Flow v1.4

This is the upcoming release. This page is updated regularly, after pushing changes to the repository.

This release includes pull requests from the community: ArseniyZvezda (Arseniy Zvezda), bohdon (Bohdon Sayre), LindyHopperGT (Greg Taylor), lfowles (Landon Fowles), Mephiztopheles (Markus Ahrweiler), michalmocarskiintermarum (Michał Mocarski), ryanjon2040 (Satheesh), Vi-So (Alex van Mansom).

This is the first release for UE 5.2, and the last one for UE 5.0.

Upgrade notes

Do not update directly from version 1.0 to this version. Important fixups of deprecated properties have been removed in this version.

New: Message Log support

• Added Validate toolbar action calling data validation on the entire asset, checking all Flow Nodes. If any issues are found, these are reported in the new Validation Log window.
• Node validation uses the new UFlowNode::ValidateNode method which is available in C++ only.
• Added Runtime Log windows displaying runtime message set by Flow Nodes, using methods LogError, LogWarning, and LogNote.
• Editor throws a notification on the PIE end if there are any warnings or errors reported.
• Refactored plain debugger struct into Flow Debugged Subsystem which gathers Runtime Logs.
• Fixed: UFlowNode::LogError doesn't execute its logic in Shipping builds anymore. Also, prevented calling runtime log methods on templates of the Flow Asset.

Graph

• Refresh command now also recreates UFlowGraphNode instances if a given UFlowNode now has a different UFlowGraphNode assigned. Only applicable to C++ classes, as blueprint nodes cannot have custom UFlowGraphNode. (reworked pull request by ArseniyZvezda)
• Improved filtering of given Flow Node subclasses in Flow Graph Schema.
• Added GetStartNode method to Flow Asset, available in C++ only.
• The FlowGraphSchema will now create default nodes for any CustomInputs that exist when the asset is first created. (contributed by LindyHopperGT)
• Corrected templated version of UFlowAsset::GetOwner(). (contributed by ryanjon2040)

Flow Node

• Added Node Color property directly to the Flow Node class. (contributed by ryanjon2040)
• Added log message while node executes in Disabled or PassThrough mode.
• Added options to disable printing Signal Mode messages to the Output Log. (contributed by ryanjon2040)
• Added editor user setting bShowNodeDescriptionWhilePlaying allowing to hide of static node descriptions while PIE/SIE is active. (contributed by ryanjon2040)
• Moved the TryGetRootFlowActorOwner method from the PlayLevelSequence node to the base class. Also provided a component version of this same code. (contributed by LindyHopperGT)
• Exposed direct access to Flow Node connections in C++.
• Fixed: correctly updating user-add pins on nodes like Sequence after removing one of pins.
• Fixed: rare crash if node would trigger output on exiting game.
• Compilation-breaking change: Removed template method LoadAsset as it was simply redundant.
• Optimized building debug-only status strings, when using methods like GetProgressAsString.

Specific Flow Nodes

• Introduced a superclass to UFlowNode_CustomInput and UFlowNode_CustomOutput so they can share more code. (contributed by LindyHopperGT)
• Exposed CustomInput Add/Remove functions on UFlowNode to allow subclasses to modify the CustomInputs array. (contributed by LindyHopperGT)
• Added a UseAdaptiveNodeTitles option to optionally make CustomInputs integrate their EventName into the title for the node. This defaults to false (to preserve previous behavior by default). (contributed by LindyHopperGT)
• Added the bExactMatch option to Notify Actor node. (contributed by bohdon)
• Timer node complete in next tick if value is closer to 0. (contributed by ryanjon2040)
• Added search keywords to nodes: AND, Checkpoint, Log, Multi Gate, NotifyActor, OnActorRegistered, OnActorUnregistered, OR, Timer. (contributed by ryanjon2040)
• (UE 5.1+) Fixed applying FMovieSceneSequencePlaybackSettings while creating UFlowLevelSequencePlayer. (contributed by michalmocarskiintermarum)
• Fixed: Component Observer may continue triggering outputs if the last component triggered a finish during UFlowNode_ComponentObserver::StartObserving. (fix proposed by lfowles)

Flow Component

• Fixed bug in UFlowComponent::GetRootInstances() where the Owner parameter wasn't being used. (contributed by LindyHopperGT)

SaveGame support

• Exposed methods to blueprints: LoadRootFlow, LoadSubFlow. (contributed by Mephiztopheles)
• Fixed rare issue with loading saves: prevent triggering input on a not-yet-loaded node. Now when restoring the graph state, we iterate the graph "from the end", backward to execution order. This prevents issue when the preceding node would instantly fire output to a not-yet-loaded node.

Asset Search

• Jump from the Asset Search result to the Flow Node in any graph editor. To unlock this feature
  • Integrate this pull request to your engine: Jump from Asset Search result to the node in any graph editor!.
  • Set the ENABLE_JUMP_TO_INNER_OBJECT value to 1.
• Added option to run a search on a single asset, with Search Browser opened as an asset editor tab. To unlock this feature
  • Integrate this pull request to your engine: Asset Search: added option to run a search on a single asset, with Search Browser opened as asset editor tab
  • Set the ENABLE_SEARCH_IN_ASSET_EDITOR value to 1.

Runtime misc

• Added null UFlowAsset check when calling UFlowSubsystem::StartRootFlow. (contributed by bohdon)
• Changed some functions to return const &'s rather than doing a full deep copy of a member container. (contributed by LindyHopperGT)
• Added includes and forward declaration fixing some compiler errors. (contributed by LindyHopperGT)

Editor misc

• Compilation-breaking change for C++: Context Pins now are constructed directly as FFlowPin instead of FName. It allows setting display names and tooltips on such pins.
• Extending the GetAssignedGraphNodeClass() function to support returning the correct EdGraphNode for grandchild classes of UFlowNode. (contributed by Vi-So)
• Show a pretty readable pin name even if a friendly name is not provided. This is optional behavior that might be enabled by the bEnforceFriendlyPinNames flag in editor settings. (based on ryanjon2040 contribution)
• Extracted graph-related code from the FFlowAssetEditor to the new SFlowGraphEditor class.
• Added SFlowGraphEditor::IsTabFocused method to prevent delete/paste/copy nodes if the graph tab isn't focused.
• Exposed all remaining classes out of the module, allowing you to extend whatever you need.
• Moved MovieScene headers to the Public folder. Moved the SLevelEditorFlow class to the Utils folder.
• Moved all Details Customizations classes to a single DetailsCustomizations folder.

New: Import from blueprint graph

• Added UFlowImportUtils blueprint library to create Flow Graph asset in the same folder as the selected blueprint.
• Includes simple utility method that recreates Flow Graph with nodes matching blueprint function nodes (UK2Node_CallFunctions).
• Utility automatically transfers blueprint input pin values to Flow Node properties if the pin name matches the Flow Node property name. It's also possible to map mismatched names (blueprint pin to Flow Node property) as the utility input parameter.
• Added UFlowNode::PostImport() allowing to update a newly created Flow Node just after it got created.

NOTE. It's NOT meant to be the universal, out-of-box solution as the complexity of blueprint graphs conflicts with the simplicity of the Flow Graph. However, it might be useful to provide this basic utility to anyone who would like to batch-convert their custom blueprint-based event system to Flow Graph.