembly fullname="Unity.XR.ARExtensions" preserve="all" ignoreIfMissing="1"/>

    <assembly fullname="Unity.XR.ARCore" ignoreIfMissing="1" preserve="all"/>

    <assembly fullname="Unity.XR.ARKit" ignoreIfMissing="1" preserve="all"/>

    <assembly fullname="Unity.XR.ARKit.FaceTracking" ignoreIfMissing="1" preserve="all"/>

</linker>

Still getting a blank black screen.
Any help is greatly appreciated!

 

Hi, I'm getting the same problem here as well.
Unity Version 2019.3.6
ARFoundation 3.0.1
ARCore XR Plugin 3.0.1
ARKit XR Plugin 3.0.1

 

Hey, I am also having the same problem. Using:
Android 7
Unity Version 2019.3.3f
ARFoundation 2.1.4
ARCore XR Plugin 2.1.2

Basically I set up a scene with with a session and session origin GameObject and it doesn't work, the screen remains black.

Edit:

I Updated my phone to Android 8.0 and it is working now. Appearantly something is up with ARFoundation and Android 7.0.

 

same black screen problem
Unity Version 2019.3.7
ARFoundation3.0.1
ARCoreXR3.0
With UniversalRenderpipline -ForwardRender-ARUniversalRenderPipelinesAsser
build for android 8.0 Black Screen

 

Same issue
black screen problem
Unity Version 2019.3.7
Android 7.1

 

Just tried this on a pixel 3a xl I got for development and same issue black screen. Seem pretty common, I’m not too familiar with android build right now so a bit lost.

On iOS side I would expect this to be a camera permission issues.

 

Hi, i have the same issue. I tried doing and finding what you were telling the people above me to do, but i just couldn't figure it out. Can you send us a video how to fix this issue or inform me of a video that fixes this issue?

 

I was having a similar problem: getting black screen instead of camera feed, no prompt to use camera, camera access not granted, manually enabling camera access didn't help, the AR gods cursing me for no reason... Turns out my problem was different than the ones mentioned in this thread, so in case this will help anyone else, here's what I figured out:

My scene has two cameras: a regular camera, for menus and all non-AR stuff parts of the app, and an AR camera, used only for the AR parts of the app. There's a script that switches between them as necessary. If I start the app with the AR camera enabled and the regular camera disabled, that script turns the AR camera off and uses the regular camera on Awake. This works fine in the editor, but gives me the Black Screen of Mystery on the phone. But if I turn the AR camera off and the regular camera on in the editor before building, it solves the problem on the phone.

So I assume there's something going on where Android sees the app trying to access the camera, but then the app stops trying to use the camera when it switches to the non-AR camera at startup, so Android never prompts the user to allow access and some setting gets screwed and never fixed. I don't know, but this is what fixed it for me.

 

i got the same problem in iOS, my ar foundation camera comes black when change between scenes... i pay plus plan give me a solution please!.

 

Hi all. wanted to try ARFoundation 4.1 for Depth api of arcore. but having black screen. any idea?

Debug Message - "No active UnityEngine.XR.ARSubsystems.XRSessionSubsystem is available. Please ensure that a valid loader configuration exists in the XR project settings."

 

Be sure to configure the provider plugin for your target system.

https://docs.unity3d.com/Packages/c...n@4.1/manual/index.html#provider-plugin-setup

https://docs.unity3d.com/Packages/c.../migration-guide-3.html#xr-plug-in-management

 

Hi, I had the same problem. Changed from Mono to IL2CPP and AR didn't want to start (only black screen and my UI). Since my app starts in a non-AR scene, and my AR scenes are downloaded later as Assetbundles, the IL2CPP code stripping probably never thought that I would ever need AR Foundation...

I fixed it by adding a link.xml file to my Assets folder:

Code (CSharp):

1.  
2. <linker>
3.     <assembly fullname="Unity.XR.ARCore" ignoreIfMissing="1" preserve="all"/>
4.   <assembly fullname="Unity.XR.ARKit" ignoreIfMissing="1" preserve="all"/>
5.   <assembly fullname="Unity.XR.ARFoundation" ignoreIfMissing="1" preserve="all"/>
6.   <assembly fullname="Unity.XR.ARSubsystems" ignoreIfMissing="1" preserve="all"/>
7. </linker>
8.  

It wasn't enough to add ARCore and ARKit to the file. I also needed ARFoundation and ARSubsystems in it.

Hope it helps!

Unity version 2019.4.0f1
ARFoundation 4.0.2
ARCore 4.0.4
ARKit 4.0.2
Device Google Pixel 2

 

This did not work for me. Please suggest a fix been spending hours on this issue! It works in unity but not on mobile. Just a black screen on mobile with my canvas objects.

 

Same here, i now cant work on my project at all.

How would this be missed on testing is beyond me, please offer a fix asap. I also donwloaded all latest demo scenes from github etc, none works at all, camera just not open now.

 

Hi,

The system was working fine and all setup was correct before upgrading to AR foundation 4.1, so is there any new undocumented setup required ?

Thank you in advance.

 

Black screen on 4.1.0 on Android, yay

 

Have you enabled ARCore in Project Settings > XR Plug-in Management?

 

I can confirm I did that, I am very familiar with XR Plugin management, I have found that sometimes rebuilding over the same app on Android causes a black screen that doesn't go away if you restart the phone or the app. It is very prohibitive to development. I am using ARFoundation and plugins versions 4.0.8 and Unity 2020.1.6f1

I will report bugs later in the week I just currently have a deadline to meet with a Simple AR demo and the ARFoundation Samples/Demos have fallen over for me in so many ways so far the past few days. Black screens while testing is giving me little faith in live demoing.

 

Yep same thing here !

There is an other way to get the black screen :

1. Remove app on android device
2. Build and run from unity
3. Close the app
4. Run the app from mobile device
5. Black screen !

Unity 2020.1.6f1 & AR Foundation 3.1.5.

 

THIS ^ This was exactly what I was doing when it happened. Feels like nobody tests these tools out in actual development environments. Happens on ARFoundation 4.0.8 and above too still.

 

That sounds like a bug. However, we do test this scenario regularly, and I have not been able to reproduce it using the instructions @Alexis_AG provided. I've tried several permutations including Mono / IL2CPP and different types of permissions (deny/only this time/while using the app), and closing the app without selecting a permission option.

Could you please log a bug with a repro project and post the issue number here?

 

I will do thanks for looking into this. It caused me a lot of concern when I had a live demo the next day and doing more test builds.

 

Hi. After the first loading scene with ARSession from menuScene - black screen. Reload scene from menuScene - Ok.
-Unity 2019.4.0f1,
-ARFoundation 4.1.0 preview5
-ARCore XR Plugin 4.1.0 preview5
-ARKit XR Plugin 4.1.0 preview5

 

Hello,
I had this problem when I needed to export an android project from unity. Found that the build is running in debug mode. The problem was proguard.
Here's the solution:
https://stackoverflow.com/questions/57447730/arcore-unity-proguard-problems

 

@tdmowrer worth looking at this, I didn't think to check this

 

If you can see black screen,
you shoud change AR Foundation SDK version or Unity Project version.
I found didn't work AR Foundation Sdk version

Unity Project 2019.4.0f1
ARFoundation version 3.0.1 / 4.0.2 / 4.0.8 은 Not working
ARFoundation version 3.1.3 Working

Unity Project 2019.3.15f1
ARFoundation version 4.0.2 Working

And if you use URP
you should setting Pipeline Asset to 'Add Render Feature'


I hope my information will solve your problem. XD

 

Is there any update on a fix from the suggestions above?