This is an infrequent crash in the 4.18 release. Users have not provided any descriptions of their actions when the crash occurred.
Source Context
849 uint32 UMaterialExpression::GetOutputType(int32 OutputIndex)
850 {
851 // different outputs should be defined by sub classed expressions
852 if (IsResultMaterialAttributes(OutputIndex))
853 {
854 return MCT_MaterialAttributes;
855 }
856 else
857 {
858 ***** FExpressionOutput& Output = GetOutputs()[OutputIndex];
859 if (Output.Mask)
860 {
861 int32 MaskChannelCount = (Output.MaskR ? 1 : 0)
862 + (Output.MaskG ? 1 : 0)
863 + (Output.MaskB ? 1 : 0)
864 + (Output.MaskA ? 1 : 0);
865 swch (MaskChannelCount)
866 {
867 case 1:
868 return MCT_Float;
869 case 2:
870 return MCT_Float2;
871 case 3:
872 return MCT_Float3;
873 case 4:
Note: The function call node has a single output pin by default which is incorrect which is why linking it causes the crash.
Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\Build\++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers/Array.h] [Line: 610] Array index out of bounds: 0 from an array of size 0 UE4Editor_Engine!UMaterialExpression::GetOutputType() [materialexpressions.cpp:859] UE4Editor_UnrealEd!UMaterialGraphSchema::ArePinsCompatible() [materialgraphschema.cpp:306] UE4Editor_UnrealEd!UMaterialGraphSchema::CanCreateConnection() [materialgraphschema.cpp:522] UE4Editor_GraphEditor!FDragConnection::HoverTargetChanged() [dragconnection.cpp:55] UE4Editor_GraphEditor!FGraphEditorDragDropAction::SetHoveredPin() [grapheditordragdropaction.cpp:55] UE4Editor_GraphEditor!SGraphPin::OnDragEnter() [sgraphpin.cpp:649] UE4Editor_Slate!<lambda_f61e425f9587e96b799927cd214b1498>::operator() [slateapplication.cpp:5540] UE4Editor_Slate!FEventRouter::Route<FNoReply,FEventRouter::FBubblePolicy,FDragDropEvent,<lambda_f61e425f9587e96b799927cd214b1498> >() [slateapplication.cpp:234] UE4Editor_Slate!FSlateApplication::RoutePointerMoveEvent() [slateapplication.cpp:5534] UE4Editor_Slate!FSlateApplication::ProcessMouseMoveEvent() [slateapplication.cpp:5965] UE4Editor_Slate!FSlateApplication::OnMouseMove() [slateapplication.cpp:5899] UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [windowsapplication.cpp:1763] UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [windowsapplication.cpp:2171] UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [windowsapplication.cpp:888] UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [windowsapplication.cpp:725] user32!UserCallWinProcCheckWow() user32!DispatchMessageWorker() UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [windowsplatformapplicationmisc.cpp:129] UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3220] UE4Editor!GuardedMain() [launch.cpp:166] UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134] UE4Editor!WinMain() [launchwindows.cpp:210] UE4Editor!__scrt_common_main_seh() [exe_common.inl:253] kernel32!BaseThreadInitThunk() ntdll!RtlUserThreadStart()
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-52616 in the post.
| 0 |
| Component | UE - Rendering Architecture - Materials |
|---|---|
| Affects Versions | 4.18 |
| Target Fix | 4.19 |
| Fix Commit | 3794273 |
|---|---|
| Main Commit | 3807911 |
| Created | Nov 21, 2017 |
|---|---|
| Resolved | Dec 5, 2017 |
| Updated | Nov 2, 2021 |