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Unity - Crash when detecting cloud object too quickly

January 9, 2019 - 10:07pm #1

Vuforia SDK Version: 7.5.26 -

Description with steps to reproduce: The formatting doesn't seem great in the preview so I have pastebin'd this description just in case: -----------------> https://pastebin.com/fTZm7wEm

Using Unity 2018.3.0f2, but experienced at least on 2018.2.11f1 as well.

The Target Finder seems to cause a crash if it finds cloud reco image target within a few frames of the cloud reco behaviour being enabled.
It can be quite hard to replicate, but is more consistent on slower internet.

1. Setup a scene with a Vuforia Cloud Reco Behaviour and a linked Image Target Behaviour. Ensure this scene is accessible
2. Create a script that disables both of these once the Cloud Reco is initialised
3. Create a script that will enable these again on a user interaction event, such as a tap. Ensure this is not possible until the Cloud Reco Behaviour initialise callback is triggered.
(optional: set the focus mode to continuous auto)
4. Set up the Vuforia configuration asset file to be linked to a License. Also ensure the Cloud Reco Behaviour is using the desired access key(s) from your cloud database
5. Create a target in your Cloud database with any image that will achieve 5 stars. It may or may not be important to set the name as a GUID and set the width to 1. Leave the metadata empty.
6. Build for Android or iOS
7. Launch the app. Wait for the cloud reco to initialise
8. Aim the camera at your marker target, ensuring it is in focus and ready to scan.
9. Trigger the user interaction that will enable the Cloud Reco Behaviour and Image Target Behaviour (e.g. user tap)
10. App will likely crash or freeze

It may not be particularly useful, but I've pastebin'd the iOS crash log here: https://pastebin.com/5z2v37cx
I've also used OSX terminal to print out some of the function name and locations from Thread 0 (from the aforementioned log): https://pastebin.com/6mv9Xx4D -

Development OS (Mac OS X, Windows, Linux): Windows, built on a Mac machine (Unity Cloud Build) -

Mobile OS and Version: iOS 12, Android 8.0.0 -

Mobile Device Manufacturer and Model name: Apple iPad7, Samsung S9+ -

Do the Vuforia Sample Applications show the same behavior?: Unknown. I believe this to be an edge case that may not have been anticipated.

Unity - Crash when detecting cloud object too quickly

January 10, 2019 - 2:36pm #3

Below is the call stack from the thread that crashed. Looks like it's possibly coming from a Unity engine file, so I'll report it to them too.

Thread 0:

0 -> UnityUpdateJoystickData (in dsg) (iPhone_Sensors.mm:708)

1 -> il2cpp::vm::String::New(char const*) (in dsg) (String.cpp:64)

2-> TargetFinder_Update_m18496C49D5DC0C1BBFC44BFF17E4653FF08397CC (in dsg) (Bulk_Vuforia.UnityExtensions_2.cpp:27365)

3-> ObjectRecoBehaviour_Update_mC1278D7B4A28EA11C4D1A1F827656C92D2BAE64D (in dsg) (Bulk_Vuforia.UnityExtensions_1.cpp:34415)

Unity - Crash when detecting cloud object too quickly

January 10, 2019 - 1:25pm #2


I'm *not* seeing where Vuforia is the source of the crash in the log you provided: https://pastebin.com/5z2v37cx

Am I missing something?


Vuforia Engine Support

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