Unreal 4.26. Preview 01 compile error

[zibertd]

Situation: Up until 4.25 I was able to compile the master branch of the Unreal plugin without any problems. I could even use the plugin if I start the Diagnostic Visualizer, and run it parallel with the Unreal Engine.

Problem: 4.26 compile gives this error:

LeapImage.cpp(83): error C2027: use of undefined type 'FTexture2DResource'
LeapImage.cpp(87): error C2027: use of undefined type 'FTexture2DResource

error MSB3073: The command "C:\Windows\System32\chcp.com 65001 >NUL
error MSB3073: "C:\Unreal Engine\UE_4.26\Engine\Build\BatchFiles\Build.bat" LMPluginEditor Win64 Development -Project="D:\LeapMotion\LMPlugin\LMPlugin.uproject" -WaitMutex -FromMsBuild" exited with code 6

Like I said, 4.25 build perfectly fine, no errors whatsoever. In 4.26 something changed. Could be even something different than this. Can you guys help me out to find what exactly?

Thanks in advance.

[BryanChrisBrown]

It's likely a problem with the FTexture2DResource function being changed. Since 4.26 is still in preview it's possible that there may be more breaking changes that occur until release. Generally I'd recommend to not use preview versions of unreal engine in production, which is the same advice epic give.

Visual Studio is generally pretty good at telling you what's broken. If you absolutely need it fixed take a look at the LeapImage.cpp file and see if the error has a "quick fix" option. If not it'll probably take Ultraleap a bit of dev time to solve it.

[zibertd]

Hey Bryan,

Thanks for the answer. Yeah, I reverted back to 4.25. It's a problem with forward declaration of functions, since 4.26 changed the way where it declared it's functions/classes. I haven't found any quick fix options, but that's all right, anyway, since I'm going to wait for 4.26 official release, and take if from there.

Unreal's plugin does need an update, though. The last substantial one was over a year ago. 4.26 being a semi-huge leap for Unreal would be a perfect opportunity.

[dankirby]

We are currently working on updating our Unreal plugin to officially support UE4.25 and you can see the latest updates to add support for Unreal 4.25 here. Please note that this is still being tested.

[zibertd]

I just recieved a notification the the new version of the plugin for Unreal has been released:

It's on this page:

Releases · leapmotion/LeapUnreal

The first that is written is:

"Update to get plug working with Unreal 4.26."

What does this mean exactly? When I try to compile it from the source, the same forward delegate compile error occurs. Official UE 4.26 released today, btw.

[dankirby]

Unfortunately this was a typo, this update for our Unreal plugin was to get this working with UE4.25.

Apologies for the confusion.

With regards to 4.26, watch this space!

[Denrunner]

I think they must have changed something already, because I was able to compile the latest Github master for 4.26.1 without any problems!

[zibertd]

Yeah, as of 25. January, judging by the changelog, they made it compatible with 4.26! But not just the plugin, but also the Unreal modules, so I can get to test it without having 5+ different versions of Unreal!

I also noticed how tracking is far more stable, but still have to use the diagnostic visualizer to change it to head mounted orientation. All in all, well done gents!

[grifu]

I've followed all steps with Visual Studio Community 2019, but still, LeapMotion returns an error while compiling in Unreal 4.26.1,

After starting the project it prompts for rebuilding the plugin, then it starts building
It returns the following error:
LeapImage (83): error C2027: use of undefined type 'FTexture2DResource'

Denrunner, what version of Github did you use?

[grifu]

Ok, I was able to compile leapmotion plugin in UE4.26 using the github version.

[zibertd]

@grifu

That's great! Sorry for not getting back sooner, but for the future reference, I always use GitHub desktop, and pull master branches from LeapUnreal, and LeapUnrealModules.

[Denrunner]

grifu I used the github master and it compiled out of the box on 4.26.1.. FTexture2DResource sounds like you might have grabbed the previous 4.25 version

[grifu]

Thanks!
That's right, I was using the 4.25, which presents the FTexture issue.
Now it's working fine, even with the LeapModules.
I'm working with Leapmotion for digital puppetry through desktop (not VR). The modules provide a Mannequin already rigged for VR, is there a easy way to adjust the Leap Mannequin Autohands blueprint for desktop? Should I create a new topic?

[dankirby]

Use setLeapMode on beginPlay to desktop, the rest of the process will remain the same. I have included a screenshot below to help: