Description

When attempting to get the vertex color of an instance of of a static mesh that is painted after placing it in the World Viewport. The Editor crashes returning an "Unhandled Exception".

The cause of this crash seems to be from a custom C++ Blueprint Function Library Class GetSectionFromStaticMesh(). It worked fine for Vertices and Normals, but when trying to access VertexColor of the ColorVertexBuffer it results in an Editor Unhandled exception.

 

 

 

Steps to Reproduce

From Project Sample:

1. Unzip VertexColor.Zip
2. Generate Project File Solutions by right clicking on VertexColor.UProject.
3. Launch Project either from .UProject or by Visual Studio.
4. Press PIE

Result: Unhandled Exception Crash. See Call Stack for full log

Expected: The ability to get VertexColor from a modified instance of a Static Mesh

Note: This crash comes from user's custom C++ UFunction Library that I have also included as a separate notepad file.

Callstack
Unhandled exception

UE4Editor_VertexColor!UVerticesInformations::GetNewIndexForOldVertIndex() [c:\users\nicholas.montefusco\desktop\vertexcolor\source\vertexcolor\verticesinformations.cpp:23]
UE4Editor_VertexColor!UVerticesInformations::GetVerticesInformations() [c:\users\nicholas.montefusco\desktop\vertexcolor\source\vertexcolor\verticesinformations.cpp:61]
UE4Editor_VertexColor!UVerticesInformations::execGetVerticesInformations() [c:\users\nicholas.montefusco\desktop\vertexcolor\source\vertexcolor\verticesinformations.h:37]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4643]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:904]
UE4Editor_CoreUObject!UObject::ProcessContextOpcode() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2314]
UE4Editor_CoreUObject!ProcessLocalScriptFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:974]
UE4Editor_CoreUObject!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:809]
UE4Editor_CoreUObject!ProcessLocalFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1033]
UE4Editor_CoreUObject!ProcessLocalScriptFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:974]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1058]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4643]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1464]
UE4Editor_Engine!AActor::ProcessEvent() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:769]
UE4Editor_Engine!AActor::BeginPlay() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:3383]
UE4Editor_Engine!AActor::DispatchBeginPlay() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:3343]
UE4Editor_Engine!AWorldSettings::NotifyBeginPlay() [d:\build\++ue4\sync\engine\source\runtime\engine\private\worldsettings.cpp:253]
UE4Editor_Engine!AGameStateBase::HandleBeginPlay() [d:\build\++ue4\sync\engine\source\runtime\engine\private\gamestatebase.cpp:177]
UE4Editor_Engine!UWorld::BeginPlay() [d:\build\++ue4\sync\engine\source\runtime\engine\private\world.cpp:3948]
UE4Editor_Engine!UGameInstance::StartPlayInEditorGameInstance() [d:\build\++ue4\sync\engine\source\runtime\engine\private\gameinstance.cpp:413]
UE4Editor_UnrealEd!UEditorEngine::CreatePIEGameInstance() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\playlevel.cpp:3341]
UE4Editor_UnrealEd!UEditorEngine::PlayInEditor() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\playlevel.cpp:2466]
UE4Editor_UnrealEd!UEditorEngine::StartQueuedPlayMapRequest() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\playlevel.cpp:1280]UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\editorengine.cpp:1532]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:403]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3967]
UE4Editor!GuardedMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launch.cpp:168]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:145]
UE4Editor!WinMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:275]
UE4Editor!__scrt_common_main_seh() [d:\agent\_work\3\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll

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Unresolved
ComponentRendering
Affects Versions4.224.234.244.25
Target Fix4.25
CreatedNov 6, 2019
UpdatedNov 6, 2019