Fix freezing the UE editor when quitting game mode after capturing (Linux).

[stefanbuettner]

Hey there,

I was using the project on Ubuntu 18.04 with the UnrealEngine 4.21.3 built from source.
I could use the project according to the documentation without problems. But when quitting the game mode after recording data, the editor would freeze.

It was locking in the FNVImageExporter_Thread::Stop on the Thread->Kill(true); statement and therefore probably on HavePendingImageEvent->Wait();
Not resetting the HavePendingImageEvent when stopping the thread fixed the problem.

I don't know if this was also a problem on Windows or Mac neither if this change introduces a problem on these platforms. Yet, "it worked on my machine".

Cheers,
Stefan

[Dutzel]

Have you had the "NDDS could not be compiled." Error? What did you do to fix it?

[stefanbuettner]

I had this error at some point but don't know how and why it went away. I also had the problem that the UBT recompiled the whole engine when compiling the plugin.
So I cloned the Dataset_Synthesizer project again, skipped the project conversion and everything went fine.

[mikeramseybg]

Hi there: Curious if either of you have used ndds in a built package? I’m using it to generate some data sets and I’ve run into a bit of an issue getting the plugin working entirely correctly when “packaged” in unreal – which allows a project to be run outside of the unreal editor environment. The instance segments are getting a invalid/nonexistent vertex colors to be used in the mask. Here’s a sample instance image: [cid:image002.png@01D4EE29.567B0680] Where this is what I’m seeing (as expected) from within the unreal editor builds: [cid:image005.png@01D4EE29.567B0680] Curious if you had any thoughts on this? Thanks, mike

[Dutzel]

Thanks for your quick answer! Hmm... what is your Unreal Version? I cloned the version 4.21 but now it shows the version is 4.22... all i did was following these instructions:
https://docs.unrealengine.com/en-us/Platforms/Linux/BeginnerLinuxDeveloper/SettingUpAnUnrealWorkflow

Did you do that as well?

[stefanbuettner]

@Dutzel I didn't follow this very description for building the engine but the one in Engine/Build/BatchFiles/Linux/README.md in the engine source. But the stepsare the same - ./Setup.sh, ./GenerateProject.sh and make. I used the 4.21.2-release tagged version.

@mikeramseybg I didn't use it in a package build. No experience there.

[mrkcass]

Had no problems until the last official commit. After that I was locking up every time I stopped the player. This commit fixed that problem.

Have several on the team using NDDS and will pass the word along.

Thank you!!!

[Sserpenthraxus-nv]

Thanks very much for this change.