Technical reference for the CCS debug tools introduced alongside showdebug camera. See User Guide → Debugging for a workflow-oriented introduction.

Debug Panel (FComposableCameraDebugPanel)¶

Activation¶

CCS.Debug.Panel 1      ← enable
CCS.Debug.Panel 0      ← disable (default)

Implemented by FComposableCameraDebugPanel. Renders via UDebugDrawService's "Game" channel as a static delegate registered at module startup (FComposableCameraSystemModule::StartupModule). While disabled the draw function reads the CVar and early-outs immediately — no meaningful cost.

Available in Debug, Development, and Test builds. Stripped entirely in Shipping (#if !UE_BUILD_SHIPPING).

Regions¶

The panel paints five regions top-to-bottom. All data comes from BuildDebugSnapshot calls on the context stack and director — the same pipeline that backs showdebug camera and the dump commands.

Current Pose¶

The PCM's final output this frame, rendered in a two-column, four-group layout.

Physical group data sources¶

The Physical group has three rendering modes depending on what's available:

The CineCamera fallback exists because UComposableCameraViewTargetProxyNode (used in the Sequencer LS path) writes only transform + FOV + PostProcess into the pose — it never populates the discrete Aperture / Focus / ISO / Shutter / Sensor slots. Without the fallback, the Physical group showed Status: off in LS mode even when the CineCamera had real DoF and exposure settings.

Below the numeric fields: a pose-history sparkline backed by FComposableCameraPoseHistoryEntry ring buffer (120 entries, ~48 B each, ~6 KB total per PCM). The ring buffer records GameTime from UWorld::GetTimeSeconds, so it pauses with the game during Time Dilation / pause — the timeline stays coherent when scrubbing history during a paused PIE session. Context-switch markers are vertical lines drawn wherever ContextName changes between adjacent entries.

Context Stack & Evaluation Tree¶

A live tree rendered from FComposableCameraContextStackSnapshot. Contexts appear in stack order (base at bottom, active at top). Each context expands its director's evaluation tree, flattened DFS pre-order via FComposableCameraTreeNodeSnapshot.

Tree-node fields used by the renderer:

Reference leaves (ReferenceLeaf kind) inline their referenced director's subtree. The root of that subtree has bIsReferencedRoot = true, which suppresses the [from]/[to] role prefix that would otherwise appear at that boundary (the RefLeaf is a leaf in the outer tree, not a transition parent, so the usual depth-based role inference does not apply).

Running Camera¶

The active context's Director::RunningCamera, if any.

Camera Actions¶

Three-line-per-action view for each entry in PCM::ActiveActions:

Modifiers¶

Structured two-section view:

• Effective (N) — flat list of the per-node-class winning modifier for each camera node. This is the modifier that actually ran.
• All (M) — grouped by CameraTag → NodeClass → entries, with a [*] marker on the entry that won priority resolution in each bucket.

Use "Effective" to confirm a modifier applied at all; use "All" to diagnose why a higher-priority modifier might be losing to another entry.

Warnings (FComposableCameraLogCapture)¶

Log entries captured by FComposableCameraLogCapture, an FOutputDevice registered with GLog at module startup.

What is captured: any log line emitted on LogComposableCameraSystem or LogComposableCameraSystemEditor at Warning verbosity or worse (Warning, Error, Fatal). Log, Display, Verbose, and VeryVerbose are filtered out at capture time.

Ring buffer: 16 entries maximum (FComposableCameraLogCapture::MaxCapturedEntries). Older entries are evicted when the buffer is full.

Deduplication: if the same (Category, Verbosity, Message) triple fires again before the next eviction, the existing entry's RepeatCount is incremented instead of inserting a duplicate. The panel renders "(×N)" when N > 1.

Thread safety: Serialize (the capture hook) can be called from any thread. The ring buffer is guarded by a FCriticalSection; game-thread reads and worker-thread writes serialize cleanly. The lock is held only long enough to update a small fixed-size array.

Build gating: Install / Uninstall / GetRecentEntries are all #if !UE_BUILD_SHIPPING. Shipping builds pay zero cost — no output device registered, no ring buffer allocated, no lock.

Viewport Debug (FComposableCameraViewportDebug)¶

Activation¶

CCS.Debug.Viewport 1                      ← master switch (frustum + per-node gizmos)
CCS.Debug.Viewport 0                      ← off (default)
CCS.Debug.Viewport.AlwaysShow 1           ← force frustum even while possessing
CCS.Debug.Viewport.Nodes.All 1           ← OR-enable all node gizmos
CCS.Debug.Viewport.Transitions.All 1     ← OR-enable all transition gizmos

Per-node gizmos (all default 0):

Rendering pathway¶

Implemented by FComposableCameraViewportDebug. Draws via FTSTicker::GetCoreTicker() delegate, not UDebugDrawService. The ticker fires every frame regardless of which viewport is active; DrawDebug* calls go to the world's LineBatcher, which is rendered by every viewport drawing that world. This is the reason gizmos appear in the editor viewport during F8 eject — UDebugDrawService's "Game" hook does not fire from the editor viewport, which was the blocking issue that motivated the switch to the ticker + line batcher.

Frustum auto-hide¶

The frustum (drawn at the near plane) occludes the scene when the player is viewing through the camera. Auto-hide logic:

• In editor builds: frustum only fires when GEditor->bIsSimulatingInEditor is true (F8 eject / Simulate mode).
• In non-editor builds: frustum always fires when the master CVar is on.
• CCS.Debug.Viewport.AlwaysShow 1: bypasses the auto-hide in editor builds.

ShouldShowAllNodeGizmos / ShouldShowAllTransitionGizmos¶

FComposableCameraViewportDebug::ShouldShowAllNodeGizmos() returns true when CCS.Debug.Viewport.Nodes.All is non-zero. Node callsite idiom:

if (CVarShowMyNodeGizmo.GetValueOnGameThread() == 0 &&
    !FComposableCameraViewportDebug::ShouldShowAllNodeGizmos())
{
    return;
}

OR semantics: either the per-node CVar or the All CVar enables the gizmo. No subtraction; users wanting granularity should leave All off.

DrawSolidDebugSphere¶

Canonical sphere gizmo helper used by every CCS node and transition debug override.

FComposableCameraViewportDebug::DrawSolidDebugSphere(
    World,
    Center,
    Radius,
    Color,          // A is overridden by Alpha param
    Alpha,          // default 100 (≈ 39 %)
    Segments,       // default 12; clamped [4, 32]
    DepthPriority); // 0 = depth-tested; 1 (SDPG_Foreground) = above geometry

All CCS callsites pass SDPG_Foreground so the marker is always visible. The "Solid" name is a historical artifact — the helper renders translucent wireframe rather than a filled mesh, because the engine's hardcoded DebugMeshMaterial depth-tests regardless of DepthPriority, which caused geometry to clip spheres in earlier iterations.

Adding a gizmo to a new node¶

Four steps, ~15 lines total:

1. Override DrawNodeDebug(UWorld*, bool bViewerIsOutsideCamera) in the concrete node class, guarded #if !UE_BUILD_SHIPPING.
2. Declare static TAutoConsoleVariable<int32> CVarShowMyGizmo(TEXT("CCS.Debug.Viewport.MyNode"), 0, ...) in the node's .cpp.
3. Early-out at the top of DrawNodeDebug using the ShouldShowAll OR idiom above.
4. Call DrawDebug* helpers from DrawDebugHelpers.h.

The bViewerIsOutsideCamera parameter is true during F8 eject / Simulate, false during possessed play. Use it to gate gizmos that sit at the camera's own position — drawing a self-collision sphere at the camera origin is only meaningful when the viewer is outside the camera.

Build gating¶

All viewport debug cost is #if !UE_BUILD_SHIPPING. The FTSTicker delegate body compiles to nothing in Shipping builds. Initialize() / Shutdown() and all helper functions are no-ops.

Dump Commands (CCS.Dump.*)¶

Implemented in ComposableCameraDebugDumpCommands.cpp. All commands are registered as FAutoConsoleCommandWithWorldAndArgs at static init time and stripped in Shipping (#if !UE_BUILD_SHIPPING).

Output route: UE_LOG(LogComposableCameraSystem, Display, ...) + FPlatformApplicationMisc::ClipboardCopy(...). The Display verbosity level means the dump appears in Output Log by default, regardless of LogComposableCameraSystem's configured verbosity.

PCM resolution¶

All three commands share the same PCM resolution order:

1. The command-context UWorld (the World the console was invoked from during PIE).
2. Scan GEngine->GetWorldContexts() for the first PIE or Game world with a CCS PCM.

If no PCM is found, the command emits a Warning and returns. This means invoking a dump command from the main editor console before PIE starts will warn rather than crash.

CCS.Dump.Stack¶

No arguments. Dumps UComposableCameraContextStack::BuildDebugSnapshot as indented plain text.

Output structure:

Context Stack (depth: N, pending destroy: M)
-> [N-1] ContextName [active]
      Running Camera: CameraName
      Last Pose: pos=(X, Y, Z)  rot=(P, Y, R)  FOV: F
      Evaluation Tree:
        [Leaf] CameraName
   [N-2] ContextName
      ...
   [pending] ContextName

CCS.Dump.Tree¶

No arguments. Dumps the active director's BuildDebugSnapshot — running camera, last pose, and the flattened evaluation tree for the active context only.

CCS.Dump.Camera [tag]¶

Source-side cameras that are the source (Left) of a mid-transition blend are not included in the scan — they live inside evaluation-tree leaves, not on Director::RunningCamera. This is acceptable for the diagnostic use case; active transitions are visible in CCS.Dump.Stack and CCS.Dump.Tree.

Output structure:

Camera: ActorName
  Class: ClassName
  Tag:   Gameplay.ThirdPerson.Follow
  Pose:  pos=(X, Y, Z)  rot=(P, Y, R)  fov=F
  Lifetime: E / Ts          ← transient cameras only
  Nodes (N, exec order):
    [1] NodeClassName
           PinName              = value
           ...
  Parameters (N):
    ParameterName              = value
    ...
  Variables (N):
    VariableName               = value
    ...
  Data Block: B B (P pins, Q params, R vars, S defaults)

Pin values are formatted via ComposableCameraDebug::AppendOutputPinValue, the same formatter used by the Debug Panel and showdebug camera. (unresolved) means the pin has no offset in the runtime data block — a sync issue between the type asset and the runtime.

Editor Dump Command (CCS.Editor.Dump.Graph)¶

Editor-only command (stripped in Shipping). Available in the editor Output Log console when at least one Camera Type Asset editor is open.

CCS.Editor.Dump.Graph

Iterates every currently-open Camera Type Asset editor via UAssetEditorSubsystem::GetAllEditedAssets() and dumps the full graph state for each asset to LogComposableCameraSystemEditor at Display verbosity and copies the output to the system clipboard.

Contents of each dump:

Primary use case: "graph doesn't save correctly" bug reports. The before/after dump is greppable and diffable, so users can paste it into a GitHub issue without attaching the .uasset binary.

See also¶

• User Guide → Debugging — workflow guide for all four debug surfaces
• ShowDebug reference — section-by-section breakdown of showdebug camera
• Custom Nodes — how to add DrawNodeDebug to a new node
• Profiling & Performance — using debug tools alongside Unreal Insights