replay.MontageErrorThreshold
replay.MontageErrorThreshold
#Overview
name: replay.MontageErrorThreshold
This variable is created as a Console Variable (cvar).
- type:
Var - help:
Tolerance level for when montage playback position correction occurs in replays
It is referenced in 3 C++ source files.
#Summary
#Usage in the C++ source code
The purpose of replay.MontageErrorThreshold is to set the tolerance level for montage playback position correction during replays in Unreal Engine’s Gameplay Ability System.
This setting variable is primarily used by the Gameplay Abilities plugin, which is part of Unreal Engine’s animation and gameplay systems. It specifically relates to the replication and synchronization of animation montages during gameplay replays.
The value of this variable is set through a console variable (CVar) named CVarReplayMontageErrorThreshold. It’s initialized with a default value of 0.5f, but can be adjusted at runtime through console commands or game code.
The associated variable CVarReplayMontageErrorThreshold directly interacts with replay.MontageErrorThreshold. They share the same value and purpose.
Developers must be aware that this variable only affects montage playback during replays, not during normal gameplay. It determines how much discrepancy is allowed between the expected and actual montage playback positions before a correction is applied.
Best practices when using this variable include:
- Adjusting the value based on the specific needs of your game. A lower value will result in more frequent corrections but potentially smoother playback, while a higher value might reduce network traffic but could lead to more noticeable jumps in animation.
- Testing thoroughly with different network conditions to find the optimal balance between smooth playback and network performance.
- Consider exposing this setting to players or QA testers to fine-tune based on different hardware and network environments.
Regarding the associated variable CVarReplayMontageErrorThreshold:
- It’s a TAutoConsoleVariable
, which means it can be adjusted at runtime through console commands. - It’s used in the UAbilitySystemComponent::OnRep_ReplicatedAnimMontage function to determine the error threshold for montage replication during replays.
- When not in replay mode, a fixed value of 0.1f is used instead.
- Developers should be aware that changes to this variable will immediately affect all replay playbacks, so it should be adjusted carefully and with consideration for the player experience.
#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:46
Scope: file
Source code excerpt:
CSV_DECLARE_CATEGORY_MODULE_EXTERN(CORE_API, Basic);
static TAutoConsoleVariable<float> CVarReplayMontageErrorThreshold(TEXT("replay.MontageErrorThreshold"), 0.5f, TEXT("Tolerance level for when montage playback position correction occurs in replays"));
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."));
#Associated Variable and Callsites
This variable is associated with another variable named CVarReplayMontageErrorThreshold. They share the same value. See the following C++ source code.
#Loc: <Workspace>/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Private/AbilitySystemComponent_Abilities.cpp:46
Scope: file
Source code excerpt:
CSV_DECLARE_CATEGORY_MODULE_EXTERN(CORE_API, Basic);
static TAutoConsoleVariable<float> CVarReplayMontageErrorThreshold(TEXT("replay.MontageErrorThreshold"), 0.5f, TEXT("Tolerance level for when montage playback position correction occurs in replays"));
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."));
#Loc: <Workspace>/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Private/AbilitySystemComponent_Abilities.cpp:3133
Scope (from outer to inner):
file
function void UAbilitySystemComponent::OnRep_ReplicatedAnimMontage
Source code excerpt:
const bool bIsPlayingReplay = World && World->IsPlayingReplay();
const float MONTAGE_REP_POS_ERR_THRESH = bIsPlayingReplay ? CVarReplayMontageErrorThreshold.GetValueOnGameThread() : 0.1f;
UAnimInstance* AnimInstance = AbilityActorInfo.IsValid() ? AbilityActorInfo->GetAnimInstance() : nullptr;
if (AnimInstance == nullptr || !IsReadyForReplicatedMontage())
{
// We can't handle this yet
bPendingMontageRep = true;