Developer Library

Base:

UBlueprintFunctionLibrary

Type:

UNDeveloperLibrary

Header File:

NexusCore/Public/Developer/NDeveloperLibrary.h

A small collection of functionality to wrap the usage of developer tools.

UFunctions

Debug

Get UObject Count

/**
  * Gets the current number of known UObjects by looking at the global UObject array and subtracting the number of available spots.
  * @return The number of objects.
  */
static int32 GetCurrentObjectCount() { return FNDeveloperUtils::GetCurrentObjectCount(); };

Snapshots

Create UObject Snapshot

Captures a minimal data structure (FNObjectSnapshotEntry) about all currently known UObjects, recording:

info

If you are just looking to capture the current state of things to a file check out the N.Developer.Snapshot console command.

• Serial number
• Number of references
• Is it flagged for Garbage Collection?
• Is it part of a root set?
• It's name and full name where possible.
• A TWeakObjectPtr to the object.

warning

This process can cause a bit of a performance hit depending on the number of objects that you have currently created.

/**
  * Captures a minimal data structure about all currently known UObjects.
  * @return The FNObjectSnapshot recording structure.
  */
static FNObjectSnapshot CreateObjectSnapshot() { return FNObjectSnapshotUtils::Snapshot(); }

Create UObject Snapshot Diff

Compares two already created FNObjectSnapshots to formulate a difference report of what changed.

warning

This process can cause a bit of a performance hit as it will itterate over potentially a large array of FNObjectSnapshotEntry.

/**
  * Compares two already created snapshots to formulate a difference report of what changed.
  * @param OldSnapshot Original FNObjectSnapshot created as the baseline.
  * @param NewSnapshot The FNObjectSnapshot to compare the baseline against.
  * @param bRemoveKnownLeaks Should known objects that leak be removed from tracking.
  * @return A FNObjectSnapshotDiff structure outlining the differences.
  */
static FNObjectSnapshotDiff CreateSnapshotDiff(const FNObjectSnapshot& OldSnapshot, const FNObjectSnapshot& NewSnapshot, const bool bRemoveKnownLeaks = false)
{
  return FNObjectSnapshotUtils::Diff(OldSnapshot, NewSnapshot, bRemoveKnownLeaks);
}

Get UObject Snapshot Entry Summary

/**
  * Get an output-friendly string from an FNObjectSnapshotEntry.
  * @param Entry The entry to generate a string from.
  * @return The output-friendly string.
  */
static FString GetObjectSnapshotEntrySummary(const FNObjectSnapshotEntry& Entry) { return Entry.ToString(); }

Snapshot Entry Line

(0) [R] [G] Package /Script/DeveloperSettings

Reference Count	Is Root Set?	Is Flagged For GC?	FullName
(0)	[R]	[G]	Package /Script/DeveloperSettings

info

The Reference Count does not always seem to be accurate as polled from the UObject, and the FullName is replaced with the FName if the UObject is no longer valid.

Get UObject Snapshot Summary

Get an output-friendly FString that summarizes the contents of a FNObjectSnapshot.

Example Content

Captured %i Objects (%i Untracked)

/**
  * Get an output-friendly string that summarizes the contents of an FNObjectSnapshot.
  * @param Snapshot The snapshot to generate a string from.
  * @return The output-friendly string.
  */

Get UObject Snapshot Detailed Summary

/**
  * Get an output-friendly string that provides a more in-depth output detailing the contents of an FNObjectSnapshot.
  * @param Snapshot The snapshot to generate a detailed string from.
  * @return The output-friendly string.
  */	
static FString GetObjectSnapshotDetailedSummary(const FNObjectSnapshot& Snapshot) { return Snapshot.ToDetailedString(); }

Example Content

Captured %i Objects (%i Untracked)
...

Get UObject Snapshot Diff Summary

Get an output-friendly FString that summarizes the number of changes found in a FNObjectSnapshotDiff.

Example Content

Total %i (%i Changes | %i Previously Untracked | %i Currently Untracked) - Added %i / Maintained %i / Removed %i

/**
  * Get an output-friendly string that summarizes the contents of an FNObjectSnapshotDiff.
  * @param Diff The FNObjectSnapshotDiff to generate a string from.
  * @return The output-friendly string.
  */
static FString GetObjectSnapshotDiffSummary(const FNObjectSnapshotDiff& Diff) { return Diff.ToString(); }

Get UObject Snapshot Diff Detailed Summary

Get an output-friendly FString that contains a list of all changes found in an FNObjectSnapshotDiff in a formatted manner.

Example Content

Captured %i Objects (%i Changes)
Previously %i Untracked Objects | Currently %i Untracked Objects
Added (%i):
...
Maintained (%i)
...
Removed (%i):
...

/**
  * Get an output-friendly string that provides a more in-depth output detailing the contents of an FNObjectSnapshotDiff.
  * @param Diff The FNObjectSnapshotDiff to generate a detailed string from.
  * @return The output-friendly string.
  */	
static FString GetObjectSnapshotDiffDetailedSummary(const FNObjectSnapshotDiff& Diff) { return Diff.ToDetailedString(); }

Output Snapshot To Log

Simple way to output the contents of a FNOjectSnapshotDiff to LogNexus.

Example Log Output

[FNObjectSnapshotDiff::DumpToLog] Captured %i Objects (%i Changes)
Previously %i Untracked Objects | Currently %i Untracked Objects
Added (%i):
...
Maintained (%i)
...
Removed (%i):
...

/**
  * Output an FNObjectSnapshotDiff's detailed summary to LogNexus.
  * @param Diff The FNObjectSnapshotDiff to generate output from.
  */
static void DumpSnapshotDiffToLog(const FNObjectSnapshotDiff& Diff) { Diff.DumpToLog(); }

Drawing

Draw Debug String🚧0.3.0🚧

Renders a FString in the UWorld via a pseudo DebugDrawLine utiling the FNPrimitiveFont.

/**
  * Draw a string via ULineBatchComponent.
  * @param WorldContextObject Object that provides the context of which world to operate in.
  * @param String The string to draw out.
  * @param Position The world position to start drawing the string at.
  * @param Rotation The world rotation to apply to the drawing, the base orientation is backwards facing. 
  * @param bPersistentLines Should the drawn lines be permanent?
  * @param LifeTime How long should the lines last if not permanent?
  * @param DepthPriority What priority should they be drawn at?
  * @param ForegroundColor The color to use when drawing the lines for the string.
  * @param Scale The multiplier to apply to glyph size.
  * @param LineHeight The height used to represent a line.
  * @param Thickness The thickness of the lines used to draw glyphs.
  * @param bInvertLineFeed Should new lines be stacked on top of older lines?
  * @param bDrawBelowPosition Should the top of the first line align with the position?
  */
static void DrawDebugString(const UObject* WorldContextObject, FString String, const FVector Position,
  const FRotator Rotation, const bool bPersistentLines = false, const float LifeTime=-1.f, const uint8 DepthPriority = 0,
  const FLinearColor ForegroundColor = FLinearColor::White, const float Scale = 1,
  const float LineHeight = 4.f, const float Thickness = 8.f, const bool bInvertLineFeed = false,
  const bool bDrawBelowPosition = true)
{
  const UWorld* InWorld = GEngine->GetWorldFromContextObject(WorldContextObject, EGetWorldErrorMode::ReturnNull);
  if (InWorld == nullptr) return;
  FNDrawDebugHelpers::DrawDebugString(InWorld, String, Position, Rotation, bPersistentLines, LifeTime, 
    DepthPriority, ForegroundColor, Scale, LineHeight, Thickness, bInvertLineFeed, bDrawBelowPosition);		
}