Luth Engine

July 13, 2026 · View on GitHub

Completed Epics

Summaries are intentionally terse — full writeups in history/, one file per epic slug.

Version	Epic	Summary	Date
v1.0.0	`job-system`	Fiber-based scheduler: FLS, Chase-Lev work-stealing, MPMC queues, SpinLock, isolated main thread	2026-03-07
v1.0.0	`frame-pipeline`	Triple-buffered pipelined execution (Game N / Render N-1 / GPU N-2), MAX_FRAMES_IN_FLIGHT=3	2026-03-07
v1.0.0	`render-graph`	DAG compile with dead-pass culling + batched barriers, serial outer with parallel inner recording	2026-03-07
v1.0.0	`cleanup`	Hot-path mutex → SpinLock, deleted GLAD/OpenGL remnants	2026-03-07
v1.0.0	`rendering-debug`	Fixed 5 rendering bugs: SceneColor disconnect, depth clear, bindless slot 0, Y-flip, front face winding	2026-03-15
v1.0.0	`pbr-material`	Cook-Torrance BRDF, Material SSBO (Set 2), per-RenderMode pipeline variants	2026-03-15
v1.0.0	`lighting-shadows`	LightUBO (Set 3), ShadowPass (2048² D32), PCF 3×3, ECS-driven light collection	2026-03-15
v1.0.0	`shader-system`	ShaderLibrary singleton, FileWatcher hot-reload, SPIRV-Cross reflection	2026-03-15
v1.0.0	`inspector-editor`	Save button + dirty tracking, Add Component dropdown, DirLight shadow controls, albedo color picker	2026-03-16
v1.0.0	`shader-asset-pipeline`	ShaderImporter, SPIR-V artifact cache, stable UUIDs via .meta, MaterialSystem dirty sync	2026-03-19
v1.0.0	`mipmap-generation`	vkCmdBlitImage chain, TextureSettings pipeline, sampler maxLod	2026-03-19
v1.0.0	`scene-serialization`	JSON `.luth` format, Win32 file dialogs, editor File menu + dirty tracking	2026-03-19
v1.0.0	`asset-lifetime-fix`	Scene holds shared_ptrs to prevent GC eviction, full async load chain, VMA shutdown fix	2026-03-21
v1.0.0	`frame-debugger`	GPUTimerPool, RenderGraphSnapshot, split-panel UI, event slider, named texture registry	2026-03-22
v1.0.0	`post-processing`	HDR (RGBA16F), bloom (extract + Gaussian blur), 4 tonemap operators, vignette, grain, CA	2026-03-22
v1.0.0	`pipeline-cache`	VkPipelineCache disk persistence, PipelineManager keyed by {shaderUUID, renderMode} with lazy creation	2026-03-22
v1.0.0	`skybox-ibl`	HDR equirect→cubemap, irradiance + pre-filtered env (5 mips) + BRDF LUT, split-sum ambient, Set 0 expanded to 4 bindings	2026-03-23
v1.0.0	`polish`	Bug fixes (transform/alpha/shadows), Rider theme, inspector overhaul, picking + outline, profiler rework	2026-03-25
v1.0.0	`editor-qa`	22-item QA pass: semantic EditorColors, HDR picker, outline children+occluded, recursive search, primitive geometry, project filters/sort	2026-03-30
v1.0.0	`animation-system`	Fiber-parallel sampling, GPU skinning (BoneMatrixBuffer SSBO), SQT blending, crossfade, layered override with masks, root motion	2026-03-30
v1.0.0	`smart-import-hot-reload`	Multi-strategy texture discovery, ImportReport/TextureRemapDialog, FileWatcher hot-reload, drop-to-current-dir	2026-03-31
v1.0.0	`frame-debugger-upgrade`	Trigger-based capture, per-draw scrubbing, DebuggerState machine, RenderCapturedFrame replay, depth linearization	2026-04-03
v1.1.0	`undo-redo`	Command pattern (14 types), UUID-based entity resolution, gizmo drag coalescing, compound commands, material snapshots	2026-04-09
v1.1.1	`architecture-cleanup`	RenderingSystem split (4060→2321 LOC): EditorCamera/CameraParams/IBL/FrameDebugger extracted; 9 passes moved to `renderer/passes/`	2026-04-13
v1.2.0	`compute-gpu-culling`	Compute pass + buffer support in render graph, GPU frustum cull shader, GPUObjectData SSBO, draws via vkCmdDrawIndexedIndirect	2026-04-15
v1.3.0	`csm`	4-cascade PSSM (bounding-sphere fit), 4-layer shadow array, per-cascade GPU cull, shader cascade selection + blend + bias	2026-04-16
v1.4.0	`frame-debugger-sync`	Archive sink + per-pass image staging, frozen-state auto-recapture, hierarchical EventNode tree, per-draw replay	2026-04-17
v1.5.0	`gtao`	DepthPrepass + half-res GTAO compute (prefilter → horizon integral → bilateral denoise), Jimenez 2016, Set 0 expanded to 6	2026-04-17
v1.6.0	`arch-cleanup`	Folder reorg: events/ extracted, utils/ dispersed, Components.h split, renderer/ subdivided into 7 concept folders	2026-04-18
v1.7.0	`arch-renderer-split`	RenderingSystem 3500→350 LOC: FrameTargets/DrawListBuilder/LightGatherer/CascadeBuilder extracted; RenderPipeline owns graph + resources	2026-04-18
v2.0.0	`arch-target-split`	Editor extracted from Luth.lib into Luthien.lib (~12k LOC); IEditorHooks breaks engine→editor include dep; Sandbox.exe descoped	2026-04-18
v2.1.0	`shader-asset-pipeline`	Single-stage shader assets (.vert/.frag/.comp = one artifact + UUID); ShaderHeader V2; all 24 engine shaders routed through pipeline	2026-04-18
v2.2.0	`math-abstraction`	`Luth::Math` facade — single `<glm/...>` owner. 25 wrappers + templated constants. 37 files migrated, 38 glm includes purged outside facade	2026-04-18
v2.3.0	`core-reorg`	`luth/core/` split into `types/` (LuthTypes/LuthMath/TypeTraits), `diagnostics/` (Log/LogFormatters/Profiler), `time/` (Time/Timer)	2026-04-18
v2.4.0	`animation-split`	`luth/animation/` dissolved: BoneMatrixBuffer/Skeleton/AnimationClip → `renderer/resources/`; AnimationController → `scene/components/`	2026-04-19
v2.5.0	`render-pipeline-split`	`RenderPipeline.cpp` 3104→781 LOC across 7 topic files + new `FrameDebuggerContext`. `CreatePipelines` split into 8 per-family builders	2026-04-19
v2.6.0	`rendering-system-slim`	`RenderingSystem` 533→395 LOC: LightingSystem + ShaderWatcher + PickingSystem extracted; cascades pass-by-value	2026-04-19
v2.7.0	`editor-cleanup`	Comment audit + Command.h reorg + CommandHistory deque + `Editor::GetPanel<T>` O(1) cache + `Editor::Init` decomposition	2026-04-19
v2.7.1	`editor-style-assets`	StylePreset → JSON assets (`luth/assets/styles/*.json`). EditorStyle 616→280 LOC. New `LoadStyle(nameOrPath)`, Save Current As...	2026-04-19
v2.7.2	`editor-widgets-reorg`	`luthien/UI.{h,cpp}` split into 5 widget files (Properties/AssetSlot/CollapsingHeader/InfoTable/TexturePreview) under `widgets/`	2026-04-19
v2.7.3	`editor-undo-gaps`	All 14 MarkDirty callsites wrapped in commands. New VectorElement/Insert/Erase + EntityActive commands. Drive-by `Entity::isActive` → Disabled tag	2026-04-23
v2.7.4	`editor-component-registry`	Hand-written `DrawComponent<T>` switch → type-erased `ComponentDrawerRegistry`. 8 drawers + DebugDrawers consolidated. InspectorPanel 976→255 LOC	2026-04-23
v2.7.5	`editor-scene-panel-slim`	`ScenePanel` 1001→443 LOC: ViewportRenderer + GizmoController + ViewportOverlays extracted to `viewport/`	2026-04-23
v2.8.0	`play-mode`	Editor state machine (Editing/Playing/Paused) + JSON scene snapshot; AnimationSystem gated; CommandHistory blocks during play; transport bar + viewport tint	2026-04-23
v2.8.1	`game-panel`	Dedicated Game panel rendering first Camera entity with letterbox; new `RenderView` + `ViewResources` cache; per-instance resize callback	2026-04-24
v2.8.2	`engine-consolidation`	Audit-driven housekeeping: roadmap restructure + 4 new arch docs (memory/profiling/validation-layers/version-glossary) + comment-banner sanitization + Tracy global memory hooks + CPU coverage gaps filled	2026-04-25
v2.8.3	`tracy-on-demand`	Hotfix: `TRACY_ON_DEMAND` so Tracy macros no-op when no profiler client connected. Fixes 10 MB/s launcher leak + 0.2 MB/s in-game leak (#30)	2026-04-25
v2.8.4	`pipeline-phase-3`	Pipelined CPU stages (Game N / Render N-1) on worker fibers; `RenderSnapshot` POD frozen at game-stage end; two-phase RG dispatch (1 yield/frame); 4 latent JobSystem bugs fixed along the way	2026-04-26
v2.8.5	`build-config-foundation`	`luth/core/BuildConfig.h` centralizes detection (`LUTH_BUILD_DEBUG/RELEASE/DIST` + derived flags); engine no longer tests `_DEBUG`/`NDEBUG`; first effort under tag-only release policy	2026-04-27
v2.8.6	`frame-debugger-polish`	Unity-style draw-scrub slider + tree-click snap; viewport pass overlay; depth archives via tonemapped preview; archive reuse + 10 Hz throttle eliminating editor freezes under continuous camera movement	2026-04-28
v2.8.7	`vulkan-correctness`	Tier-1 hardening: deletion-queue SpinLock (V1), RG WAW barriers, swapchain OUT_OF_DATE + deferred Present rebuild (V2), device Features2 validation, sync2 frame submit + RG-driven present transition	2026-04-28
v2.8.8	`animation-quick-pass`	`AnimationClip` becomes UUID-addressable asset (`.anim`); `Animation::ClipUUID` replaces integer indices; drawers swap Combo for `PropertyAsset`; foundation for `animation-controller-v2`	2026-04-28
v2.8.9	`persistent-buffer-ring`	Triple-buffered the 3 persistent CPU-mapped SSBOs (ObjectSSBO/IndirectBuffer/Material SSBO) so frame N writes never overlap frame N-1 GPU reads; VMA modernized off deprecated `CPU_TO_GPU`	2026-04-28
v2.8.10	`gpu-tagged-heap`	GPU half of Naughty Dog Onion/Garlic: `GPUTaggedPageAllocator` (2 MB pages from host-mapped backings, bulk-free wired to GPU N-2 timeline); Sets 2/4/5 rebind per-frame via UPDATE_AFTER_BIND	2026-04-29
v2.8.11	`slot-alloc-spinlock`	Closed v2.8.4 D6 carry-over: `MaterialSystem::m_Lock` + `BoneMatrixBuffer::m_Lock` → `Luth::SpinLock`; arch doc sweep	2026-04-29
v2.8.12	`shader-reload-async`	Drops per-save `vkDeviceWaitIdle` from shader hot-reload; defers old pipelines via `PushDeletion` (V1 SpinLock-safe), drained 3 frames later; shader save no longer drops a frame	2026-04-29
v2.8.13	`vulkan-polish`	Tier-2/3 cleanup before `jolt-physics`: validation messenger pNext-chained; `BindlessDescriptorSet` LIFO free-list; `RenderResourceCache` keyed on multimap; outline/grid push-constants routed through EditorSettings	2026-04-29
v2.8.14	`texture-async-uploads`	Texture half of `vulkan-polish` S4: `UploadImageMipped` records pre-barrier → staging copy → blit chain → `SHADER_READ_ONLY` in one cmd-buffer; 4-slot cmd-buffer ring; deferred-bindless-registration pump	2026-04-30
v2.9.0	`editor-foundation`	First AAA editor effort: Gather→Draw lifecycle for panels (parallel gather on worker fibers; main-thread ImGui draws from frozen snapshots); per-panel `LinearAllocator(64K)` gather scratch; 9 panels migrated	2026-05-01
v2.9.1	`editor-signal-bus`	Typed `EditorSignal` events on `EventBus` (selection/hierarchy/asset/project/play-state); panels react to subscriptions instead of polling; EventBus hardening (exception-safe dispatch, `SubscriptionHandle`, tracked alloc)	2026-05-02
v2.9.2	`editor-console-errors`	New `Log::AddSink` / `ILogSink` interface + `ConsolePanel` (sink + signal-based append, level filter, search, clipper); per-panel error boundary with stack-trace dump via Win32 DbgHelp	2026-05-02
v2.9.3	`editor-job-pump`	New `MainThreadPump` static facade — `Post(Callback)` any thread, `Drain()` on main; mirrors v2.9.1 EventBus shape (swap-and-drain, thread-assert, per-callback try/catch); foundation for autosave + thumbnails	2026-05-02
v2.9.4	`editor-autosave`	First `MainThreadPump` consumer: periodic side-channel autosave to `<project>/.luth/autosaves/` (never canonical); JSON snapshot on main + file write via IOThread; crash-recovery prompt in OpenScene	2026-05-03
v2.9.5	`editor-thumbnails`	ProjectPanel grid switches from FA-icons to rendered previews; `ThumbnailCache` (UUID-keyed, signal-driven invalidation), `ThumbnailGenerator` (worker-fiber CPU bake), `ThumbnailPreviewScene` (Lambert + ambient); disk-persisted	2026-05-03
v2.9.6	`editor-undo-fix`	Slider-driven inspector edits stop over-coalescing across release boundaries; new `EditState { changed, committed, itemId }` from every `UI::Property*`; per-T pre-edit value stash between `IsItemActivated`/`IsItemDeactivatedAfterEdit`	2026-05-04
v2.9.7	`editor-panels-polish`	ScenePanel toolbar re-laid (gizmo group + transport + render-mode + Debug/Camera/Gizmos splits); HierarchyPanel per-row visibility eye; ProjectPanel grid → BeginTable + clipper; new `EditorSettingsWindow`; `Window` menu + `Reset Layout`	2026-05-04
v2.9.8	`editor-inspector-polish`	`EditorClipboard` + `ComponentReset`/`ReplaceCommand` + per-component JSON Copy/Paste in all 8 drawers; new `InspectorHeader` + `Splitter` widgets; live orbit-cam 3D preview for Material/Model in pinned footer	2026-05-05
v2.9.9	`editor-workspaces`	AAA editor rework closeout: multi-named workspaces (`.ini` + `.workspace.json` sidecar); built-in `Default` ships at `luth/assets/workspaces/`; built-in shadows user copy of same name	2026-05-05
v2.9.10	`staging-ring-wrap-overlap`	Hotfix for two boundary-condition bugs in `UploadContext::AllocateStaging` producing intermittent banded pixel mixing under burst loads; explicit `wrapped` tracking + `head == tail` full-ring detection	2026-05-05
v2.9.11	`render-hardening`	Audit batch: per-frame UBOs migrate to `GPUTaggedPageAllocator`; `FreeTag(waitValue - 2)` correction (iter T+1 retires before its tag T pages free); Set 3 multi-view race fix; cross-view shadow sync	2026-05-06
v2.9.12	`render-pipeline-subsystems`	RenderPipeline god-class extracted into 6 per-domain subsystems (Global/Lighting/Geometry/GTAO/PostProcess/EditorOverlays), each owning lifecycle + descriptor sets + passes; friend coupling fully gone; RP shrinks to ~650 LOC orchestrator	2026-05-06
v2.9.15	`frame-debugger-polish-v2`	Batch-handles 3 deferred issues (#98 event-tree group ordering, #99 `Source = Game` replay, #100 Shadow/DepthPrepass/SelectionMask per-draw replay) + 8 drive-by polish; auto-recapture extends to IBL/skybox; cascade label shows splits range	2026-05-07
v2.10.0	`jolt-rigid-bodies`	Tier 0 of Jolt: vendor + `LuthJobSystemForJolt` adapter, `Collider`/`RigidBody`/`PhysicsBodyRuntime` components, kinematic/dynamic transform sync, debug-draw subsystem, CCD `motionQuality`; `WaitForCounter` UAF fix along the way	2026-05-14
v2.10.1	`jolt-physics-queries`	`Raycast` + `OverlapBox`/`Sphere`/`Capsule`; `LuthContactListener` (Godot-pattern trigger cache under SpinLock); 4-kind event surface + per-frame `DrainEvents`	2026-05-15
v2.10.2	`jolt-physics-assets`	`Physics::ShapeCache` (UUID + meshIndex + shapeKind keyed) for `ConvexHullShape` + `MeshShape` from Model data; `PhysicsMaterial` UUID-keyed asset; `ModelImportSettings::PhysicsBakeMode { None, Auto }` opt-in; hot-reload via AssetDatabase callback	2026-05-15
v2.10.3	`jolt-character-controller`	Tier 1 `JPH::CharacterVirtual` (requires paired `Collider Type::Capsule`); `ExtendedUpdate` defaults for stair/stick-to-floor; debug-draw colored by `GroundState`; stub `PlayerControllerSystem` until scripting lands	2026-05-18
v2.11.0	`custom-fibers`	Custom x86_64 MASM context switch + `VirtualAlloc` stacks replaces Win32 fibers so ASan can track per-fiber stack bounds. TIB ArbitraryUserPointer (`gs:[0x28]`) replaces Win32 FLS. ~5× faster switch (secondary win)	2026-05-19
v2.11.1	`foundation-testing`	28-case stress harness (V1–V6, AtomicCounter, LinearAllocator, TaggedPageAllocator, SpinLock, MPMCQueue, WorkStealingDeque) under DebugASan; caught two engine bugs inline	2026-05-20
v2.12.0	`async-compute-queue`	Three-queue Vulkan foundation (graphics + async-compute + transfer) with per-view 3-submit topology, RG queue routing + cross-queue barrier rule (TOP_OF_PIPE substitution on the reader's pre-barrier), CONCURRENT sharing opt-in per cross-queue resource, GTAO chain routed to async compute, UploadContext routed to dedicated transfer queue (DMA engine on discrete GPUs)	2026-05-20
v3.0.0	`bindless-migration`	rt-renderer arc opens. BDA enabled (mesh + tagged-heap buffers carry SHADER_DEVICE_ADDRESS_BIT, addresses cached); Set 1 binding 1 sampler array (4 canonical at 0-3, LIFO 4-31); `GPUMaterialData` 4→8 map indices + flag repack; `thumbnail_mesh` migrated to bindless (−120 LOC)	2026-05-22
v3.0.1	`slim-gbuffer`	`SlimGBufferPass` writes RG16F oct-normal + R8 roughness + RG16F NDC motion + R16U matID (depth-EQUAL, opaque-only). Adds `prevViewProjection` per-view (multi-view contamination fix), `prevModel` cache, dual-region `BoneMatrixBuffer` for prev-bones. Frame-debugger decoders + 4 `ShadeMode` toggles	2026-05-22
v3.0.2	`forward-plus`	Olsson 3D clustered lighting (16×9×24 grid) replaces 64-light UBO. `ClusterBuildPass` + `LightAssignPass` (async-compute) write per-cluster AABBs + atomic-packed light indices; PBR fragment loops cluster's lights (cap 128). Set 3 reshaped to 4 bindings, per-view. New `ShadeMode::ClustersDensity` 3D heat-map	2026-05-22
v3.0.3	`volumetric-fog`	Wronski frustum voxel fog (160×90×128 RGBA16F per view). Async-compute inject (cluster lights + CSM + `Component::FogVolume`) + integrate (front-to-back Beer-Lambert); graphics composite via standard alpha-blend. New `VolumetricSubsystem`, `VKTexture` 3D ctor, tagged-union `FogVolume` component + inspector + master toggle	2026-05-23
v3.0.4	`volumetric-validation`	Closes v3.0.3 known VUIDs. Image barriers set `VK_QUEUE_FAMILY_IGNORED` (was zero-init for CONCURRENT images); inject/composite declare per-cascade shadow + atlas reads so RG emits DSA → SHADER_READ_ONLY barriers; inject layout gains `UPDATE_AFTER_BIND` for per-frame rewrites. New 4th RG hazard documented	2026-05-23
v3.0.5	`volumetric-fog-polish` (initial)	Three deferred sub-tasks (Hillaire multi-scatter, temporal accumulation, ShadeMode viz) plus audit fixes. Temporal moved to dedicated `VolumetricResolve` compute pass after integrate (inject-time blend produced energy non-conservation). HG phase, point-light 1/d², sun-fog absorption, IBL irradiance multi-scatter, half-step transmittance, configurable Quality preset, shader `#include` support, k_ClusterSlicesZ 24→48	2026-05-24
v3.0.6	`volumetric-fog-polish` (follow-up)	Inject split into density + scatter passes joined by RG barrier (enables density-atlas sampling along sun ray — v3.0.5's single-pass `SunFogTransmittance` was dead-code). Canonical σ_t contract drops spurious `× density` in scatter (was double-applying). New `scatteringIntensity` knob, 3D Worley-FBM density noise, recalibrated defaults	2026-05-25
v3.0.7	`image-quality`	Closes Phase A. Tokuyoshi19 specular AA + AgX + AgX Punchy tonemaps. Karis14 TAA YCoCg-clip K3 — Halton(2,3) prefix-8 jitter, per-view RGBA16F history ping-pong, ~170 LOC resolve (closest-depth velocity, Blackman-Harris reconstruction, chroma narrow, luma feedback). Roberts R2 blue-noise volumetric dither; pbr.frag → `common/globals.glsl`	2026-05-25
v3.0.8	`rt-extensions`	Phase B opener: 4 KHR RT extensions enabled + feature validation + RT-mandatory device check; `VKRayTracingPipeline` + `RtShaderBindingTable` factories; validation-gated no-op `traceRays` smoke test	2026-05-26
v3.0.9	`blas-tlas`	Per-mesh BLAS at import (static + skinned, `skinning.comp` deformed-VB + `MODE_UPDATE` refit); per-frame TLAS rebuild on AsyncCompute with FNV-1a hash dirty-skip; Set 0 → 7 bindings (TLAS at b6)	2026-05-26
v3.0.10	`rt-shadows`	First RT-pipeline consumer: ray-traced sun shadows (1-spp, R8 mask) as default, raster CSM kept as `ShadowingMode` compare toggle; `RtSunShadowsPass` on AsyncCompute; `pbr.frag` CSM/RT dispatch. Closes Phase B	2026-05-31
v3.0.10	`gpu-debug-toolkit`	GPU crash-debugging subsystem: dynamic-load Nsight Aftermath, `LUTH_VALIDATION` runtime tiers (GPU-AV opt-in), per-pass NV checkpoints + device-lost dump; new `arch/gpu-crash-debugging.md`	2026-05-31
v3.0.11	`vulkan-sync-hardening`	Clean sync-val baseline before Phase C: GPU object names + RG pass labels, `LUTH_RG_DUMP`/`LUTH_RG_TRACE` + headless solver tests; loadOp-LOAD, swapchain-acquire, cross-queue-WAW barrier fixes	2026-06-06
v3.0.11	`gpu-device-lost`	Root-caused the recurring skinned `VK_ERROR_DEVICE_LOST`: 4 MiB `BoneMatrixBuffer` took the tagged-heap large-one-shot destroy path; ND-model fix recycles large tagged allocs (never `vkDestroyBuffer`)	2026-06-06
v3.0.12	`restir-di`	Bitterli 2020 ReSTIR DI for point lights: device-local (Garlic) reservoir buffers, rayQuery-in-compute initial RIS + temporal + spatial reuse, demodulated diffuse irradiance remodulated in `pbr.frag`, editor tuning; opens Phase C	2026-06-07
v3.0.13	`svgf-denoiser`	Schied 2017 SVGF over the demodulated ReSTIR DI: reproject (temporal EMA + moments) → variance (7×7 spatial fallback) → edge-aware à-trous, behind an `IDenoiser` abstraction; per-view image history + a GENERAL-preserving RG storage read; feedbackTap=−1, A-SVGF deferred	2026-06-07
v3.0.14	`restir-gi`	Ouyang 2021 ReSTIR GI: per-pixel 1-bounce path reservoirs + reconnection Jacobian (temporal/spatial reuse, RTXDI BASIC); real bindless secondary-hit material via a per-frame geometry table (`instanceCustomIndex` contract change + buffer_reference deref); second channel-parameterized SVGF instance denoises the bounce; editor tuning	2026-06-08
v3.0.15	`gi-polish`	Post-restir-gi follow-ups: TLAS builds for any RT consumer (DI/GI no longer dark under CSM), sun light added to the GI bounce, GI reservoir M·age debug view, and a zero-weight-reservoir fix (unlit hits keep a valid sample point — killed a world-plane confidence split + latent shadowed-region reuse bias)	2026-06-09
v3.0.16	`path-trace-reference`	Ground-truth path-traced reference mode: a rayQuery-in-compute megakernel reusing the TLAS + bindless materials, multi-bounce NEE + full Cook-Torrance BRDF + GGX VNDF lobe-MIS, fp32 progressive accumulation reset-on-change, `RenderMode` toggle + editor convergence UI; validates ReSTIR DI/GI convergence	2026-06-09
v3.0.17	`rt-reflections`	Stochastic RT specular reflections: GGX-VNDF rays from the slim G-buffer, NEE hit shading via the geometry table, demodulated split-sum composite in `pbr.frag` below a roughness cutoff; dedicated specular denoiser (SvgfDenoiser Reflections channel, hit-distance virtual reprojection); shared `common/brdf.glsl`. Supersedes SSR; opens Phase D	2026-06-09
v3.0.18	`volumetric-rt-shadows`	Per-froxel RT shadow rays in the fog inject-scatter pass: point lights + arbitrary occluders now cast fog shadows (sun swaps CSM→RT ray), 1-spp softened by the existing temporal resolve (no denoiser), default-off toggle; TLAS-build hoisted before the volumetric chain for registration-order correctness; folds two post-D.1 ReSTIR-DI audit fixes	2026-06-09
v3.1.0	`emissive-parity`	Opens the material-system arc: emissive factor + HDR strength, identical raster (`pbr.frag`) + RT (`geom_table.glsl`) emission closing the raster≠RT bug, editor controls + import bridge + inspector preview + `ShadeMode::Emission`; folds material-authoring fixes — metal/rough/color reach the GPU via direct fields, textureless emissive editable, no autosave reimport bounce	2026-06-09
v3.1.1	`material-eval-seam`	Retires `pbr.frag`'s hand-duplicated Cook-Torrance onto the shared `common/brdf.glsl` seam — raster==RT BRDF parity now structural (single source); neutral-renamed the `Pt*` functions; fp32-identical output	2026-06-10
v3.1.2	`cutout-rt`	Alpha-cutout materials hole correctly in every RT path: per-instance TLAS opaque flag (cutout→FORCE_NO_OPAQUE) + a shared `geom_table.glsl` candidate-loop alpha-test across PT/GI/reflections/ReSTIR-DI/volumetric fog; rewrites the lone RT-pipeline sun-shadow pass to rayQuery-compute, deleting the SBT/rgen/rmiss	2026-06-11
v3.1.3	`transparency-tier`	Transparent tier after the fog composite (fixes #32 skybox compositing): PPLL OIT default (per-view heads image + Garlic node pool, sort-K resolve) + per-view sorted A/B; corrected transparent shading — rayQuery sun shadow, cluster lights, fragment-depth froxel fog; TLAS cull masks make glass shadow-ray-invisible yet GI/reflection/PT-visible	2026-06-11
v3.1.4	`rt-normal-maps`	RT hits sample the normal map (TBN at the rayQuery hit, inverse-transpose normal matrix matching `pbr.vert`) + the occlusion map (`HitSurface.ao` → rt-reflections' IBL ambient; PT omits it — geometric occlusion); GI keeps its geometric secondary normal; dead alpha/specular/thickness indices marked reserved	2026-06-11
v3.1.5	`restir-di-specular`	ReSTIR DI gains specular: combined diffuse+spec RIS target (initial/temporal/spatial), demodulated F0-free specular from the shade pass, a dedicated 4th SVGF channel (surface-motion reproject), and pbr.frag F0-remodulation under `restirParams.z`; fixes metals/specular getting ~nothing from point lights	2026-06-11
v3.1.6	`model-import-fidelity`	Importer fidelity: faithful DCC node graph → entity tree (Model V4, un-baked static meshes), camera + light import, render-mode/cutout/cull/occlusion/UV1 from Assimp, engine-side `Scene::InstantiateModel`; fixes a node-rotation decompose-conjugate inversion; sRGB attempt reverted (editor not sRGB-aware)	2026-06-12
v3.2.0	`slang-spike`	Opens the `slang-material` series — Phase-0 gate GO: in-process `SlangCompiler` (Slang 2026.1) coexisting with libshaderc, one rayQuery+BDA+nonuniform-bindless shader ported, in-engine A/B bit-identical, link-spec valid across 2 stages; slang#10525/#9578 clear; default-off harness merged as the regression guard	2026-06-13
v3.2.1	`slang-toolchain`	`.slang` through the asset pipeline (stage via Slang reflection) + ShaderWatcher hot-reload, coexisting with GLSL; spike promoted to a SlangParityGuard whose gate is a deterministic SPIR-V NonUniform/caps scan, with the pixel A/B kept default-off as a diagnostic; multi-entry link probe retired	2026-06-13
v3.2.2	`slang-imaterial`	Bounded `material.slang` + one generic two-tier eval (RasterFetch/RayFetch) shared by all 9 raster/RT/transparent/volumetric consumers; production GLSL seam deleted; fixed a Slang global-session concurrency crash (fresh session per compile); drift-guard + spike retirement deferred	2026-06-14
v3.2.3	`slang-material-cleanup`	Closes the `slang-imaterial` follow-ups: an init-time `MaterialLayoutGuard` cross-checks `GPUMaterialData`/`GlobalUniforms` field offsets against their `.slang` twins via Slang reflection; full Phase-0 spike retirement — `SlangParityGuard` is now a gate-only SPIR-V scan on production `restir_gi_initial.slang`, deleting the pixel A/B + `geom_table.glsl`	2026-06-14
v3.2.4	`packed-texture-routing`	Import-side remap into the bounded channels: ORM aliasing, separate-map + spec-gloss derived-texture bake, DirectX-normal green-flip, TextureRole auto-detect + editor override; zero GPU-struct change, raster==RT by construction	2026-06-14
v3.2.5	`material-node-editor`	Blender-style channel-routing node graph → generated per-material Slang; raster per-material pipeline + RT variant-registry megakernel dispatch (raster==RT); 9-node vocab, live recompile, undo; effect-layers / transparent / constants-as-data deferred	2026-06-14
v3.2.6	`graph-param-buffer`	Graph constants routed to a per-material `gMatParams` buffer (binding 1 on the shared material set, both tiers) + structure-hash-keyed variants; value edits become data (no recompile), structurally-identical materials share one shader + variant, killing the recompile hitch + 16-cap + per-edit pipeline leak	2026-06-14
v3.2.7	`transparent-graph`	Node-graph materials decode through the shared variant registry in the raster transparent pass (sorted + OIT), closing the raster≠RT gap; one decode-seam swap + the two transparent shaders join the registry-reload set	2026-06-14
v3.2.8	`material-authoring`	M1-authoring closeout: graphed `mi.normal` honored raster==RT (tangent-space convention + `ApplyTangentNormal`), lightweight graph-aware material preview (self-contained `PreviewFetch` UBO + per-structure Lambert-over-graph consumer), searchable node quick-add; granular per-node undo deferred	2026-06-14
v3.3.0	`vertex-deformation`	GPU deformation seam (#161, D1–D4): one graphics-queue compute pass writes a per-asset deformed buffer that raster + the RT BLAS/geometry-table share (raster==RT structural); skinned→static-deformable generalization; procedural wind = global field (gusts/turbulence/world-space dir) + per-entity `Component::Wind`; empty-descriptor `deform.comp`, last-writer-wins per-asset	2026-06-19
v3.4.0	`profiling-observability`	Comprehensive Tracy coverage (~300 CPU zones to peer density, per-queue GPU zones graphics+async-compute, per-frame plots, event messages) + in-editor GPU pipeline statistics (per-pass overdraw) + render-graph barrier inspector; scheduler advisor deferred to #163 (touches V1–V6 hot paths, research-first)	2026-06-20
v3.5.0	`engine-optimization`	GPU perf pass on the RT chain: half-res ReSTIR DI/GI/Reflections (trace + denoise at half, shared bilateral upscale, default-off toggles; ~17% GI), DiSpec/GTAO/bloom skip when off, PathTrace gates the realtime pipeline at registration; tracker #164 stays open	2026-06-20
v3.6.0	`editor-panel-redesign`	Render panel 21 flat headers → 5 pipeline-stage tabs + search (drops Preferences dupes, unifies SVGF, surfaces hidden fields); Profiler rebuilt as a scheduler/memory/GPU dashboard (per-worker time-in-state occupancy, GPU-mem by resource type, EMA-stable per-pass table) on new JobSystem/VMA instrumentation; searchable Scene debug picker + 7 new ShadeModes; new FilterBox/CategoryPopup/Charts widgets (DiReservoir/Overdraw deferred)	2026-06-21
v3.6.1	`editor-qol`	Editor UX papercuts: New Folder auto-renames on create, Project panel refreshes on drag-drop import, single-mesh imports drop the redundant scene-root wrapper entity, Disabled cascades to whole subtrees in render, default window 1600×900 centered on the monitor	2026-06-28
v3.6.2	`render-correctness`	Three renderer fixes: persistent reservoir/OIT Garlic buffers destroyed (deferred N+2) on resize instead of recycle-orphaned in the device-local pool (fixes monotonic VRAM leak), grid + selection-mask overlays reconstruct an un-jittered projection (kills TAA shimmer), TLAS dirty-hash folds the full world matrix so static-mesh rotation/scale rebuilds the acceleration structure	2026-06-28
v3.6.3	`hierarchy-multiselect`	Multi-select consumers catch up to the selection vector: batch delete as one undo, Inspector apply-to-all (per-member + Reset/Remove/Add/Active via a MultiEdit broadcast context; combos primary-only), gizmo transforms the whole group about the active pivot, LMB-drag marquee select, Hierarchy shift-range select, viewport click-to-drill (root first then exact part), Delete from Hierarchy or viewport focus/hover, gizmo W/E/R on hover	2026-06-28
v3.6.4	`spotlights`	Third punctual light type on the point path: `SpotLight` component + 64-B `SpotLightData` appended to the Set 3 light SSBO, clustered via the shared tagged index list (sphere test, high-bit tag) with cone-attenuated `EvalClusteredLights`, unshadowed MVP; inspector drawer + hierarchy create/icon + scene/clipboard serialize + Assimp `aiLightSource_SPOT` import; cone gizmo + RT spot shadows deferred	2026-06-28
v3.6.5	`debug-draw-gizmos`	Editor in-world gizmos moved off ImGui onto the GPU debug-draw line pass: new `DebugDraw` wire-shape helpers (box/sphere/frustum/cone/arrow/cross), a game-stage `DebugGizmos` producer for lights/cameras/AABBs/bones gated by EditorViewportState toggles+palette, the deferred spot-light cone, FogVolume moved off its racy render-stage slot, ViewportOverlays thinned to click-select icons; depth-tested variant deferred	2026-06-28
v3.6.6	`bloom-pyramid`	Post bloom replaced with a Jimenez/CoD progressive compute pyramid: a Karis soft-knee prefilter + 5 13-tap downsamples + 5 tent upsamples accumulate additively up `ViewResources::bloomMip[6]` (per-view RGBA16F storage, RG-handle-threaded, in-place-RMW barrier) composited × strength; new radius/scatter knob, threshold/strength preserved, net VRAM win over the old 2-buffer 9-tap Gaussian	2026-06-29
v3.6.7	`log-channels`	Per-subsystem `LogCategory` channels (Core/Assets/Shaders/Renderer/Jobs/Physics/Scene/Editor, one spdlog logger each over shared sinks) threaded through every log site via `LH_LOG(cat,level)` (legacy `LH_CORE_*` kept as the Core alias); Console filters per-channel (all on, level filter hides Trace/Debug noise, errors bypass) with a per-row channel tag; stdout sink curated to INFO while `Luth.log`/editor keep full trace; reflection/per-asset/VMA spam demoted, Trace/Debug compiled out in Dist, `SetConsoleOutputCP` fixes em-dash mojibake	2026-06-29
v3.6.8	`phosphor-icons`	Editor icons rebuilt on Phosphor (Regular+Fill) behind a single semantic `Icons.h` remap + generated headers, dropping Font Awesome + the orphaned luth_icons font; Blender-style color-coded hierarchy entities (lights/camera/bone filled), filled transport/carets/render-mode states, sphere/circle render-mode glyphs, Scene/Material-Graph tab icons; new serialized `Component::Bone` marks skeleton joints	2026-06-29
v3.6.9	`gizmo-options`	Non-transform gizmos gain the physics Selected/All scope model (lights/cameras/bounds/bones/fog/wind) with shared unselected-alpha; new per-entity Wind direction arrow + scoped Fog; fog/wind viewport billboard icons (click-select, hierarchy-purple); all scene icons distance-scaled + clamped off the 64-px fill bake (crisp) with an Icon Size slider; per-category labels de-duplicated	2026-06-30
v3.7.0	`slang-shader-migration`	Completes the GLSL→Slang move: the remaining 58 non-material shaders ported (compute/raster/bindless/BDA), the dead RT-pipeline smoke path deleted, and libshaderc + the glslc toolchain removed — one shader language, one compiler, one reflection path	2026-06-30
v3.7.1	`shade-modes`	Debug shade-mode overhaul: data views (normals/IDs/channels) bypass bloom/tonemap via a passthrough sentinel, radiance views keep tonemap, raw GI/DI/reflection flag magenta when off, ShadowCascades/AO decoupled from global toggles, flat unlit wireframe + a new Shaded Wireframe overlay, transparent debug parity; folds no-fallback-sun (#33), back-face outline (#35), new-scene light+camera (#38).	2026-07-02
v3.7.3	`exposed-parameters`	Named graph parameters (name/group/ui on value nodes, codegen-blind) editable in the Inspector through the gMatParams data path; graph undo re-derives GPU state; variant cap 16→64 with beyond-cap stock in all tiers; coalesced registry reloads	2026-07-03
v3.7.3	`static-switches`	Compile-time StaticSwitch node: the canonical DFS emits only the selected branch (the other dead-strips from source + params), state flips are structure edits hash-cached both ways; named switches surface as Inspector checkboxes	2026-07-03
v3.7.3	`node-breadth`	16 new node types: math breadth, UV source + TextureSample UV pin, FBM Noise (graph_lib.slang, conditional import), fetch-context inputs (WorldPos/ViewDir/Time/Fresnel via ITexFetch getters filled per tier), sandboxed custom-Slang expression node; VertexColor deferred	2026-07-03
v3.7.3	`effect-layer`	Composable layers on the graph codegen: a MaterialInputs "layer" wire with MakeLayer/LayerBlend/Output.Surface (per-channel mask blend, normalized-lerp normal) + Triplanar (WorldNormal-weighted 3-plane) and DetailNormal (RNM) effect nodes from common/effects.slang; derivative-free raster==RT, typed pins, effect scalars as gMatParams data, hash-stable slot-6. Closes #157	2026-07-06
v3.7.4	`importer-hardening`	Model-import hardening: project-wide texture resolution + convention auto-bind, nested glTF texture copy, vertex format v6 (tangent handedness sign, vertex colors consumed into albedo raster==RT), opt-in material reimport-refresh, InstantiateModel multi-child-root crash guard	2026-07-10
v3.7.5	`async-blas-build`	Main-thread load/import freezes removed: ray-tracing BLAS builds deferred onto the async-compute TLAS pass (non-blocking poll, ready-gen folds late builds in, per-mesh gating); asset import made non-blocking end to end (per-UUID in-flight guard, atomic artifact writes, fire-and-forget ImportDirty, worker-thread drag-drop ingest, defer-until-loaded thumbnails). Closes #171	2026-07-10
v3.8.0	`rt-noise`	ReSTIR DI/GI noise + firefly reduction: RTXDI BASIC generalized-balance MIS (DI temporal+spatial, GI temporal) replacing biased 1/M, reuse final-visibility folded into post-spatial history, LDS group-outlier boiling filters, IGN-rotated Vogel reuse kernels, SVGF anti-firefly + roughness edge-stop + DI-spec demodulation + reservoir-confidence guides; jitter-consistent ReSTIR reconstruction removes the TAA-jitter flicker (de-jitter recon on all passes, a deliberate RTXDI deviation); TAA resolve hardening (NaN-safe history, Karis HDR-weighted blend, Catmull-Rom resample, sky reprojection). Closes #172	2026-07-11
v3.9.0	`texture-compression`	Import-time BCn block compression (~4x texture VRAM, fixes Sponza/Bistro OOM): bc7enc/rgbcx bake BC7 color/ORM + BC5 normals with a CPU mip chain, role-driven Auto policy + per-texture override (BC1/BC4/None), texture artifact V2 (MipLevels + version-reject, async LoadJob self-heal migration), transfer-queue pre-baked upload (no runtime blit), textureCompressionBC device gate, shader tangent-normal Z reconstruction. Closes #173	2026-07-11
v3.10.0	`emissive-area-lights`	Emissive-material triangles as sampled area lights: unified point+triangle local-light list + power-weighted alias table appended to the LightSSBO (no new binding/PC), (lightIndex, uv) DI reservoir re-instantiated per site (identity-shift, no Jacobian, area measure), MIS-free partition (DI owns emitter→primary, GI on-hit seed gated off via a geometry-table emitter bit + emitter NEE at the secondary hit, reflections keep on-hit + complementary DI-spec routing), render-side gatherer with instance-hash cache; PT-reference-validated. Closes #174	2026-07-11
v3.11.0	`surface-detail`	Two material-graph surface effects: parallax-occlusion (TangentViewDir + SampleLod fetch seam, repurposed-specular height slot, GraphParallax steep-march raster==RT) + UV-space decals (GPUMaterialData 80->96 decalIndex, GraphDecal inverse-affine box-masked placement, dual layer/value node); volume decals deferred to FUTURE. Closes #175	2026-07-12
v3.12.0	`shading-models`	Four production shading models on the shared `SurfaceBRDF`, raster==RT (analytic + PathTrace reference): clear-coat + anisotropy, dielectric transmission (exact IOR Fresnel + Walter GGX BTDF + Beer-Lambert, RT refraction closing the transparent-as-opaque gap), Estevez Charlie sheen, Burley/random-walk subsurface; `MaterialInputs`/`GPUMaterialData` 96->160 B, per-model graph pins + glTF import, screen-space DI/reflections keep the primary surface isotropic/sheen/SSS-free (Option A). Closes #176	2026-07-12
v3.13.0	`material-authoring-redesign`	Consolidation over the locked material surface (not a rewrite): terminology (IOR-driven dielectric F0 + `specular` weight, `thickness` split into glass + `subsurfaceThickness`, `scatterRadius`->`subsurfaceRadius`, glossary), HDRP-style inspector IA (Base group, packed Mask Map, feature-gated lobes), graph-declared Blackboard inputs (`MaterialGraph::properties` + `PropertyRef` -> `fetch.Param`, declared textures via a per-material `gMatTexParams` SSBO lifting the fixed-8-map ceiling, raster==RT==PT), + the deferred subsurfaceThickness graph pin. Closes #177	2026-07-13

Planned Epics

Effort scale (scope/difficulty, not calendar time): S = small, contained · M = some design decisions · L = significant refactor or new system · XL = full new subsystem.

Closed series — `rt-renderer` (Mode A, v3.0.0 → v3.0.18) ✅

CLOSED — milestone Release "RT Renderer" published; every effort is in the completed table above.

RT-first renderer modernization arc. Clustered Forward+ with bindless throughout, hardware ray tracing for shadows / GI / reflections, full Wronski volumetrics, ReSTIR + SVGF denoising, path-traced reference mode. Target showcase: Bhaal Temple, fully RT-lit. RT-mandatory (raises minimum HW to RT-capable GPU — counted toward the MAJOR bump).

Mode A — series start bumps Version.h to 3.0.0 (bindless-migration). Intermediate efforts PATCH-bump from there (v3.0.1 onwards), tag-only — no per-effort Release. Milestone Release at series end.

Umbrella issue: #127 (sub-effort issues created on demand; commits use Part of #127 trailer).

Phase A — Modern foundation

Effort	Issue	Size	Notes
A.1 `bindless-migration` ✅	#128	L	BDA enabled + Set 1 sampler array + `GPUMaterialData` 8 maps + `thumbnail_mesh` bindless — shipped v3.0.0
A.2 `slim-gbuffer` ✅	#129	M	Normal RG16F + roughness R8 + motion RG16F + matID R16U; prev-VP/model/bones plumbed — shipped v3.0.1
A.3 `forward-plus` ✅	#54	L	Clustered lighting + light assignment (existing #54 scope) — shipped v3.0.2
A.4 `volumetric-fog` ✅	#130	L	Wronski frustum voxel; light injection + integrate + composite — shipped v3.0.3 (+ `volumetric-fog-polish` v3.0.5/v3.0.6 #132 added temporal resolve, split inject + canonical math contract, scatter intensity knob, noise modulation)
A.5 `image-quality` ✅	#135	M	TAA Karis14 YCoCg-clip recipe + specular AA Tokuyoshi19 + AgX/AgX Punchy tonemaps + blue-noise volumetric dither — shipped v3.0.7. Closes Phase A.

Phase B — Hardware RT foundation ✅

Effort	Issue	Size	Notes
B.1 `rt-extensions` ✅	#137	M	4 KHR RT extensions + feature validation + RT pipeline/SBT factories + RT-mandatory device check — shipped v3.0.8
B.2 `blas-tlas` ✅	#138	L	Per-mesh BLAS (static + skinned) + per-frame TLAS rebuild on AsyncCompute + hash dirty-skip — shipped v3.0.9
B.3 `rt-shadows` ✅	#140	L	RT sun shadows default; raster CSM retained as `ShadowingMode` compare toggle (not retired — A/B precedent) — shipped v3.0.10. Closes Phase B.

Arc-adjacent efforts shipped alongside Phase B (tag-only): gpu-debug-toolkit (v3.0.10) — GPU crash-debugging subsystem; vulkan-sync-hardening + gpu-device-lost (v3.0.11) — clean sync-val baseline + the skinned device-lost root-cause, ahead of Phase C's barrier-heavy work.

Phase C — RT global illumination

Effort	Issue	Size	Notes
C.1 `restir-di` ✅	#146	XL	Bitterli 2020 — device-local reservoirs + rayQuery RIS + temporal/spatial reuse + demodulated DI — shipped v3.0.12
C.2 `svgf-denoiser` ✅	#147	XL	Schied 2017 SVGF + `IDenoiser` abstraction (NRD/RELAX swap reserved); feedbackTap=−1, A-SVGF + feedbackTap=1 deferred to a gated follow-up — shipped v3.0.13
C.3 `restir-gi` ✅	#127	XL	Ouyang 2021 — path reservoirs + reconnection Jacobian + real secondary material (geometry table) + 2nd SVGF instance — shipped v3.0.14

Phase C.5 — Path-traced reference mode

Effort	Issue	Size	Notes
C.5 `path-trace-reference` ✅	#148	M	rayQuery megakernel + multi-bounce NEE + full Cook-Torrance BRDF + GGX VNDF lobe-MIS + fp32 progressive accumulation; `RenderMode` toggle — shipped v3.0.16

Phase D — RT reflections + atmospheric polish

Effort	Issue	Size	Notes
D.1 `rt-reflections` ✅	#149	L	GGX-VNDF reflections from the slim G-buffer + specular denoiser (hit-distance virtual reprojection) + pbr split-sum composite — shipped v3.0.17
D.2 `volumetric-rt-shadows` ✅	#150	M	Per-froxel RT shadow rays in the inject-scatter pass — point-light + arbitrary-occluder fog shadows; sun swaps CSM→RT ray; 1-spp softened by the temporal resolve (no denoiser); default-off toggle — shipped v3.0.18

Out of arc (deferred to follow-up series)

character-shading — skin (Jimenez15) + hair (Karis16 + Marschner03) + cloth (Estevez17). Triggered by adding a character to Bhaal Temple
gpu-driven — mesh shaders + meshlet baker + HiZ occlusion (Framework 5 alignment)
virtual-geometry — Nanite-class virtualized geometry; long-tail

Active series — `material-system` (Mode A, v3.1.0)

Extends the uber-shader and factors a shared evaluate-at-surface-point seam that both pbr.frag and the RT hit (geom_table.glsl) call, retiring the hand-duplicated BRDF. Node-graph deferred to a later authoring layer over the seam. Mode A — series-open MINOR bump to 3.1.0 (emissive-parity); intermediate efforts PATCH-bump, tag-only; milestone Release at series end.

Umbrella issue: #151 (sub-effort issues created on demand; commits use Part of #151).

Effort	Issue	Size	Notes
M.1 `emissive-parity` ✅	#152	S–M	Emissive factor + HDR strength; raster==RT emission; editor/import/preview + `ShadeMode::Emission` — shipped v3.1.0
M.2 `material-eval-seam` ✅	—	S	`pbr.frag` migrated onto the existing `common/brdf.glsl` seam (`rt-reflections` built it); `Pt*` renamed; raster==RT BRDF parity structural — shipped v3.1.1
M.3 `cutout-rt` ✅	—	M	Per-instance TLAS opaque flag + shared candidate-loop alpha-test (rayQuery-centric, not anyhit BLAS); cutout correct in RT shadows / GI / reflections / DI / fog; lone RT-pipeline sun-shadow pass rewritten to rayQuery-compute — shipped v3.1.2
M.4 `transparency-tier` ✅	#32	M→L	Dedicated pass after the fog composite: PPLL OIT default + per-view sorted A/B, rayQuery sun shadow + fragment-depth fog, cull-masked RT visibility (shadow-ray-excluded, GI/reflection-visible; scope override: true OIT from the start, superseding "WBOIT only if layered") — shipped v3.1.3
M.5 `rt-normal-maps` ✅	#153	S	RT-hit normal-map TBN + occlusion parity (inverse-transpose normal matrix); applied in PT + rt-reflections, GI keeps its geometric secondary normal; folds the dead-index audit comment — shipped v3.1.4
M.6 `restir-di-specular` ✅	#154	M→L	ReSTIR DI specular: combined diffuse+spec RIS target + demodulated F0-free shade output + dedicated 4th SVGF channel (surface-motion reproject) + pbr.frag F0-remod (not envBRDF — point-spec lobe applied at shade); research-backed (NRD/RTXDI/Bevy Solari) — shipped v3.1.5

The Slang IMaterial spike → GO (v3.2.0), opening the slang-material series below — the deferred node-graph authoring lands there.

gpu-particles (#57, L) — compute sim, showcase-sized (fire / ember / smoke / motes in god ray). Parallelizable — not a material-system dependency; drop into any renderer slot.

Active series — `slang-material` (Mode A, v3.2.0)

GLSL→Slang migration + a bounded IMaterial surface (link-time specialization) shared across raster / RT / path-trace, plus a node-graph authoring layer emitting into that surface — continues material-system's deferred node-graph. Mode A — series-open MINOR bump to 3.2.0 (the slang-spike gate); intermediate efforts PATCH-bump, tag-only; milestone Release at series end. Detailed design: local docs/development/epics/slang-material.md.

Umbrella issue: #157 (sub-effort issues on demand; commits use Part of #157).

Phase	Effort	Size	Notes
0 ✅	`slang-spike`	M	Phase-0 gate GO — in-process compiler + rayQuery/BDA/bindless A/B + link-spec, all green — shipped v3.2.0
1 ✅	`slang-toolchain`	M	`.slang` asset-pipeline dispatch (stage via reflection) + ShaderWatcher hot-reload + SlangParityGuard (deterministic SPIR-V NonUniform/caps gate; pixel A/B = diagnostic) — shipped v3.2.1
2 ✅	`slang-imaterial`	L	bounded `material.slang` + two-tier generic eval shared by all 9 consumers; production seam deleted — shipped v3.2.2; hardening follow-ups (layout drift-guard + spike/geom_table retirement) shipped v3.2.3
3 ✅	packed-texture routing	L	Import-side remap into the bounded channels: ORM aliasing, separate-map + spec-gloss derived-texture bake, DirectX-normal green-flip, TextureRole auto-detect + editor override; zero GPU-struct change, raster==RT by construction; shipped v3.2.4
4	composable effect layer	L	Link-specialized stackable effects; the node editor emits into it (no longer blocks 5)
5 ✅	node editor → bounded surface	XL	Channel-routing node graph → generated per-material Slang; raster per-material pipeline + RT variant-registry dispatch (raster==RT); done before Phase 4 — shipped v3.2.5

✅ graph-param-buffer (v3.2.6) — constants→per-material-data + structure-hash-keyed variants (recompile-on-edit, the RT-recompile hitch, the 16-variant cap, and the per-edit pipeline leak all gone).

Materials arc (M1–M5)

Agreed forward order (2026-06-14) — dependency-clean, params as the keystone: a tunable in an effect unit (M3) or shading model (M4) must be a parameter, not a baked constant, or it reintroduces the anti-pattern graph-param-buffer just removed, so M2 precedes M3/M4. M1–M3 close slang-material (#157); M4–M5 open follow-on series. gpu-particles (#57) stays parallelizable throughout. One effort per conversation, plan-mode each.

Completion plan (2026-07-11): finish the whole remaining arc across conversations, in 3 shippable sub-arcs (Mode A, one branch + one MINOR each):

surface-detail (v3.11.0) ✅: parallax-occlusion first (adds the TangentViewDir fetch getter, foundation), then decals (UV-space; blood/grime, Bhaal-thematic).
shading-models (v3.12.0) ✅: clear-coat+anisotropy, then dielectric-transmission (RT refraction, closes the transparent-as-opaque gap), sheen-cloth, subsurface-skin; each extends MaterialInputs + brdf.slang, raster==RT.
material-authoring-redesign (v3.13.0) ✅: consolidation over the locked surface (not a rewrite) — terminology (dielectric F0 via IOR + specular, thickness split into glass + subsurfaceThickness, scatterRadius→subsurfaceRadius, glossary) → HDRP-style inspector IA (Base group, packed Mask Map, feature-gated lobes) → graph-declared (Blackboard) inputs (MaterialGraph::properties + PropertyRef, declared textures via gMatTexParams lifting the fixed-8-map ceiling, raster==RT==PT). Closes #177; virtual-texturing (v3.14.0) is next.
virtual-texturing (v3.14.0): separable XL capstone; may spin out as its own series.
hair deferred out of arc to the character vertical (asset-gated on hair geometry/cards).
Fable5 drives the BRDF/BTDF derivation + raster==RT seam on each shading-model effort; normal model for surface-detail plumbing (Fable5 verify pass on POM's raymarch).

Arc	Effort	Size	Notes
M1 authoring	`transparent-graph` ✅	M	Transparent/OIT raster decode routed through the variant registry (raster==RT), same path the RT hit uses — shipped v3.2.7.
M1 authoring	`graph-normal-preview` ✅	S–M	Graphed `mi.normal` honored raster==RT (tangent convention + `ApplyTangentNormal`) + lightweight graph-aware preview (Lambert-over-graph, self-contained UBO) — shipped v3.2.8.
M1 authoring	`node-breadth` ✅	M	9 math nodes + UV source/pin + FBM Noise + WorldPos/ViewDir/Time/Fresnel context inputs + sandboxed custom-Slang node; VertexColor deferred (vertex-format effort), enum switch + UVTransform composable/deferred — shipped v3.7.3.
M1 authoring	`node-ux`	S	Search / quick-add ✅ (v3.2.8); comments/frames + group-to-subgraph shelved (vendored GraphEditor widget lacks support — needs a widget effort); granular per-node undo deferred.
M2 params ⭐	`exposed-parameters` ✅	M	Named/grouped params on value nodes (float/color/remap/tex-slot + bool hint), inspector-editable through the gMatParams data path; folds variant-cap parity + coalesced-reload hardening — shipped v3.7.3.
M2 params ⭐	`static-switches` ✅	M	Compile-time StaticSwitch node (Off/On emission-time selection folded into the structure hash); named switches = Inspector checkboxes; enum/N-way deferred until a use case names its options — shipped v3.7.3.
M3 composition	`effect-layer` ✅	L	Composable layer substrate on the graph codegen (MaterialInputs bundle wire + MakeLayer/LayerBlend/Output.Surface); Triplanar + DetailNormal demonstrate it, raster==RT by construction. Shipped v3.7.3, closes #157.
M3 composition	`triplanar` ✅ / `detail-maps` ✅ / `parallax-occlusion` ✅ / `decals` ✅	M–L	Triplanar + DetailNormal shipped with `effect-layer` (v3.7.3); POM + UV-space decals shipped on `feat/surface-detail` (#175: seam getters, height + decal slots, GraphParallax + GraphDecal raster==RT, layer-node decal); surface-detail sub-arc ready to close at v3.11.0.
M4 shading	`clear-coat` + `anisotropy` ✅	M	Lacquer / brushed metal; `MaterialInputs` 96->112 B + aniso GGX + coat lobe on a shared `SurfaceBRDF`, raster==RT (analytic + PathTrace reference); screen-space DI/reflections keep the primary surface isotropic (documented deviation). Shipped on `feat/shading-models`.
M4 shading	`dielectric-transmission` ✅	L	Glass: IOR + exact dielectric Fresnel + Walter GGX BTDF + Beer-Lambert, `MaterialInputs`/`GPUMaterialData` 112->128 B; PT refracts (4th glass lobe + medium tracking, RNG bit-identical at transmission 0), realtime raster gets screen-space refraction (per-view backdrop copy + roughness blur), transmission tint from attenuationColor not albedo (raster==RT); opacity was C++-side FORCE_OPAQUE (the `gl_RayFlagsOpaqueEXT` note was stale), colored shadows + refracted NEE deferred. Shipped on `feat/shading-models`.
M4 shading	`sheen-cloth` ✅	M	Estevez17: Charlie NDF + paper soft-V + analytic energy comp; `MaterialInputs`/`GPUMaterialData` 128->144 B, sheen lobe under the coat on the shared `SurfaceBRDF`, raster==RT (analytic + IBL env + PathTrace, no new PT RNG draw); graph pins + glTF import; DI/reflections keep the primary surface sheen-free (Option A). Shipped on `feat/shading-models`.
M4 shading	`subsurface-skin` ✅	L	Jimenez15/Burley skin/wax/marble: a local diffusion-profile diffuse (Burley wrap + Frostbite thickness translucency) on the shared `SurfaceBRDF`, `MaterialInputs`/`GPUMaterialData` 144->160 B; PT random-walk oracle (Chiang albedo->sigma, collision walk reusing the glass medium), raster==RT, RNG-stream bit-identical at subsurfaceColor 0; subsurface + thickness texture maps + graph pins. Closes the shading-models sub-arc (v3.12.0). Shipped on `feat/shading-models`.
M4 shading	`hair`	L	Marschner03 / Karis16 — needs hair geometry/cards (= the deferred `character-shading`).
M5 texturing	`virtual-texturing` + sRGB-authoring revisit	XL	Streaming-scale texturing; revisit the v3.1.6 sRGB-authoring revert. Long-tail.

Gameplay enablement

Pri	Epic	Issue	Target	Effort	Deps
4	`scripting` (C# or Lua)	NEW	v3.2.0	XL	`rt-renderer` ✅
5	`prefab-system`	NEW	v3.2.x	M	`scripting`

Scripting unblocks the PlayerControllerSystem stub deletion and is the prerequisite for most gameplay-side future ideas.

Animation maturity

Pri	Epic	Issue	Target	Effort	Deps
6	`animation-controller-v2`	#94	v3.2.0	XL	`animation-quick-pass` ✅

Polish (no fixed slot — opportunistic)

Epic	Issue	Effort	Notes
`procedural-sky`	NEW	M	Independent; drop into any quiet renderer slot
`jiggle-bones`	#61	M	Benefits from `jolt-physics` ✅ colliders
`rg-aliasing` (optional)	NEW	M	Defer unless `rt-renderer` Phase A/D pressures transient VRAM

fxaa-taa (#72) — TAA absorbed into rt-renderer Phase A.5; FXAA dropped (TAA is strictly better given motion vectors land in Phase A.2).

Detailed design lives in docs/development/epics/<slug>.md (local, never committed) once an epic enters plan-mode. The arch docs (arch/) are the canonical reference for system invariants.

Versioning

Semantic Versioning (MAJOR.MINOR.PATCH):

MAJOR — fundamental architecture changes or engine rewrites
MINOR — each completed epic with user-visible changes
PATCH — bug fixes and polish between epics

Version is centralized in luth/source/luth/core/Version.h.

Future Ideas

Long-tail wishlist of unscheduled work lives in FUTURE.md. Categories: physics maturity, gameplay enablement, rendering (beyond planned-epic deps), animation maturity, audio, editor & tools, profiling / memory.