NiagaraDebugHud

NiagaraDebugHud

#Overview

name: NiagaraDebugHud

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

• type: Cmd
• help: Shorter version to quickly toggle debug hud modes\n No value will toggle the overview on / off\n A numberic value selects which overmode to set, where 0 is off\n

It is referenced in 5 C++ source files.

#Summary

#Usage in the C++ source code

The purpose of NiagaraDebugHud is to provide a debugging and visualization tool for the Niagara visual effects system in Unreal Engine 5. It allows developers to view and analyze real-time information about Niagara systems and their performance.

This setting variable is primarily used by the Niagara plugin, which is part of Unreal Engine’s visual effects subsystem. Based on the callsites, it’s clear that the NiagaraWorldManager class is the main component that interacts with and manages the NiagaraDebugHud.

The value of this variable is set in the FNiagaraWorldManager::Init function, where a new FNiagaraDebugHud object is created and assigned to the NiagaraDebugHud unique pointer.

NiagaraDebugHud interacts with other components of the Niagara system, particularly the NiagaraWorldManager. It’s used to gather system information in the PostActorTick function of NiagaraWorldManager.

Developers should be aware that:

1. The NiagaraDebugHud is only available when WITH_NIAGARA_DEBUGGER is defined, indicating it’s a debugging feature that may not be present in all builds.
2. It’s accessed through the NiagaraWorldManager, which suggests it operates on a per-world basis.
3. There’s a console command “NiagaraDebugHud” that can be used to toggle and control the debug HUD modes.

Best practices when using this variable include:

1. Use it primarily for debugging and performance analysis, not for gameplay-critical features.
2. Be mindful of its performance impact, especially when gathering system info in the PostActorTick function.
3. Utilize the console command for quick toggles and mode changes during development and testing.
4. Remember to disable or remove debug-related code in release builds to optimize performance.

#References in C++ code

#Callsites

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

#Loc: <Workspace>/Engine/Plugins/FX/Niagara/Source/Niagara/Private/NiagaraDebugHud.cpp:168

Scope (from outer to inner):

file
namespace    NiagaraDebugLocal

Source code excerpt:

	static FAutoConsoleCommandWithWorldAndArgs CmdNiagaraDebugHud(
		TEXT("NiagaraDebugHud"),
		TEXT("Shorter version to quickly toggle debug hud modes\n")
		TEXT(" No value will toggle the overview on / off\n")
		TEXT(" A numberic value selects which overmode to set, where 0 is off\n"),
		FConsoleCommandWithWorldAndArgsDelegate::CreateLambda(
			[](const TArray<FString>& Args, UWorld*)
			{

#Loc: <Workspace>/Engine/Plugins/FX/Niagara/Source/Niagara/Private/NiagaraWorldManager.cpp:402

Scope (from outer to inner):

file
function     void FNiagaraWorldManager::Init

Source code excerpt:

#if WITH_NIAGARA_DEBUGGER
	NiagaraDebugHud.Reset(new FNiagaraDebugHud(World));
#endif
#if WITH_NIAGARA_LEAK_DETECTOR
	if ( World->IsGameWorld() )
	{
		ComponentLeakDetector.Reset(new FNiagaraComponentLeakDetector());
	}

#Loc: <Workspace>/Engine/Plugins/FX/Niagara/Source/Niagara/Private/NiagaraWorldManager.cpp:1111

Scope (from outer to inner):

file
function     void FNiagaraWorldManager::PostActorTick

Source code excerpt:

#if WITH_NIAGARA_DEBUGGER
	// Tick debug HUD for the world
	if (NiagaraDebugHud != nullptr)
	{
		QUICK_SCOPE_CYCLE_COUNTER(STAT_NiagaraDebugHUD);
		NiagaraDebugHud->GatherSystemInfo();
	}
#endif

	if ( DebugPlaybackMode == ENiagaraDebugPlaybackMode::Step )
	{
		RequestedDebugPlaybackMode = ENiagaraDebugPlaybackMode::Paused;

#Loc: <Workspace>/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraWorldManager.h:228

Scope (from outer to inner):

file
class        class FNiagaraWorldManager : public FGCObject
function     class FNiagaraDebugHud* GetNiagaraDebugHud

Source code excerpt:

#if WITH_NIAGARA_DEBUGGER
	class FNiagaraDebugHud* GetNiagaraDebugHud() { return NiagaraDebugHud.Get(); }
#endif

	class FNiagaraDeferredMethodQueue& GetDeferredMethodQueue() { return DeferredMethods; }

	/**
	Flush the compute simulation queue and any deferred actions.

#Loc: <Workspace>/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraWorldManager.h:411

Scope (from outer to inner):

file
class        class FNiagaraWorldManager : public FGCObject

Source code excerpt:

#if WITH_NIAGARA_DEBUGGER
	TUniquePtr<class FNiagaraDebugHud> NiagaraDebugHud;
#endif
#if WITH_NIAGARA_LEAK_DETECTOR
	TUniquePtr<class FNiagaraComponentLeakDetector> ComponentLeakDetector;
#endif

	TMap<TObjectPtr<UNiagaraSystem>, TObjectPtr<UNiagaraCullProxyComponent>> CullProxyMap;