Crashes in FVideoCallbackHandler::SampleCB when stopping the game

[fungiboletus]

Hei,

I'm using your plugin with Unreal 4.15 and it works very well most of the time. Sometimes it crashes after I stop the game from the editor, and the call stack says it comes from the ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER block in FVideoCallbackHandler::SampleCB.

My guess is that this block is sometimes executed after the games stops, and the code is accessing deallocated memory. Could you suggest a small fix ?

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

UE4Editor_Webcamera!FTexture2DResource::GetTexture2DRHI() [c:\program files\epic games\ue_4.15\engine\source\runtime\engine\public\textureresource.h:276]
UE4Editor_Webcamera!`FVideoCallbackHandler::SampleCB'::`8'::EURCMacro_UpdateTextureRegionsData::DoTask() [v:\project\plugins\webcamera\source\private\videocallbackhandler.cpp:74]
UE4Editor_Webcamera!TGraphTask<`FVideoCallbackHandler::SampleCB'::`8'::EURCMacro_UpdateTextureRegionsData>::ExecuteTask() [c:\program files\epic games\ue_4.15\engine\source\runtime\core\public\async\taskgraphinterfaces.h:883]
UE4Editor_Core
UE4Editor_Core
UE4Editor_Engine
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll