[Plugin] Leap Motion - Event Driven

[Solidus569]

Can you make a blank blueprint project that can replicate this issue on demand?

Also what hmd are you using?

Yes, I should clarify though, this was for UE 4.10. Whatever magic was done for the 4.11 plugin has fixed the issue (it looks like mostly wrapping everything in UPROPERTY and modifying the private classes some). However in 4.10 all you have to do to replicate is:

>make a blank character
>add the leap interface
>add the "handsmoved" event node to the event graph
>from the LeapHand that is returned by the "handsmoved" node call "fingers"
>play and hold hand in front of face for ~1 minute

this should be enough to cause the crash as it happens specifically in the "setfingerlist" function when you say _private->fingers = fingers which is triggered on calling "fingers" from blueprint. If you'd like me to actually build a blueprint and post it here I can, but the steps are fairly simple.

Also, using Rift DK2 (I've tried plugging the leap into the headset and into the computer, doesn't make a difference)

Thanks again!

NOTE: We've moved to 4.11 anyway so it doesn't really matter anymore I suppose (last post was before that decision was made). However this may still be useful information for people stuck on the older versions.

[7hny]

echo_lo_L_PhysicsAsset incorrect collision setup

Hi getnamo, echo_lo_L_PhysicsAsset has incorrect collision setup, there are unnecessary capsules obstructing of line trace from HMD, deleting them fixes the issue. Goodday

[getnamo]

Yes, I should clarify though, this was for UE 4.10. Whatever magic was done for the 4.11 plugin has fixed the issue (it looks like mostly wrapping everything in UPROPERTY and modifying the private classes some). However in 4.10 all you have to do to replicate is:

>make a blank character
>add the leap interface
>add the "handsmoved" event node to the event graph
>from the LeapHand that is returned by the "handsmoved" node call "fingers"
>play and hold hand in front of face for ~1 minute

this should be enough to cause the crash as it happens specifically in the "setfingerlist" function when you say _private->fingers = fingers which is triggered on calling "fingers" from blueprint. If you'd like me to actually build a blueprint and post it here I can, but the steps are fairly simple.

Also, using Rift DK2 (I've tried plugging the leap into the headset and into the computer, doesn't make a difference)

Thanks again!

NOTE: We've moved to 4.11 anyway so it doesn't really matter anymore I suppose (last post was before that decision was made). However this may still be useful information for people stuck on the older versions.

Sounds like it was a garbage collection issue. Good to hear it's been resolved in 4.11.

Hi getnamo, echo_lo_L_PhysicsAsset has incorrect collision setup, there are unnecessary capsules obstructing of line trace from HMD, deleting them fixes the issue. Goodday

Nice fix, could you make a pull request with the modified asset on the github page?

[vhung92]

Once you have a collision point on the surface, you need to convert the 3d location into 2d scaled from 0-xMax, 0-yMax where the max values are given by the widget borders set in our widget component.

I got it working, thanks! Do you have any tips for upgrading my 4.10 project to 4.11 by the way? Do I upgrade and re-parent my subclasses (I've subclassed LeapEchoCollisionCharacter from the plugins folder) or how would I do it as painless as possible without breaking any references?

[getnamo]

I got it working, thanks! Do you have any tips for upgrading my 4.10 project to 4.11 by the way? Do I upgrade and re-parent my subclasses (I've subclassed LeapEchoCollisionCharacter from the plugins folder) or how would I do it as painless as possible without breaking any references?

Upgrade and set your ActiveClass redirects?

MyGameDir\Config\DefaultEngine.ini see https://answers.unrealengine.com/que...lass-none.html

not sure it's always been a bit painful for me :P If you find a good way, let me know!

[vhung92]

Upgrade and set your ActiveClass redirects?

MyGameDir\Config\DefaultEngine.ini see https://answers.unrealengine.com/que...lass-none.html

not sure it's always been a bit painful for me :P If you find a good way, let me know!

Guess there's no way for an upgrade to be painless :P I'll experiment and see what I can come up with!

[TheBricktop]

Hey Getnamo
Im trying to follow Your tutorial on jenga blocks, but im still stumped, Leap echo Hands doesn't seem to generate OnCollisionEvent (although they collide properly with other physic meshes), this is the first time something like this is happening for me in Unreal Engine.

[spacecrafter3d]

Hey,

I feel like I must be missing something here. I am trying to use this plugin completely from C++. I added an instance of ULeapController as a component on my custom actor. I inherited from ILeapEventInterface. But when I tried to override the callback methods, I found that they are not virtual. Am I misunderstanding something here, or is C++ integration currently impossible?

Thanks

[lennylightspeed]

Hey Getnamo, I'm trying to check out the AR/VR transition example in your guide. After activating the plugin in 4.11.1 I can change the default pawn class to the passthrough example, but when I go to change player controller there is not a VRplayerController listed. In the preview mode the passthrough works, but is unable to switch with the gesture. I'm pretty new to all this and feel like I'm missing something simple. Any help you can give would be great. Thanks!

[TheBricktop]

Okay here' a quickie: id like to make an object with raw feed from leap motion camera as its material, how can I do it? Currently im trying to feed dynamic material with left camera image but during runtime its not working.

[7hny]

Hi getnamo. There is a problem with overlap events. When I attach a mesh to hand socket (echo hands), overlap event triggers on and off constantly (every frame?). Everything is ok when this mesh is not attached to the socket (overlap events are fired only once). Any ideas on how to fix it? Thanks.

[Techies]

Everytime I try and enable to leap motion plugin with 4.11.0 in a new project I get a crash when I restart.

[no1zard]

now is apply only hand direction in world.
I want to get direction of swipe gesture by hmd direction.
How do i get that? sorry about that poor english^^

[no1zard]

now is apply only hand direction in world.
I want to get direction of swipe gesture by hmd direction.
How do i get that? sorry about that poor english^^

[TheBricktop]

After using floating image hands i've got this error and crash:

MachineId:7B048135469A17A7FB5AA5A63B273E9A
EpicAccountId:5443fea92c13481992b91d0ba827289e

Access violation - code c0000005 (first/second chance not available)

UE4Editor_LeapMotion!FPrivateLeapImage::Texture32FromLeapImage()
UE4Editor_LeapMotion!ULeapController::InterfaceEventTick()
UE4Editor_Engine!FActorComponentTickFunction::ExecuteTickHelper<<lambda_13c1d0f62b5fcaced3ce7b89bd3d0f91> >() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\classes\gameframework\actor.h:2722]
UE4Editor_Engine!FActorComponentTickFunction::ExecuteTick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\components\actorcomponent.cpp:710]
UE4Editor_Engine!FTickFunctionTask:oTask() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\ticktaskmanager.cpp:228]
UE4Editor_Engine!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\public\async\taskgraphinterfaces.h:886]
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\async\taskgraph.cpp:779]
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilIdle() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\core\private\async\taskgraph.cpp:541]
UE4Editor_Engine!FTickTaskSequencer::ReleaseTickGroup() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\ticktaskmanager.cpp:503]
UE4Editor_Engine!FTickTaskManager::RunTickGroup() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\ticktaskmanager.cpp:1373]
UE4Editor_Engine!UWorld::RunTickGroup() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\leveltick.cpp:702]
UE4Editor_Engine!UWorld::Tick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\engine\private\leveltick.cpp:1198]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\unrealed\private\editorengine.cpp:1356]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\editor\unrealed\private\unrealedengine.cpp:370]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\launchengineloop.cpp:2644]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++ue4+release-4.11\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll

its fresh install of ue 4.11 with official leapmotion plugin test level .