Stub and Abandoned Features

Stub & Abandoned Features

Audience: Programmers

Thread Context: Wiring decisions concern lifecycle hooks called from GameplayLifecycleShared.cpp (engine) and EditorUI/EditorApplication (editor), which run on the main thread.

Platform/Backend Scope: Engine-wide, plus editor (SparkEditor/) and game modules. Some stubs are gated behind optional SDKs (OpenXR for VR, Steamworks/EOS for online transports, DirectStorage SDK for fast I/O).

Overview

This is a catalog of features that were "started but abandoned," stubbed (class exists, body is a no-op), or implemented-but-never-wired. It exists so follow-up sessions can systematically resolve each item: wire it in, delete it, or document it as an intentional utility.

The catalog was first compiled on 2026-04-10 from three parallel code audits (Graphics, Engine, Editor/GameModules). Those audits produced several false positives — systems claimed "never referenced" that are actually wired — so every entry here was spot-verified with grep against GameplayLifecycleShared.cpp and the test suite. Many items have since been resolved.

Verification rule: Before acting on any entry, re-run grep for the class name across the whole repo including Tests/, GameModules/, and SparkEditor/. Audit agents historically under-reported references.

Tier 1 — Stub implementations (called, but a no-op or returns false)

These imply a capability the engine does not actually have.

Feature	File	Current Status
VRSystem	Engine/VR/VRSystem.cpp	Still a stub (verified 2026-06-08). Initialize() sets m_initialized = false with the comment "Set to true when OpenXR is linked" and logs a warning. m_runtimeStatus reads "OpenXR runtime not linked in this build (ENABLE_VR currently provides stub backend)." Registered/instantiated, but tracking and rendering are inert until OpenXR is linked.
SteamTransport	Engine/Networking/SteamTransport.h	Still a header-only stub (verified 2026-06-08). A @warning block states "Framework stub — no Steamworks SDK linked." Initialize() always returns false; Send() returns false; Receive() returns -1. NetworkStack::Initialize() still succeeds without it.
OnlineServices — Steam/Epic/Console	Engine/OnlineServices/OnlineServices.h	NullOnlinePlatform works and is wired via OnlineServiceManager. SteamPlatform, EpicPlatform, ConsolePlatform remain declared stubs awaiting their SDKs (documented in header comments).
FoliageSystem / FoliageManager	Graphics/FoliageSystem.h/.cpp	RESOLVED. Full .cpp manager with deterministic scatter, plus a wired render-side consumer: FoliageRenderer (+ Windows variant), FoliageImpostorBaker (+ Windows variant), and FoliageVS/PS.hlsl. FoliageRenderer::GetInstance().Initialize(...) is called in GameplayLifecycleShared.cpp (~line 490), CollectFromFoliageManager(dt) per frame (~line 934), and Shutdown() (~line 1174). The previously-deferred AssetPipeline binding is now done via InstallAssetPipelineLoader(pipeline) (~line 493).

Recommended action: For VR and Steam/Epic/Console — keep documented as stubs awaiting optional SDKs; do not claim them as shipping features. For SteamTransport — delete if no plan, or wire it properly behind the Steamworks SDK.

Tier 2 — Header-only systems with zero engine references

Fully implemented-in-header classes that no .cpp calls. Candidates for deletion unless an owner claims them.

Engine subsystems flagged by the 2026-04 audit

All six entries from the original audit are closed (three were wrong class names, three were wired in with tests) and are no longer tracked here.

Lifecycle registrations removed in the 2026-09 release-readiness sweep

These classes still exist but are no longer initialized, ticked, or shut down by the gameplay lifecycle. Each had a lifecycle Initialize()/Shutdown() pair and no producer or consumer anywhere in production, so the pretend-wiring was removed rather than kept. Resolution path for each: wire a real consumer, or delete. Any wiki page that describes these as active is stale.

Class	Location	Note
OcclusionCullingSystem	Graphics/	No renderer consumes its results.
LightProbeSystem	Graphics/	No probe data reaches a shader.
PipelineStateCache (RHI)	Graphics/RHI/PipelineStateCache.h	GetOrCreate/Invalidate have no callers; D3D11 uses D3D11PipelineStateCache.
TransientResourcePool	Graphics/	No allocation call sites.
VirtualTextureManager	Graphics/	No feedback/page producer.
DynamicQualityScaler	Graphics/	[DynamicQuality] settings are read but nothing scales; see Configuration Reference.
GPUStallProfiler	Graphics/	No query submission.
AsyncComputeScheduler	Graphics/	No dispatch submission.
AIDebugRenderer	Engine/AI/	Tested (Tests/TestAIDebugRendererReal.cpp) but no draw consumer.
HLODSystem	Engine/HLOD/	No renderer consumer; see HLOD and World Partition.
Engine/HotReload/ModuleHotReload singleton	Engine/HotReload/	Duplicate of the live Spark::ModuleHotReloadManager (Core/ModuleHotReload.cpp, polled by the platform frame loops).
Spark::FileLogger + SPARK_FILE_LOG*	Utils/FileLogger.h	Zero production writers; its two lifecycle calls were removed in the 2026-09 sweep. Engine log files come from the Logger FileSink installed by InstallDefaultSinks. Pending wire-it-in-or-delete.
RenderingSettings::occlusionCulling	Core/EngineSettings.h	Setting is still exposed although the implementation behind it is unreachable (see OcclusionCullingSystem above).
ReplicatedFieldSet::WriteDirtyMask/ReadDirtyMask	Engine/Networking/	Not wired into EntityReplicator's serialize/deserialize path (zero callers), so ReadDirtyMask's [[nodiscard]] "abandon the packet" contract is unenforced and untested.
MobilePlatform, RagdollSystem	Engine/Mobile/, Engine/Physics/	Lifecycle comment corrected; deletion routed to their owners.
HybridRTManager on Windows	Graphics/	Only constructed behind an RHI bridge; GraphicsEngine::GetRHIBridge()/GetRHIDevice() are nullptr on Windows (real bridge on Linux), so no hybrid RT runs on the D3D11 path.

Also in this class: AudioMixer::AddBusEffect (per-bus DSP chains) and reverb zones (GetReverbAtPosition) are stored but not applied to any voice. The earlier claim that AudioMixer::CalculateOcclusion / MusicManager::ComputeOcclusion could never report occlusion is retired: both trace WorldStatic hits once a PhysicsSystem is attached (AudioMixer::IsOcclusionAvailable()).

Deleted rather than completed (2026-09 sweep)

Deleted	Why
SparkEditor/Source/Gizmos/GizmoSystem.{h,cpp}	Duplicate of the SceneViewPanel gizmo path, which now ships translate/rotate/scale with one CommandHistory entry per drag.
SparkEditor/Source/Panels/PostProcessingPanel.{h,cpp}	SceneFile-backed editor for a document model the editor no longer builds; use the Inspector's Post-Process Volume component.
SparkEditor/Source/MaterialEditor/MaterialEditor.{h,cpp}	Standalone class with no production caller; the shipped panel is Panels/MaterialEditorPanel.
SparkEditor/Source/Lighting/LightingTools*.{h,cpp}	No production caller. BakeLightmaps wrote a fixed radial ramp in texture space (nothing scene-derived) and GenerateLightProbes discarded its probes -- no lightmap baking or light probes are claimed anywhere now.
SparkEditor/Source/Animation/* (timeline, clip manager, curve, playback)	No production caller.
SparkEditor/Source/AssetBrowser/AssetDatabase.{h,cpp}	No production caller.
Former AssetDatabase and PrefabManager test stubs	Decoy tests that included no production header; Tests/TestEditorSubsystemsReal.cpp covers the real PrefabManager.
GameModules/SparkGameFPS/Source/Game/{Console,Terrain,ArenaBuilder}.*	Unreachable in-game console overlay, unreferenced terrain, and an ArenaBuilder whose body was entirely commented out.
Shaders/Compiled/Basic{VS,PS}.cso, SparkEngine/Shaders/Compiled/Basic{VS,PS}.cso	Prebuilt bytecode is no longer shipped; the basic shaders are compiled from source (GraphicsDeviceResourcesWindowsShaders.cpp embeds them; Shaders/HLSL/BasicVS.hlsl / BasicPS.hlsl are the on-disk copies for the Linux/RHI path).

Editor panels in an honest Preview state

Panel	Status
DebugVisualizerPanel	Toggles are authored but no renderer consumes them and no debug-draw counts are reported; shows Preview - not connected.
ObjectPlacementPanel modes	Quick Place / Place Selected create real undoable entities; brush/line/grid/scatter, align, and snap settings are not read by the viewport.
DedicatedServerPanel discovery	Lists only the server launched from this editor; no discovery transport, no RCON, no kick/ban.

Graphics subsystems

The Graphics audit listed ~30 header-only files with no engine call sites (~10,000 lines total). Per-file verification found 1 filename-collision false positive among the high-value set and 2 already-wired among the smaller set; the remainder are legitimate reusable utilities and were documented in-header (resolution path "(c) document as intentional utility"). None were deleted — each is substantial working code (200–750 lines) useful when the corresponding render feature is built.

High-value utilities, all documented as intentional (selected):

File	Lines	Note
Graphics/BVHAccelerator.h	441	SAH-based hierarchical frustum/ray culling.
Graphics/VolumeSystem.h	461	Post-process volume blending. Tested via TestGraphicsIntegration.cpp.
Graphics/VoxelConeTracing.h	463	Voxel-cone-traced GI.
Graphics/GTAOEffect.h	444	Ground-truth AO post-process.
Graphics/SSAOTemporal.h	231	Temporal SSAO with history.
Graphics/MeshOptimizer.h	471	Vertex-cache / overdraw optimizer. Tested.
Graphics/RenderTargetPool.h	398	Pooled RT allocator.
Graphics/PipelineStateCache.h	398	Filename collision: this header defines D3D11PipelineStateCache, which the D3D11 path uses. Graphics/RHI/PipelineStateCache.h defines a different, not wired PipelineStateCache: GetOrCreate/Invalidate have no callers, and its lifecycle Initialize/Shutdown lines were removed in the 2026-09 sweep (see below).
Graphics/ReflectionProbeCache.h	317	Prefiltered env-map cache.
Graphics/CachedShadowAtlas.h	328	Per-light shadow atlas. Tested.
Graphics/RTHandleSystem.h	265	RT handle abstraction.
Graphics/ShaderVariantSystem.h	391	Keyword-based shader permutations. Tested.
Graphics/ShaderCrossCompiler.h	376	The DXBC target now compiles for real via d3dcompiler_47; DXIL/SPIR-V/GLSL/MSL are explicit not-integrated failures (exit 1), no longer success-with-empty-bytecode. CrossCompileHLSLtoGLSL survives only because Tests/TestGLSLPipelineIntegration.cpp asserts on it; CompileShader no longer calls it.
Graphics/ConstantBufferRing.h	362	Per-frame constant-buffer ring allocator.
Graphics/GPUDebugMarkers.h	377	Scoped PIX/RenderDoc/NSight markers.
Graphics/GPUTimestampQuery.h	490	GPU timestamp query pool.
Graphics/PersistentMaterialCB.h	220	Persistent constant buffer w/ dirty tracking.
Graphics/UICompositor.h	231	May be superseded by Engine/UI.
Graphics/DenoiserInterface.h	251	Abstract denoiser plugin interface.
Graphics/FastNoise2SIMD.h	749	SIMD procedural noise (FastNoise2 port).

Smaller utilities — 2 of 8 were false positives (already wired); the rest documented as intentional:

File	Lines	Note
Graphics/LineTrailRenderer.h	127	Data-carrier structs for line/trail components.
Graphics/SpringArm.h	69	Pure-CPU SpringArmState. Tests/TestSpringArm.cpp added (6 tests).
Graphics/DirtyRectTracker.h	167	CPU rectangle-merge for partial texture updates. Tested.
Graphics/ClusteredLightGPU.h	163	Bridge to structured-buffer arrays for forward+. Tested.
Graphics/ConstantBufferDiff.h	138	False positive. ConstantBufferDiffManager wired in the per-frame loop.
Graphics/RHI/DeferredDeletionQueue.h	121	Header-only with real test coverage (Tests/TestDeferredDeletionReal.cpp) but no production caller: D3D11Device has no such member and no backend calls Enqueue/ProcessQueue (D3D12Device has its own fence-based queue).
Graphics/RHI/RHIHandlePool.h	233	Generic HandlePool<T,N> template. Tested.
Graphics/RHI/TransientBufferAllocator.h	232	Per-frame bump allocator. Tested.

Tier 3 — Systems with tests but no engine/editor integration

Feature	File(s)	Current Status
ClusteredLightGPU	Graphics/ClusteredLightGPU.h	Tested; documented as an intentional Tier-2 utility (no render-path call yet).
DirtyRectTracker	Graphics/DirtyRectTracker.h	Tested; documented as intentional utility.
DeferredDeletionQueue	Graphics/RHI/DeferredDeletionQueue.h	Tested (TestDeferredDeletionReal.cpp); no production caller (see Tier 2).
AdvancedAssetPipeline	SparkEditor/Source/AssetPipeline/AdvancedAssetPipeline.h	3,835 lines with a real test (Tests/TestAdvancedAssetPipeline.cpp) and no production caller; ship-or-delete needs a product decision.

Resolved and no longer tracked: TutorialSystem, AssetAuditGraph, ConstantBufferDiff (wired), AIIntegratedSystem + ParallelPerceptionSystem.

Tier 4 — Editor infrastructure with unimplemented bodies

File	Current Status
SparkEditor/Source/Core/EditorWindowManager.h	Resolved (2026-09). SaveCurrentLayoutToFile()/LoadLayoutFromFile() now have real callers: EditorApplication::Initialize restores <EditorData>/window_layout.json and Shutdown writes it (EditorApplication::WindowLayoutFilePath).
SparkEditor/Source/Panels/SelectionManager.h	Partially resolved. Singleton now initialized/torn down from EditorUI. 13 new tests. Still pending: migrating HierarchyPanel/InspectorPanel/SceneView off their per-panel selection state — blocked on unifying SelectionManager::EntityId (uint32_t) with the editor's ObjectID (uint64_t).
SparkEditor/Source/Panels/NetworkDebugPanel.h	Resolved (data + UI). Data model and ImGui rendering implemented. Still pending: wiring NetworkManager to feed RecordBytesSent/RecordBytesRecv/LogPacket/SetCurrentLatency — verified 2026-06-08 that no producer calls these in the networking .cpp files yet.

Confirmed false positives (do NOT add to any deletion list)

System	Where verified
OnlineServiceManager	Wired (Initialize/Update/Shutdown) in GameplayLifecycleShared.cpp.
LootTableManager, CraftingSystem	Wired in GameplayLifecycleShared.cpp.
AnimNotifyManager	Wired in GameplayLifecycleShared.cpp.
CollaborativeEditSession	Real TCP + binary wire protocol in SparkEditor/Source/Communication/.
VideoPlayer	Wired (header-only by design).
CoroutineScheduler	Referenced from lifecycle + diagnostics (header-only by design).
WeatherSystem, TemporalEffects	Many .cpp call sites each (header-only by design).
InventorySystem.h, QuestSystem.h (FPS module)	Used in GameModules/SparkGameFPS/Source/Game/.

How to work through this in a follow-up session

1. One tier at a time — Tier 1 first (false promises), then Tier 4 (editor UX), then Tier 3 (tested-but-unwired), then Tier 2.
2. For each file, grep -r "ClassName" --include="*.cpp" --include="*.h" across the whole repo.
3. Choose exactly one per system: wire it in (Initialize/Update/Shutdown from GameplayLifecycleShared.cpp), delete it (file + tests + wiki), or document it as an intentional utility.
4. Avoid batch operations — each file needs its own decision.

Files to read first

• SparkEngine/Source/Core/Lifecycle/GameplayLifecycleShared.cpp — canonical wiring location.
• SparkEditor/Source/Core/EditorPanelFactory.cpp — where editor panels register.

Source & Freshness

• Original entry: .claude/knowledge/stub-and-abandoned-features-2026-04-10.md (compiled 2026-04-10; AI integration resolution 2026-04-14).
• Verified against codebase 2026-06-08; lifecycle-removal, deletion, and Preview-panel sections added from the 2026-09-05 release-readiness sweep (static verification against the working tree, no build/test evidence attached).

Status changes / verifications found during freshening:

• VRSystem — still a stub: confirmed Initialize() returns false with the OpenXR-not-linked warning.
• SteamTransport — still a stub: confirmed @warning block and false/-1 returns.
• FoliageSystem — confirmed RESOLVED and further advanced: FoliageRenderer, FoliageImpostorBaker (with Windows variants) exist and are wired in GameplayLifecycleShared.cpp (Initialize ~490, per-frame collect ~934, shutdown ~1174). The previously-deferred AssetPipeline binding is now done via InstallAssetPipelineLoader (~493).
• NetworkDebugPanel producer wiring — still pending: verified no RecordBytesSent/RecordBytesRecv/SetCurrentLatency calls exist in networking .cpp files.
• SelectionManager panel migration — still pending (EntityId/ObjectID width mismatch unresolved).
• Resolved items that no longer need tracking were removed from the tables in the 2026-09 sweep; the 2026-06 verification of the remaining rows stands.

Related Pages

• Gameplay & Engine Systems Status
• SparkGame Module Status
• Codebase Health
• Memory Integrity System