1. Epic GamesDeveloper
  3. FStateTreeExecutionContext

FStateTreeExecutionContext

StateTree Execution Context is a helper that is used to update and access StateTree instance data.

API > API/Plugins > API/Plugins/StateTreeModule

Inheritance Hierarchy

References

   
Module StateTreeModule
Header /Engine/Plugins/Runtime/StateTree/Source/StateTreeModule/Public/StateTreeExecutionContext.h
Include #include "StateTreeExecutionContext.h"

Syntax

struct FStateTreeExecutionContext

Remarks

StateTree Execution Context is a helper that is used to update and access StateTree instance data.

The context is meant to be temporary, you should not store a context across multiple frames.

The owner is used as the owner of the instantiated UObjects in the instance data and logging, it should have same or greater lifetime as the InstanceData.

In common case you can use the constructor or Init() to initialize the context: FStateTreeExecutionContext Context(*GetOwner(), *StateTreeRef.GetStateTree(), InstanceData); if (SetContextRequirements(Context)) { Context.Tick(DeltaTime); }

bool UMyComponent::SetContextRequirements(FStateTreeExecutionContext& Context) { if (!Context.IsValid()) { return false; } // Setup context data return true; }

Variables

  Type Name Description
Protected variable bool bAllowDirectTransitions True if transitions are allowed to be requested directly instead of buffering.
Protected variable FStateTreeStateHandle CurrentlyProcessedState Current state we're processing, or invalid if not applicable.
Protected variable TArray< FStateTreeDataView, TConcurrentLinearArrayAllocator< FDefaultBlockAllocationTag > > DataViews Array of data pointers (external data, tasks, evaluators, conditions), used during evaluation.
Protected variable TArray< FStateTreeEvent, TConcurrentLinearArrayAllocator< FDefaultBlockAllocationTag > > EventsToProcess Events to process in current tick.
Protected variable FStateTreeInstanceData & InstanceData Instance data used during current tick.
Protected variable FStateTreeTransitionResult NextTransition Next transition, used by RequestTransition().
Protected variable FStateTreeTransitionSource NextTransitionSource Structure describing the origin of the state transition that caused the state change.
Protected variable UObject & Owner Owner of the instance data.
Protected variable TSharedPtr< FStateTreeInstanceData > SharedInstanceData Shared instance data for the duration of the context.
Protected variable const UStateTree & StateTree The StateTree asset the context is initialized for

Constructors

  Type Name Description
Public function  

FStateTreeExecutionContext ( UObject& InOwner,
const UStateTree& InStateTree,
FStateTreeInstanceData& InInstanceData
)

  

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Public function Const bool  
Protected function Virtual void Callback when delayed transition is triggered.
Protected function Const FString  
Protected function Const FString

DebugGetStatePath ( const FStateTreeActiveStates& ActiveStates,
const int32 ActiveStateIndex
)

  
Public function void  
Protected function EStateTreeRunStatus

EnterState ( const FStateTreeTransitionResult& Transition
)

 Handles logic for entering State.
Protected function void

ExitState ( const FStateTreeTransitionResult& Transition
)

 Handles logic for exiting State.
Public function Const void

ForEachEvent ( TFunc&& Function
)

 Iterates over all events.
Public function Const FString  
Public function Const TArray< FName >  
Public function Const const FStateTreeActiveStates &  
Public function Const TConstArrayView< FStateTreeExternalDataDesc >  
Public function Const FStateTreeStateHandle  
Public function Const const FStateTreeEventQueue &  
Public function Const TConstArrayView< FStateTreeEvent >  
Protected function Const const FStateTreeExecutionState &  
Protected function FStateTreeExecutionState &  
Public function Const T::DataType &

GetExternalData ( const T Handle
)

 Returns reference to external data based on provided handle.
Public function Const TConstArrayView< FStateTreeExternalDataDesc >  
Public function Const FStateTreeExternalDataHandle  
Public function Const T::DataType *

GetExternalDataPtr ( const T Handle
)

 Returns pointer to external data based on provided item handle.
Public function FStateTreeDataView  
Public function Const const FStateTreeInstanceData *  
Public function Const T &  
Public function Const T::FInstanceDataType &

GetInstanceData ( const T& Node
)

  
Public function Const T *  
Public function Const TStateTreeInstanceDataStructRef< typename T::FInstanceDataType >

GetInstanceDataStructRef ( const T& Node
)

  
Protected function Virtual Const FString  
Public function Const EStateTreeRunStatus  
Public function Const FStateTreeEventQueue &  
Public function Const FStateTreeInstanceData * Mutable references to the instance data in use, or nullptr if the context is not valid.
Public function Const UObject *  
Protected function Const FStateTreeStateHandle

GetParentLinkedStateHandle ( const FStateTreeActiveStates& ActiveStates,
const FStateTreeStateHandle StartStateHandle
)

  
Protected function Const FStateTreeStateHandle

GetParentLinkedStateHandle ( const FStateTreeActiveStates& ActiveStates,
const int32 StartStateIndex
)

 Traverses the ActiveStates from StartStateIndex to 0 and returns first linked state.
Protected function Const FString  
Public function Const int32  
Public function Const const FCompactStateTreeState *  
Protected function Const FString  
Public function Const const UStateTree *  
Public function Const EStateTreeRunStatus  
Public function Const UWorld *  
Public function Const bool  
Public function Const bool

IsValid ()

  
Protected function bool Requests transition to a specified state with specified priority.
Public function void Requests transition to a state.
Protected function bool

SelectState ( const FStateTreeStateHandle NextState,
FStateTreeActiveStates& OutNewActiveStates,
FStateTreeActiveStates& VisitedStates
)

 Runs state selection logic starting at the specified state, walking towards the leaf states.
Protected function bool

SelectStateInternal ( const FStateTreeStateHandle NextState,
FStateTreeActiveStates& OutNewActiveStates,
FStateTreeActiveStates& VisitedStates
)

 Used internally to do the recursive part of the SelectState().
Public function Const void

SendEvent ( const FGameplayTag Tag,
const FConstStructView Payload,
const FName Origin
)

 Sends event for the StateTree.
Public function void Updates data view of the parameters by using the default values defined in the StateTree asset.
Public function void Sets external data view value for specific item.
Protected function void

SetNodeDataView ( T& Node,
int32& InstanceStructIndex,
int32& InstanceObjectIndex
)

 Helper function to update struct or object dataview of a node.
Public function void

SetParameters ( const FInstancedPropertyBag& Parameters
)

 Updates data view of the parameters by replacing the default values defined in the StateTree asset by the provided values.
Public function EStateTreeRunStatus

Start ()

 Start executing.
Protected function EStateTreeRunStatus

StartEvaluatorsAndGlobalTasks ( FStateTreeIndex16& OutLastInitializedTaskIndex
)

 Starts evaluators and global tasks.
Protected function void Handles logic for signalling State completed.
Public function EStateTreeRunStatus

Stop ( const EStateTreeRunStatus CompletionStatus
)

 Stop executing if the tree is running.
Protected function void

StopEvaluatorsAndGlobalTasks ( const EStateTreeRunStatus CompletionStatus,
const FStateTreeIndex16 LastInitializedTaskIndex
)

 Stops evaluators and global tasks.
Protected function bool

TestAllConditions ( const int32 ConditionsOffset,
const int32 ConditionsNum
)

 Checks all conditions at given range
Public function EStateTreeRunStatus

Tick ( const float DeltaTime
)

 Tick the state tree logic.
Protected function EStateTreeRunStatus

TickEvaluatorsAndGlobalTasks ( const float DeltaTime,
bool bTickGlobalTasks
)

 Tick evaluators and global tasks by delta time.
Protected function EStateTreeRunStatus

TickTasks ( const float DeltaTime
)

 Ticks tasks of all active states starting from current state by delta time.
Protected function bool Triggers transitions based on current run status.
Protected function void

UpdateInstanceData ( const FStateTreeActiveStates& CurrentActiveStates,
const FStateTreeActiveStates& NextActiveStates
)

  
Protected function void

UpdateLinkedStateParameters ( const FCompactStateTreeState& State,
const int32 ParameterInstanceIndex
)

 Sets up parameter data view for a linked state and copies bound properties.
Protected function void Sets up parameter data view for subtree state.

Classes

  Type Name Description
Protected struct FAllowDirectTransitionsScope Helper struct to track when it is allowed to request transitions.  
Protected struct FCurrentlyProcessedStateScope Helper struct to track currently processed state.  

Deprecated Functions

  Type Name Description
Protected function Virtual void Use BeginDelayedTransition() instead.
Public function Const void

SendEvent ( const FStateTreeEvent& Event
)

 Use AddEvent() with individual parameters instead.

Ask questions and help your peers Developer Forums

Write your own tutorials or read those from others Learning Library

On this page