How to set a timer for the next tick in Unreal Engine

In Unreal Engine, it is possible to set a delay for the function to execute after a single tick, which is sometimes useful when working with UMG/Slate side of things where the widget properties are only available after a complete rebuild, such as obtaining the desired size of the widget’s geometry, which is often not accessible right after initializing or constructing the widget. In such cases, you may want to implement a delay, as described in this article , but sometimes even a single tick delay is sufficient and can enhance the overall user experience, preventing visual hitches and abrupt interactions....

September 15, 2023 · 2 min · Georgy Treshchev

Efficient HTTP file download by chunks in Unreal Engine C++

Chunk downloading is a technique used to retrieve large binary data from the server in separate parts, ensuring reliability and compatibility across different platforms. Unreal Engine’s HTTP module has a limitation of 2GB for binary HTTP response content due to internal restrictions (specifically, TArray<uint8> uses the int32 size type, which has a maximum value of 2,147,483,647, approximately 2 GB in our case). To overcome this limitation, we can use the Range HTTP header supported by most servers, without requiring any file preparation or segmentation....

May 21, 2023 · 4 min · Georgy Treshchev

How to save UObject that is represented as an asset in Unreal Engine

You can save any UObject that is represented as an asset within a UPackage using this method: bool SaveToAsset(UObject* ObjectToSave) { UPackage* Package = ObjectToSave->GetPackage(); const FString PackageName = Package->GetName(); const FString PackageFileName = FPackageName::LongPackageNameToFilename(PackageName, FPackageName::GetAssetPackageExtension()); FSavePackageArgs SaveArgs; // This is specified just for example { SaveArgs.TopLevelFlags = RF_Public | RF_Standalone; SaveArgs.SaveFlags = SAVE_NoError; } const bool bSucceeded = UPackage::SavePackage(Package, nullptr, *PackageFileName, SaveArgs); if (!bSucceeded) { UE_LOG(LogTemp, Error, TEXT("Package '%s' wasn't saved!...

February 5, 2023 · 1 min · Georgy Treshchev

How to use variant in Unreal Engine

There is a std::variant class template in the standard library that is essentially a type-safe  union. It is generally used when we are not sure in advance which object should be populated from our list of object types, so we assume that one of the specified objects must be there at a time. Unreal Engine has an alternative implementation called TVariant that works the same, except that all the types in the declaring template parameter pack must be unique....

December 30, 2022 · 1 min · Georgy Treshchev

How to use mutex in Unreal Engine

Unreal Engine has an alternative implementation of std::mutex called FCriticalSection which makes it possible for your data to be safely accessed from different threads, preventing race conditions. This takes the same approach, handling it with one thread locking until the other thread completes the necessary operations. There are two ways to handle lock/unlock logic. The first is low-level, which is used to directly lock and unlock threads. Use with caution due to possible deadlocks ....

December 21, 2022 · 2 min · Georgy Treshchev