AbilitySystem.UpdateMontageSectionIdToPlay

AbilitySystem.UpdateMontageSectionIdToPlay

#Overview

name: AbilitySystem.UpdateMontageSectionIdToPlay

This variable is created as a Console Variable (cvar).

It is referenced in 3 C++ source files.

#Summary

#Usage in the C++ source code

The purpose of AbilitySystem.UpdateMontageSectionIdToPlay is to control whether the section ID for replicated montages should be updated during tick. This setting variable is part of the Gameplay Ability System (GAS) in Unreal Engine 5, specifically related to animation montage replication.

This setting variable is primarily used in the GameplayAbilities plugin, which is a core component of the Ability System in Unreal Engine. The subsystem that relies on this variable is the AbilitySystemComponent, which is responsible for managing and executing gameplay abilities.

The value of this variable is set as a console variable (CVar) with a default value of true. It can be changed at runtime through console commands or programmatically.

The associated variable CVarUpdateMontageSectionIdToPlay interacts directly with this setting. It’s a TAutoConsoleVariable that holds the actual value of the setting.

Developers must be aware that this variable affects how montage section IDs are updated and replicated. When set to true, it ensures that the section ID for replicated montages is updated during the tick, which can be crucial for maintaining synchronization between server and client in multiplayer games.

Best practices when using this variable include:

  1. Understand the implications of enabling or disabling this feature on your game’s networking and animation synchronization.
  2. Test your game thoroughly with both true and false values to ensure proper behavior in all scenarios.
  3. Consider exposing this setting in your game’s options menu if you want to give advanced users control over this behavior.
  4. Monitor performance impacts, especially in network-intensive situations, as frequent updates might increase network traffic.

Regarding the associated variable CVarUpdateMontageSectionIdToPlay:

The purpose of CVarUpdateMontageSectionIdToPlay is to provide a runtime-configurable way to enable or disable the updating of montage section IDs during tick.

This variable is used directly in the AbilitySystemComponent, specifically in the AnimMontage_UpdateReplicatedData function. When its value is true, it updates the SectionIdToPlay in the OutRepAnimMontageInfo structure.

The value of this variable is set at initialization and can be changed at runtime through console commands.

It interacts closely with the animation system, particularly with AnimInstance and montage playback.

Developers should be aware that changing this variable’s value can affect how montage sections are replicated and played on remote clients. It’s particularly important for ensuring smooth and accurate animation playback in networked environments.

Best practices for using this variable include:

  1. Thoroughly test your game’s animation behavior with this variable both enabled and disabled.
  2. Consider the network implications of frequent updates if this is set to true.
  3. Use this in conjunction with other animation and networking settings to achieve the desired balance between accuracy and performance.
  4. Document any changes to this variable’s default value in your project, as it may affect how other developers work with the animation system.

#References in C++ code

#Callsites

This variable is referenced in the following C++ source code:

#Loc: <Workspace>/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Private/AbilitySystemComponent_Abilities.cpp:49

Scope: file

Source code excerpt:

static TAutoConsoleVariable<bool> CVarAbilitySystemSetActivationInfoMultipleTimes(TEXT("AbilitySystem.SetActivationInfoMultipleTimes"), false, TEXT("Set this to true if some replicated Gameplay Abilities aren't setting their owning actors correctly"));
static TAutoConsoleVariable<bool> CVarGasFixClientSideMontageBlendOutTime(TEXT("AbilitySystem.Fix.ClientSideMontageBlendOutTime"), true, TEXT("Enable a fix to replicate the Montage BlendOutTime for (recently) stopped Montages"));
static TAutoConsoleVariable<bool> CVarUpdateMontageSectionIdToPlay(TEXT("AbilitySystem.UpdateMontageSectionIdToPlay"), true, TEXT("During tick, update the section ID that replicated montages should use"));
static TAutoConsoleVariable<bool> CVarReplicateMontageNextSectionId(TEXT("AbilitySystem.ReplicateMontageNextSectionId"), true, TEXT("Apply the replicated next section Id to montages when skipping position replication"));
static TAutoConsoleVariable<bool> CVarEnsureAbilitiesEndGracefully(TEXT("AbilitySystem.EnsureAbilitiesEndGracefully"), true, TEXT("When shutting down (during ClearAllAbilities) we should check if all GameplayAbilities gracefully ended. This should be disabled if you have NonInstanced abilities that are designed for multiple concurrent executions."));

void UAbilitySystemComponent::InitializeComponent()
{
	Super::InitializeComponent();

#Associated Variable and Callsites

This variable is associated with another variable named CVarUpdateMontageSectionIdToPlay. They share the same value. See the following C++ source code.

#Loc: <Workspace>/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Private/AbilitySystemComponent_Abilities.cpp:49

Scope: file

Source code excerpt:

static TAutoConsoleVariable<bool> CVarAbilitySystemSetActivationInfoMultipleTimes(TEXT("AbilitySystem.SetActivationInfoMultipleTimes"), false, TEXT("Set this to true if some replicated Gameplay Abilities aren't setting their owning actors correctly"));
static TAutoConsoleVariable<bool> CVarGasFixClientSideMontageBlendOutTime(TEXT("AbilitySystem.Fix.ClientSideMontageBlendOutTime"), true, TEXT("Enable a fix to replicate the Montage BlendOutTime for (recently) stopped Montages"));
static TAutoConsoleVariable<bool> CVarUpdateMontageSectionIdToPlay(TEXT("AbilitySystem.UpdateMontageSectionIdToPlay"), true, TEXT("During tick, update the section ID that replicated montages should use"));
static TAutoConsoleVariable<bool> CVarReplicateMontageNextSectionId(TEXT("AbilitySystem.ReplicateMontageNextSectionId"), true, TEXT("Apply the replicated next section Id to montages when skipping position replication"));
static TAutoConsoleVariable<bool> CVarEnsureAbilitiesEndGracefully(TEXT("AbilitySystem.EnsureAbilitiesEndGracefully"), true, TEXT("When shutting down (during ClearAllAbilities) we should check if all GameplayAbilities gracefully ended. This should be disabled if you have NonInstanced abilities that are designed for multiple concurrent executions."));

void UAbilitySystemComponent::InitializeComponent()
{
	Super::InitializeComponent();

#Loc: <Workspace>/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Private/AbilitySystemComponent_Abilities.cpp:3072

Scope (from outer to inner):

file
function     void UAbilitySystemComponent::AnimMontage_UpdateReplicatedData

Source code excerpt:

		{
			constexpr bool bForceGameThreadValue = true;
			if (CVarUpdateMontageSectionIdToPlay.GetValueOnAnyThread(bForceGameThreadValue))
			{
				OutRepAnimMontageInfo.SectionIdToPlay = uint8(CurrentSectionID + 1);
			}

			int32 NextSectionID = AnimInstance->Montage_GetNextSectionID(LocalAnimMontageInfo.AnimMontage, CurrentSectionID);
			if (NextSectionID >= (256 - 1))