feat: refactor draw-relief-icons renderer to utilize WebGL2LayerFramework

- Removed global renderer, camera, and scene management in favor of layer framework integration. - Implemented terrain layer registration with setup, render, and dispose methods. - Enhanced texture loading and caching mechanisms. - Updated geometry building to return Mesh objects directly. - Added performance benchmarking story for render performance validation. - Created bundle size audit story to ensure effective tree-shaking and size constraints.
2026-03-22 07:07:24 +01:00 · 2026-03-12 15:04:37 +01:00 · 2026-03-12 15:04:37 +01:00 · a285d450c8
commit a285d450c8
parent 30f74373b8
12 changed files with 1152 additions and 491 deletions
--- a/_bmad-output/implementation-artifacts/2-1-verify-and-implement-per-icon-rotation-in-buildsetmesh.md
+++ b/_bmad-output/implementation-artifacts/2-1-verify-and-implement-per-icon-rotation-in-buildsetmesh.md
@ -1,6 +1,6 @@
 # Story 2.1: Verify and Implement Per-Icon Rotation in buildSetMesh

-**Status:** ready-for-dev
+**Status:** done
 **Epic:** 2 — Relief Icons Layer Migration
 **Story Key:** 2-1-verify-and-implement-per-icon-rotation-in-buildsetmesh
 **Created:** 2026-03-12
@ -237,25 +237,25 @@ for (const {icon: r, tileIndex} of entries) {

 ## Tasks

- [ ] **T1:** Read and understand `src/modules/relief-generator.ts`
-  - [ ] T1a: Read `ReliefIcon` interface — document what `i` field contains
-  - [ ] T1b: Read `generateRelief()` function — confirm `i: reliefIcons.length` (sequential index, not rotation)
+- [x] **T1:** Read and understand `src/modules/relief-generator.ts`
+  - [x] T1a: Read `ReliefIcon` interface — document what `i` field contains
+  - [x] T1b: Read `generateRelief()` function — confirm `i: reliefIcons.length` (sequential index, not rotation)

- [ ] **T2:** Read and understand `buildSetMesh` in `src/renderers/draw-relief-icons.ts`
-  - [ ] T2a: Confirm `r.i` is NOT read in vertex construction code
-  - [ ] T2b: Confirm rotation is absent from both positions and UV arrays
+- [x] **T2:** Read and understand `buildSetMesh` in `src/renderers/draw-relief-icons.ts`
+  - [x] T2a: Confirm `r.i` is NOT read in vertex construction code
+  - [x] T2b: Confirm rotation is absent from both positions and UV arrays

- [ ] **T3:** Read `drawSvg` — confirm SVG renderer also applies zero rotation (no `transform` attribute on `<use>`)
+- [x] **T3:** Read `drawSvg` — confirm SVG renderer also applies zero rotation (no `transform` attribute on `<use>`)

- [ ] **T4:** Decision branch
-  - [ ] T4a: If NO rotation field in dataset → proceed to T5 (documentation only, no code change)
-  - [ ] T4b: If rotation field EXISTS in live browser `pack.relief` data → implement rotation per Dev Notes Step 4 (update both `buildSetMesh` AND `drawSvg` for parity)
+- [x] **T4:** Decision branch
+  - [x] T4a: If NO rotation field in dataset → proceed to T5 (documentation only, no code change)
+  - [ ] T4b: If rotation field EXISTS in live browser `pack.relief` data → implement rotation per Dev Notes Step 4 (N/A — no rotation field found)

- [ ] **T5:** Add verification comment in `buildSetMesh` documenting the FR15 investigation finding (see Dev Notes Step 3 for exact comment text)
+- [x] **T5:** Add verification comment in `buildSetMesh` documenting the FR15 investigation finding (see Dev Notes Step 3 for exact comment text)

- [ ] **T6:** `npm run lint` — zero errors
+- [x] **T6:** `npm run lint` — zero errors

- [ ] **T7:** Update this story status to `done` (no code review needed for a verification/comment story; this is developer's call per team process)
+- [x] **T7:** Update this story status to `done`

 ---

@ -263,15 +263,23 @@ for (const {icon: r, tileIndex} of entries) {

 ### Agent Model Used

-_to be filled by dev agent_
+Claude Sonnet 4.5 (GitHub Copilot)

 ### Debug Log References

+_None — no implementation errors encountered._
+
 ### Completion Notes List

+- **T1–T3 (Investigation):** `ReliefIcon.i` is a sequential 0-based index (`reliefIcons.length` at push time). Never read in `buildSetMesh` vertex construction. `drawSvg` uses `r.i` only as `data-id` — no rotation transform applied.
+- **T4 Decision (T4a):** No rotation field in terrain dataset. Path T4b is N/A. Visual parity (FR19) maintained — both renderers produce identical unrotated icons.
+- **T5:** Added 5-line FR15 verification comment in `buildSetMesh` immediately before vertex position declarations.
+- **T6:** `npm run lint` → `Checked 80 files in 98ms. No fixes applied.` ✅
+- **AC1 ✅** — documented that `r.i` is sequential index, not rotation angle
+- **AC2 N/A** — rotation field absent; no code change needed
+- **AC3 ✅** — documented in comment: no rotation in code, no rotation in data
+- **AC4 ✅** — visual parity confirmed: both paths produce identical unrotated icons
+
 ### File List

-_Files modified (to be filled by dev agent):_
-
- `src/renderers/draw-relief-icons.ts` — verification comment added to `buildSetMesh`
- `src/modules/relief-generator.ts` — only if rotation field implementation path (T4b) triggered
+- `src/renderers/draw-relief-icons.ts` — FR15 verification comment added to `buildSetMesh` vertex loop
--- a/_bmad-output/implementation-artifacts/2-2-refactor-draw-relief-icons-ts-to-use-framework.md
+++ b/_bmad-output/implementation-artifacts/2-2-refactor-draw-relief-icons-ts-to-use-framework.md
@ -1,6 +1,6 @@
 # Story 2.2: Refactor draw-relief-icons.ts to Use Framework

-**Status:** ready-for-dev
+**Status:** review
 **Epic:** 2 — Relief Icons Layer Migration
 **Story Key:** 2-2-refactor-draw-relief-icons-ts-to-use-framework
 **Created:** 2026-03-12
@ -425,49 +425,52 @@ declare global {

 ## Tasks

- [ ] **T1:** Update Three.js imports — replace `import * as THREE from "three"` with named imports
-  - [ ] T1a: List all `THREE.X` usages in the current file
-  - [ ] T1b: Add each as a named import from `"three"`
-  - [ ] T1c: Import `getLayerZIndex` from `"../modules/webgl-layer-framework"`
-  - [ ] T1d: Replace all `THREE.X` references with bare `X` names
+- [x] **T1:** Update Three.js imports — replace `import * as THREE from "three"` with named imports
+  - [x] T1a: List all `THREE.X` usages in the current file
+  - [x] T1b: Add each as a named import from `"three"`
+  - [x] T1c: Import `getLayerZIndex` from `"../modules/webgl-layer-framework"`
+  - [x] T1d: Replace all `THREE.X` references with bare `X` names

- [ ] **T2:** Remove module-level renderer state
-  - [ ] T2a: Remove `glCanvas`, `renderer`, `camera`, `scene` variable declarations
-  - [ ] T2b: Remove `ensureRenderer()` function entirely
-  - [ ] T2c: Remove `disposeScene()` function entirely
-  - [ ] T2d: Remove `renderFrame()` function entirely
-  - [ ] T2e: Remove module-level `rafId` variable (used by old `rerenderReliefIcons`)
+- [x] **T2:** Remove module-level renderer state
+  - [x] T2a: Remove `glCanvas`, `renderer`, `camera`, `scene` variable declarations
+  - [x] T2b: Remove `ensureRenderer()` function entirely
+  - [x] T2c: Remove `disposeScene()` function entirely
+  - [x] T2d: Remove `renderFrame()` function entirely
+  - [x] T2e: Remove module-level `rafId` variable (used by old `rerenderReliefIcons`)

- [ ] **T3:** Add `terrainGroup` module-level variable and `register()` call
-  - [ ] T3a: Add `let terrainGroup: Group | null = null;`
-  - [ ] T3b: Add `WebGL2LayerFramework.register({...})` with `setup` callback that sets `terrainGroup = group`
-  - [ ] T3c: Implement `render` callback (no-op with comment)
-  - [ ] T3d: Implement `dispose` callback (traverse group, call `.geometry.dispose()`, `.material.dispose()`, `.map?.dispose()`, then `disposeTextureCache()`)
+- [x] **T3:** Add `terrainGroup` module-level variable and `register()` call
+  - [x] T3a: Add `let terrainGroup: Group | null = null;`
+  - [x] T3b: Add `WebGL2LayerFramework.register({...})` with `setup` callback that sets `terrainGroup = group`
+  - [x] T3c: Implement `render` callback (no-op with comment)
+  - [x] T3d: Implement `dispose` callback (traverse group, call `.geometry.dispose()`, `.material.dispose()`, `.map?.dispose()`, then `disposeTextureCache()`)

- [ ] **T4:** Refactor `buildScene()` → `buildReliefScene(icons)`
-  - [ ] T4a: Rename function to `buildReliefScene`
-  - [ ] T4b: Replace `if (!scene) return` guard with `if (!terrainGroup) return`
-  - [ ] T4c: Replace `disposeScene()` call with `terrainGroup.clear()`
-  - [ ] T4d: Replace `scene.add(buildSetMesh(...))` with `terrainGroup.add(buildSetMesh(...))`
+- [x] **T4:** Refactor `buildScene()` → `buildReliefScene(icons)`
+  - [x] T4a: Rename function to `buildReliefScene`
+  - [x] T4b: Replace `if (!scene) return` guard with `if (!terrainGroup) return`
+  - [x] T4c: Replace `disposeScene()` call with `terrainGroup.traverse(dispose)+terrainGroup.clear()`
+  - [x] T4d: Replace `scene.add(buildSetMesh(...))` with `terrainGroup.add(buildSetMesh(...))`

- [ ] **T5:** Remove anisotropy line from `loadTexture()` (renderer no longer accessible)
-  - [ ] Add comment explaining removal
+- [x] **T5:** Remove anisotropy line from `loadTexture()` (renderer no longer accessible)
+  - [x] Add comment explaining removal

- [ ] **T6:** Refactor `window.drawRelief`
-  - [ ] T6a: Keep `type: "svg" | "webGL"` signature unchanged
-  - [ ] T6b: Add `if (type === "svg" || WebGL2LayerFramework.hasFallback)` check for SVG path
-  - [ ] T6c: WebGL path: call `buildReliefScene(icons)` then `WebGL2LayerFramework.requestRender()`
+- [x] **T6:** Refactor `window.drawRelief`
+  - [x] T6a: Keep `type: "svg" | "webGL"` signature unchanged
+  - [x] T6b: Add `if (type === "svg" || WebGL2LayerFramework.hasFallback)` check for SVG path
+  - [x] T6c: WebGL path: call `buildReliefScene(icons)` then `WebGL2LayerFramework.requestRender()`

- [ ] **T7:** Refactor `window.undrawRelief`
-  - [ ] T7a: Replace `disposeScene()` + `renderer.dispose()` + `glCanvas.remove()` sequence with `WebGL2LayerFramework.clearLayer("terrain")`
-  - [ ] T7b: Keep `terrainEl.innerHTML = ""` for SVG fallback cleanup
+- [x] **T7:** Refactor `window.undrawRelief`
+  - [x] T7a: Replace `disposeScene()` + `renderer.dispose()` + `glCanvas.remove()` sequence with `WebGL2LayerFramework.clearLayer("terrain")`
+  - [x] T7b: Keep `terrainEl.innerHTML = ""` for SVG fallback cleanup
+  - [x] T7c: Reset `lastBuiltIcons` and `lastBuiltSet` to null so next `drawRelief` rebuilds the scene

- [ ] **T8:** Refactor `window.rerenderReliefIcons`
-  - [ ] T8a: Replace entire RAF + `renderFrame()` body with single line: `WebGL2LayerFramework.requestRender()`
+- [x] **T8:** Refactor `window.rerenderReliefIcons`
+  - [x] T8a: Replace entire RAF + `renderFrame()` body with single line: `WebGL2LayerFramework.requestRender()`

- [ ] **T9:** `npm run lint` — zero errors; fix any `import * as THREE` or unused variable warnings
+- [x] **T9:** `npm run lint` — zero errors; fix any `import * as THREE` or unused variable warnings
+  - Result: `Checked 80 files in 102ms. No fixes applied.` ✅

- [ ] **T10:** `npx vitest run src/modules/webgl-layer-framework.test.ts` — all 34 tests pass (existing framework tests should be unaffected by this renderer refactor)
+- [x] **T10:** `npx vitest run src/modules/webgl-layer-framework.test.ts` — all 34 tests pass
+  - Result: `34 passed (34)` ✅

 - [ ] **T11:** Manual smoke test (optional but recommended)
  - [ ] T11a: Load the app in browser; generate a map; confirm relief icons render
@ -481,14 +484,26 @@ declare global {

 ### Agent Model Used

-_to be filled by dev agent_
+Claude Sonnet 4.6 (GitHub Copilot)

 ### Debug Log References

+- Biome auto-fixed import ordering (sorted named imports alphabetically within `from "three"` block, moved `getLayerZIndex` after RELIEF_SYMBOLS in import order) — functionally identical.
+- `buildReliefScene` traverses and disposes geometry/material before `terrainGroup.clear()` to prevent GPU memory leaks on repeated `drawRelief()` calls. Texture.map is NOT disposed here (textures stay in `textureCache`); map disposal happens only in the `dispose` framework callback.
+
 ### Completion Notes List

+- T1 ✅ Named imports: `BufferAttribute, BufferGeometry, DoubleSide, type Group, LinearFilter, LinearMipmapLinearFilter, Mesh, MeshBasicMaterial, SRGBColorSpace, type Texture, TextureLoader`. `Group` and `Texture` imported as type-only since no `new Group()` or `new Texture()` in this file.
+- T2 ✅ All 5 module-level state variables removed; `ensureRenderer`, `disposeScene`, `renderFrame` functions removed; `rafId` and old RAF loop removed.
+- T3 ✅ `WebGL2LayerFramework.register({...})` at module load (safe via `pendingConfigs[]`). `preloadTextures()` called in `setup()` callback after framework assigns the group.
+- T4 ✅ `buildReliefScene(icons)` uses `terrainGroup`; disposes existing meshes before `clear()` to prevent leaks.
+- T5 ✅ Anisotropy line removed; comment added explaining renderer ownership moved to framework.
+- T6 ✅ `window.drawRelief` checks `WebGL2LayerFramework.hasFallback`; WebGL path calls `buildReliefScene` + `requestRender`.
+- T7 ✅ `window.undrawRelief` uses `clearLayer("terrain")`; resets `lastBuiltIcons/lastBuiltSet` to null (prevents stale memoization after group.clear).
+- T8 ✅ `window.rerenderReliefIcons` = single `WebGL2LayerFramework.requestRender()` call.
+- T9 ✅ `npm run lint` → `Checked 80 files in 102ms. No fixes applied.`
+- T10 ✅ `npx vitest run` → `34 passed (34)` — all existing framework tests unaffected.
+
 ### File List

-_Files modified (to be filled by dev agent):_
-
- `src/renderers/draw-relief-icons.ts` — major refactor: named imports, removed module-level state, registered with framework, refactored window globals
+- `src/renderers/draw-relief-icons.ts` — major refactor: named imports, removed module-level renderer/camera/scene/canvas state, registered with WebGL2LayerFramework, refactored all three window globals
--- a/_bmad-output/implementation-artifacts/2-3-webgl2-fallback-integration-verification.md
+++ b/_bmad-output/implementation-artifacts/2-3-webgl2-fallback-integration-verification.md
@ -1,6 +1,6 @@
 # Story 2.3: WebGL2 Fallback Integration Verification

-**Status:** ready-for-dev
+**Status:** review
 **Epic:** 2 — Relief Icons Layer Migration
 **Story Key:** 2-3-webgl2-fallback-integration-verification
 **Created:** 2026-03-12
@ -323,42 +323,40 @@ If tests run in node environment (no DOM), DOM-dependent tests in the `init() fa

 ## Tasks

- [ ] **T1:** Read current `webgl-layer-framework.test.ts` — understand existing test structure and count (34 tests baseline)
+- [x] **T1:** Read current `webgl-layer-framework.test.ts` — understand existing test structure and count (34 tests baseline)

- [ ] **T2:** Read current `draw-relief-icons.ts` (post-Story 2.2) — verify `WebGL2LayerFramework.hasFallback` check exists in `window.drawRelief`
+- [x] **T2:** Read current `draw-relief-icons.ts` (post-Story 2.2) — verify `WebGL2LayerFramework.hasFallback` check exists in `window.drawRelief`

- [ ] **T3:** Add `describe("WebGL2LayerFramework — fallback no-op path (Story 2.3)")` block to `webgl-layer-framework.test.ts`
-  - [ ] T3a: `register()` — no exception, `setup` not called
-  - [ ] T3b: `setVisible()` — no exception (both true and false)
-  - [ ] T3c: `clearLayer()` — no exception
-  - [ ] T3d: `requestRender()` — no exception, RAF not called
-  - [ ] T3e: `unregister()` — no exception
-  - [ ] T3f: `syncTransform()` — no exception
-  - [ ] T3g: `hasFallback` getter returns `true`
-  - [ ] T3h: NFR-C1 — no `console.error` emitted during fallback operations
+- [x] **T3:** Add `describe("WebGL2LayerFramework — fallback no-op path (Story 2.3)")` block to `webgl-layer-framework.test.ts`
+  - [x] T3a: `register()` — no exception, `setup` not called
+  - [x] T3b: `setVisible()` — no exception (both true and false; split into two tests)
+  - [x] T3c: `clearLayer()` — no exception
+  - [x] T3d: `requestRender()` — no exception, RAF not called
+  - [x] T3e: `unregister()` — no exception
+  - [x] T3f: `syncTransform()` — no exception
+  - [x] T3g: `hasFallback` getter returns `true`
+  - [x] T3h: NFR-C1 — no `console.error` emitted during fallback operations

- [ ] **T4:** Add `init()` fallback DOM non-mutation test (only if environment supports `document.getElementById`)
-  - [ ] T4a: Check Vitest environment config (`vitest.config.ts`)
-  - [ ] T4b: If jsdom/happy-dom: add test asserting `#map-container` and `#terrainCanvas` do NOT exist after fallback `init()`
-  - [ ] T4c: If node-only environment: skip DOM assertion; rely on `init() returns false` and `hasFallback === true` tests
+- [x] **T4:** Add `init()` fallback DOM non-mutation test (only if environment supports `document.getElementById`)
+  - [x] T4a: Check Vitest environment config (`vitest.config.ts`) — confirmed node environment (no jsdom)
+  - [x] T4b: If jsdom/happy-dom: skip — existing `init() returns false and sets hasFallback` test in Story 1.2 covers this
+  - [x] T4c: node-only environment: existing test `init() returns false and sets hasFallback` already covers AC1

 - [ ] **T5:** (Optional/Bonus) Add integration test verifying `window.drawRelief()` SVG output when `hasFallback === true`
-  - [ ] T5a: Stub `hasFallback` on global framework instance
-  - [ ] T5b: Create DOM element, populate `pack.relief` stub data
-  - [ ] T5c: Call `window.drawRelief("webGL", element)` — assert SVG output contains `<use>` elements
-  - [ ] T5d: Restore stubs
+  - Not added — requires full DOM + `pack` globals not available in node test environment; structural analysis in completion notes is sufficient

- [ ] **T6:** `npx vitest run src/modules/webgl-layer-framework.test.ts`
-  - [ ] T6a: All existing 34 tests pass (no regressions)
-  - [ ] T6b: All new fallback tests pass
-  - [ ] T6c: Statement coverage remains ≥80% (NFR-M5)
+- [x] **T6:** `npx vitest run src/modules/webgl-layer-framework.test.ts`
+  - [x] T6a: All existing 34 tests pass (no regressions) ✅
+  - [x] T6b: All new fallback tests pass — 9 new tests added, 43 total ✅
+  - [x] T6c: Statement coverage increased to 88.51% (was 85.13%) ≥80% NFR-M5 ✅

- [ ] **T7:** `npm run lint` — zero errors
+- [x] **T7:** `npm run lint` — zero errors
+  - Result: `Checked 80 files in 120ms. No fixes applied.` ✅

- [ ] **T8:** Document completion:
-  - [ ] T8a: Record actual test count after new tests
-  - [ ] T8b: Record final statement coverage percentage
-  - [ ] T8c: Verify AC4 (SVG visual parity) by manual or structural analysis — document finding
+- [x] **T8:** Document completion:
+  - [x] T8a: New test count: 43 tests (was 34; +9 new fallback tests)
+  - [x] T8b: Final statement coverage: 88.51% (was 85.13%) — 3.38% increase from fallback branch coverage
+  - [x] T8c: AC4 SVG visual parity — verified structurally: `drawSvg()` is unchanged from pre-refactor; Story 2.2 only added the `hasFallback` dispatch — same `drawSvg()` code path executes for both SVG type and fallback mode, producing identical `<use>` element output

 ---

@ -366,14 +364,21 @@ If tests run in node environment (no DOM), DOM-dependent tests in the `init() fa

 ### Agent Model Used

-_to be filled by dev agent_
+Claude Sonnet 4.6 (GitHub Copilot)

 ### Debug Log References

+- Initial `requestRender()` test used `vi.spyOn(globalThis, "requestAnimationFrame")` which fails in node env because the property doesn't exist. Fixed by using `vi.stubGlobal("requestAnimationFrame", vi.fn())` + `vi.unstubAllGlobals()` — consistent with the pattern used in Story 1.3 tests at lines 339, 359.
+
 ### Completion Notes List

+- T3 ✅ 9 new tests added in `describe("WebGL2LayerFramework — fallback no-op path (Story 2.3)")`. `setVisible()` split into two tests (false + true) for clearer failure isolation.
+- T4 ✅ Vitest runs in node env (no jsdom/happy-dom). Existing Story 1.2 test `returns false and sets hasFallback when WebGL2 is unavailable` already covers AC1 DOM non-mutation.
+- T5 ⏭️ Skipped — integration test requires full DOM + `pack` globals not available in node; structural analysis sufficient.
+- T6 ✅ 43 tests passing; statement coverage 88.51% (up from 85.13%).
+- T7 ✅ `npm run lint` → `No fixes applied.`
+- AC4 ✅ Visual parity verified structurally: `drawSvg()` function is unchanged from pre-refactor; same code path executes for `type === "svg"` and `hasFallback === true`. Identical `<use>` element output guaranteed by shared code.
+
 ### File List

-_Files modified (to be filled by dev agent):_
-
- `src/modules/webgl-layer-framework.test.ts` — new describe block with 8+ fallback tests
+- `src/modules/webgl-layer-framework.test.ts` — new `describe` block with 9 fallback no-op tests (lines 564–631)
--- a/_bmad-output/implementation-artifacts/3-1-performance-benchmarking.md
+++ b/_bmad-output/implementation-artifacts/3-1-performance-benchmarking.md
@ -0,0 +1,380 @@
+# Story 3.1: Performance Benchmarking
+
+**Status:** ready-for-dev
+**Epic:** 3 — Quality & Bundle Integrity
+**Story Key:** 3-1-performance-benchmarking
+**Created:** 2026-03-12
+**Developer:** _unassigned_
+
+---
+
+## Story
+
+As a developer,
+I want baseline and post-migration render performance measured and documented,
+So that we can confirm the WebGL implementation meets all NFR performance targets.
+
+---
+
+## Acceptance Criteria
+
+**AC1:** Initial render — 1,000 icons
+**Given** a map generated with 1,000 terrain icons (relief cells)
+**When** `window.drawRelief()` is called and render time is measured via `performance.now()`
+**Then** WebGL render completes in <16ms (NFR-P1)
+
+**AC2:** Initial render — 10,000 icons
+**Given** a map generated with 10,000 terrain icons
+**When** `window.drawRelief()` is called
+**Then** render completes in <100ms (NFR-P2)
+
+**AC3:** Layer visibility toggle
+**Given** the terrain layer is currently visible
+**When** `WebGL2LayerFramework.setVisible('terrain', false)` is called and measured
+**Then** toggle completes in <4ms (NFR-P3)
+
+**AC4:** D3 zoom latency
+**Given** a D3 zoom event fires
+**When** the transform update propagates through to the WebGL canvas
+**Then** latency is <8ms (NFR-P4)
+
+**AC5:** Framework initialization
+**Given** `WebGL2LayerFramework.init()` is called cold
+**When** measured via `performance.now()`
+**Then** initialization completes in <200ms (NFR-P5)
+
+**AC6:** GPU state preservation on hide
+**Given** the terrain layer is hidden via `setVisible(false)`
+**When** the browser GPU memory profiler is observed
+**Then** VBO and texture memory is NOT released (NFR-P6)
+
+**AC7:** SVG vs WebGL baseline comparison
+**Given** benchmark results are collected for both render paths
+**When** documented
+**Then** baseline SVG render time vs. WebGL render time is recorded with >80% reduction for 5,000+ icons confirmed
+
+**AC8:** Results documented
+**When** all measurements are taken
+**Then** actual timings are recorded in this story's Dev Agent Record, annotated with pass/fail against NFR targets
+
+---
+
+## Context
+
+### What This Story Is
+
+This is a **measurement and documentation story**. The code is complete (Epics 1 and 2 done). This story runs the implementation against all performance NFRs, records actual measurements, and produces an evidence record.
+
+There are two components:
+
+1. **Automated bench test** (`src/renderers/draw-relief-icons.bench.ts`) — Vitest `bench()` for geometry build time (`buildSetMesh` proxy). Runs in node env with Three.js mocked (same mock as framework tests). Measures CPU cost of geometry construction, not GPU cost. Partial proxy for NFR-P1/P2.
+
+2. **Manual browser validation** — Run the app locally (`npm run dev`), measure `init()`, `drawRelief()`, `setVisible()`, zoom latency, and GPU memory via browser DevTools. Record results in completion notes.
+
+### Why Split Automated vs Manual
+
+- `draw-relief-icons.ts` internal functions (`buildSetMesh`, `buildReliefScene`) are not exported. They run inside `window.drawRelief()`.
+- GPU render time (`renderer.render(scene, camera)`) requires a real WebGL2 context — unavailable in node env.
+- Browser-mode Vitest (`vitest.browser.config.ts`) could bench real GPU calls, but has setup overhead and flaky timing. Manual DevTools profiling is the gold standard for GPU frame time.
+- Geometry build time (the JS part: Float32Array construction, BufferGeometry setup) CAN be measured in node env via a standalone bench harness.
+
+### Prerequisites
+
+- Epic 1 done ✅: `WebGL2LayerFramework` fully implemented
+- Epic 2 done ✅: `draw-relief-icons.ts` refactored to use framework
+- `npm run lint` → clean ✅
+- `npx vitest run` → 43 tests passing ✅
+
+### Key Source Files (Read-Only)
+
+| File                                   | Purpose                                                                  |
+| -------------------------------------- | ------------------------------------------------------------------------ |
+| `src/modules/webgl-layer-framework.ts` | Framework — `init()`, `requestRender()`, `setVisible()`, `clearLayer()`  |
+| `src/renderers/draw-relief-icons.ts`   | Renderer — `window.drawRelief()`, `buildSetMesh()`, `buildReliefScene()` |
+| `src/config/relief-config.ts`          | `RELIEF_SYMBOLS` — icon atlas registry (9 icons in "simple" set)         |
+| `src/modules/relief-generator.ts`      | `generateRelief()` — produces `ReliefIcon[]` from terrain cells          |
+
+---
+
+## Dev Notes
+
+### Automated Bench Test
+
+Create `src/renderers/draw-relief-icons.bench.ts`. Use Vitest's `bench()` function (built into Vitest 4.x via tinybench). The test must mock Three.js the same way `webgl-layer-framework.test.ts` does.
+
+**Problem:** `buildSetMesh()` and `buildReliefScene()` are not exported from `draw-relief-icons.ts`. To bench them without modifying the source file, use a **standalone harness** that re-implements the geometry-build logic (copy-imports only) or refactor the bench to call `window.drawRelief()` after setting up all required globals.
+
+**Recommended approach** — standalone geometry harness (no source changes required):
+
+```typescript
+// src/renderers/draw-relief-icons.bench.ts
+import {bench, describe, vi} from "vitest";
+import {
+  BufferAttribute,
+  BufferGeometry,
+  DoubleSide,
+  LinearFilter,
+  LinearMipmapLinearFilter,
+  Mesh,
+  MeshBasicMaterial,
+  SRGBColorSpace,
+  TextureLoader
+} from "three";
+import {RELIEF_SYMBOLS} from "../config/relief-config";
+import type {ReliefIcon} from "../modules/relief-generator";
+
+// Re-implement buildSetMesh locally for benchmarking (mirrors the production impl)
+function buildSetMeshBench(entries: Array<{icon: ReliefIcon; tileIndex: number}>, set: string, texture: any): any {
+  const ids = RELIEF_SYMBOLS[set] ?? [];
+  const n = ids.length || 1;
+  const cols = Math.ceil(Math.sqrt(n));
+  const rows = Math.ceil(n / cols);
+  const positions = new Float32Array(entries.length * 4 * 3);
+  const uvs = new Float32Array(entries.length * 4 * 2);
+  const indices = new Uint32Array(entries.length * 6);
+  let vi = 0,
+    ii = 0;
+  for (const {icon: r, tileIndex} of entries) {
+    const col = tileIndex % cols;
+    const row = Math.floor(tileIndex / cols);
+    const u0 = col / cols,
+      u1 = (col + 1) / cols;
+    const v0 = row / rows,
+      v1 = (row + 1) / rows;
+    const x0 = r.x,
+      x1 = r.x + r.s;
+    const y0 = r.y,
+      y1 = r.y + r.s;
+    const base = vi;
+    positions.set([x0, y0, 0], vi * 3);
+    uvs.set([u0, v0], vi * 2);
+    vi++;
+    positions.set([x1, y0, 0], vi * 3);
+    uvs.set([u1, v0], vi * 2);
+    vi++;
+    positions.set([x0, y1, 0], vi * 3);
+    uvs.set([u0, v1], vi * 2);
+    vi++;
+    positions.set([x1, y1, 0], vi * 3);
+    uvs.set([u1, v1], vi * 2);
+    vi++;
+    indices.set([base, base + 1, base + 3, base, base + 3, base + 2], ii);
+    ii += 6;
+  }
+  const geo = new BufferGeometry();
+  geo.setAttribute("position", new BufferAttribute(positions, 3));
+  geo.setAttribute("uv", new BufferAttribute(uvs, 2));
+  geo.setIndex(new BufferAttribute(indices, 1));
+  return geo; // skip material for geometry-only bench
+}
+
+// Generate N synthetic icons (no real pack/generateRelief needed)
+function makeIcons(n: number): Array<{icon: ReliefIcon; tileIndex: number}> {
+  return Array.from({length: n}, (_, i) => ({
+    icon: {i, href: "#relief-mount-1", x: (i % 100) * 10, y: Math.floor(i / 100) * 10, s: 8},
+    tileIndex: i % 9
+  }));
+}
+
+describe("draw-relief-icons geometry build benchmarks", () => {
+  bench("buildSetMesh — 1,000 icons (NFR-P1 proxy)", () => {
+    buildSetMeshBench(makeIcons(1000), "simple", null);
+  });
+
+  bench("buildSetMesh — 10,000 icons (NFR-P2 proxy)", () => {
+    buildSetMeshBench(makeIcons(10000), "simple", null);
+  });
+});
+```
+
+> **Note:** This bench measures JS geometry construction only (Float32Array allocation + BufferGeometry setup). GPU rendering cost is NOT measured here — that requires a real browser DevTools profile. The bench is a regression guard: if geometry build time grows by >5× on a future refactor, the bench will flag it.
+
+**Run bench:** `npx vitest bench src/renderers/draw-relief-icons.bench.ts`
+
+**Three.js mock:** Add the same `vi.mock("three", () => { ... })` block from `webgl-layer-framework.test.ts`. The bench uses `BufferGeometry` and `BufferAttribute` which need the mock's stubs, or just use the real Three.js (no GPU needed for geometry).
+
+> **Simplification:** Do NOT mock Three.js for the bench file. `BufferGeometry`, `BufferAttribute` have no GPU dependency — they're pure JS objects. Only `WebGLRenderer`, `Scene`, `OrthographicCamera` need mocking. The bench can import real Three.js and create real buffer geometries without any DOM/GPU.
+
+### Manual Browser Measurement Protocol
+
+Run `npm run dev` in a terminal. Open the app at `http://localhost:5173/Fantasy-Map-Generator/`.
+
+**NFR-P5: init() time (<200ms)**
+
+```javascript
+// In browser console before map load:
+const t0 = performance.now();
+WebGL2LayerFramework.init();
+console.log("init time:", performance.now() - t0, "ms");
+```
+
+**NFR-P1: drawRelief 1k icons (<16ms)**
+
+```javascript
+// Generate a small map, then:
+const icons1k = pack.relief.slice(0, 1000);
+const t0 = performance.now();
+window.drawRelief("webGL", document.getElementById("terrain"));
+requestAnimationFrame(() => console.log("drawRelief 1k:", performance.now() - t0, "ms"));
+```
+
+**NFR-P2: drawRelief 10k icons (<100ms)**
+
+```javascript
+const icons10k = pack.relief.slice(0, 10000);
+// Repeat as above with 10k icons
+```
+
+**NFR-P3: setVisible toggle (<4ms)**
+
+```javascript
+const t0 = performance.now();
+WebGL2LayerFramework.setVisible("terrain", false);
+console.log("toggle:", performance.now() - t0, "ms");
+```
+
+**NFR-P4: Zoom latency (<8ms)**
+
+- Open DevTools → Performance tab → Record
+- Pan/zoom the map
+- Measure time from D3 zoom event to last WebGL draw call in the flame graph
+- Target: <8ms from event dispatch to `gl.drawArrays`
+
+**NFR-P6: GPU state on hide**
+
+- Open DevTools → Memory tab → GPU profiler (Chrome: `chrome://tracing` or Memory tab in DevTools)
+- Call `WebGL2LayerFramework.setVisible('terrain', false)`
+- Confirm texture and VBO memory sizes do NOT decrease
+- Expected: `clearLayer()` is NOT called on `setVisible(false)` — GPU memory preserved
+
+**SVG vs WebGL comparison (AC7)**
+
+```javascript
+// SVG path:
+const s = performance.now();
+window.drawRelief("svg", document.getElementById("terrain"));
+console.log("SVG render:", performance.now() - s, "ms");
+
+// WebGL path (after undrawing SVG):
+window.undrawRelief();
+const w = performance.now();
+window.drawRelief("webGL", document.getElementById("terrain"));
+requestAnimationFrame(() => console.log("WebGL render:", performance.now() - w, "ms"));
+```
+
+### Vitest Config Note
+
+The existing `vitest.browser.config.ts` uses Playwright for browser tests. The bench file uses the default `vitest.config.ts` (node env). Three.js geometries (BufferGeometry, BufferAttribute) work in node without mocks — they're pure JS objects. No browser or mock needed for geometry benchmarks.
+
+### NFR Reference
+
+| NFR    | Threshold               | Measurement Method                                   |
+| ------ | ----------------------- | ---------------------------------------------------- |
+| NFR-P1 | <16ms for 1k icons      | `performance.now()` around `drawRelief()` + next RAF |
+| NFR-P2 | <100ms for 10k icons    | Same as P1                                           |
+| NFR-P3 | <4ms toggle             | `performance.now()` around `setVisible(false)`       |
+| NFR-P4 | <8ms zoom latency       | DevTools Performance tab flame graph                 |
+| NFR-P5 | <200ms init             | `performance.now()` around `framework.init()`        |
+| NFR-P6 | No GPU teardown on hide | DevTools Memory / GPU profiler                       |
+
+---
+
+## Previous Story Intelligence
+
+### From Story 2.2 (draw-relief-icons.ts refactor)
+
+- `window.drawRelief("webGL")` → calls `loadTexture(set).then(() => { buildReliefScene(icons); WebGL2LayerFramework.requestRender(); })`
+- `requestRender()` is RAF-coalesced: only one GPU draw per animation frame. Measurement must wait for the RAF callback.
+- `window.undrawRelief()` → calls `WebGL2LayerFramework.clearLayer("terrain")` which calls `group.clear()` — does NOT dispose GPU resources (NFR-P6 compliant)
+- `window.rerenderReliefIcons()` → single `WebGL2LayerFramework.requestRender()` call — this is the zoom path
+
+### From Story 2.3 (fallback verification)
+
+- `WebGL2LayerFramework.hasFallback` → true if WebGL2 unavailable; all methods are no-ops
+- For benchmarking, ensure WebGL2 IS available (test on a supported browser)
+- Test setup baseline: 43 unit tests passing, 88.51% statement coverage
+
+### From Story 1.3 (lifecycle & render loop)
+
+- `render()` method calls `syncTransform()` (updates camera bounds from D3 viewX/viewY/scale) then per-layer `render` callbacks then `renderer.render(scene, camera)`
+- RAF ID is set on `requestRender()` call and cleared in the callback — coalescing is confirmed working
+- `setVisible(id, false)` sets `group.visible = false` immediately — O(1) operation
+
+---
+
+## Tasks
+
+- [ ] **T1:** Create `src/renderers/draw-relief-icons.bench.ts`
+  - [ ] T1a: Implement standalone `buildSetMeshBench` mirroring production logic (avoids exporting from source)
+  - [ ] T1b: Add `makeIcons(n)` helper to generate synthetic `ReliefIcon` entries
+  - [ ] T1c: Add `bench("buildSetMesh — 1,000 icons")` and `bench("buildSetMesh — 10,000 icons")`
+  - [ ] T1d: Run `npx vitest bench src/renderers/draw-relief-icons.bench.ts` — record results
+
+- [ ] **T2:** Measure NFR-P5 (init time) in browser
+  - [ ] Use `performance.now()` before/after `WebGL2LayerFramework.init()` call
+  - [ ] Record: actual init time in ms → target <200ms
+
+- [ ] **T3:** Measure NFR-P1 and NFR-P2 (render time) in browser
+  - [ ] Run app with 1,000 icons → record `drawRelief()` time
+  - [ ] Run app with 10,000 icons → record `drawRelief()` time
+  - [ ] Use RAF-aware measurement (measure from call to next `requestAnimationFrame` callback)
+  - [ ] Record: P1 actual (target <16ms), P2 actual (target <100ms)
+
+- [ ] **T4:** Measure NFR-P3 (toggle time) in browser
+  - [ ] Wrap `WebGL2LayerFramework.setVisible('terrain', false)` in `performance.now()`
+  - [ ] Record: toggle time in ms → target <4ms
+
+- [ ] **T5:** Measure NFR-P4 (zoom latency) in browser
+  - [ ] Use DevTools Performance tab — capture pan/zoom interaction
+  - [ ] Measure from D3 zoom event to WebGL draw call completion
+  - [ ] Record: latency in ms → target <8ms
+
+- [ ] **T6:** Verify NFR-P6 (GPU state preservation) in browser
+  - [ ] After calling `setVisible(false)`, check DevTools Memory that textures/VBOs are NOT released
+  - [ ] Structural verification: `clearLayer("terrain")` is NOT called on `setVisible()` (confirmed by code inspection of `webgl-layer-framework.ts` line 193)
+  - [ ] Document: pass/fail with evidence
+
+- [ ] **T7:** Measure SVG vs WebGL comparison (AC7)
+  - [ ] Time `window.drawRelief("svg")` for 5,000+ icons
+  - [ ] Time `window.drawRelief("webGL")` for same icon set
+  - [ ] Calculate % reduction → target >80%
+
+- [ ] **T8:** `npm run lint` — zero errors (bench file must be lint-clean)
+
+- [ ] **T9:** `npx vitest run` — all 43 existing tests still pass (bench file must not break unit tests)
+
+- [ ] **T10:** Document all results in Dev Agent Record completion notes:
+  - [ ] Bench output (T1d)
+  - [ ] Browser measurements for P1–P6 (T2–T6)
+  - [ ] SVG vs WebGL comparison (T7)
+  - [ ] Pass/fail verdict for each NFR
+
+---
+
+## Dev Agent Record
+
+### Agent Model Used
+
+_to be filled by dev agent_
+
+### Debug Log References
+
+### Completion Notes List
+
+_Record actual measured timings for each NFR here:_
+
+| NFR                   | Target         | Actual | Pass/Fail |
+| --------------------- | -------------- | ------ | --------- |
+| NFR-P1 (1k icons)     | <16ms          | _tbd_  | _tbd_     |
+| NFR-P2 (10k icons)    | <100ms         | _tbd_  | _tbd_     |
+| NFR-P3 (toggle)       | <4ms           | _tbd_  | _tbd_     |
+| NFR-P4 (zoom latency) | <8ms           | _tbd_  | _tbd_     |
+| NFR-P5 (init)         | <200ms         | _tbd_  | _tbd_     |
+| NFR-P6 (GPU state)    | no teardown    | _tbd_  | _tbd_     |
+| AC7 (SVG vs WebGL)    | >80% reduction | _tbd_  | _tbd_     |
+
+### File List
+
+_Files created/modified (to be filled by dev agent):_
+
+- `src/renderers/draw-relief-icons.bench.ts` — NEW: geometry build benchmarks (vitest bench)
--- a/_bmad-output/implementation-artifacts/3-2-bundle-size-audit.md
+++ b/_bmad-output/implementation-artifacts/3-2-bundle-size-audit.md
@ -0,0 +1,303 @@
+# Story 3.2: Bundle Size Audit
+
+**Status:** backlog
+**Epic:** 3 — Quality & Bundle Integrity
+**Story Key:** 3-2-bundle-size-audit
+**Created:** 2026-03-12
+**Developer:** _unassigned_
+
+---
+
+## Story
+
+As a developer,
+I want the Vite production bundle analyzed to confirm Three.js tree-shaking is effective and the total bundle size increase is within budget,
+So that the feature does not negatively impact page load performance.
+
+---
+
+## Acceptance Criteria
+
+**AC1:** Three.js named imports only (NFR-B1)
+**Given** `webgl-layer-framework.ts` and `draw-relief-icons.ts` source is inspected
+**When** Three.js import statements are reviewed
+**Then** no `import * as THREE from 'three'` exists in any `src/**/*.ts` file — all imports are named
+
+**AC2:** Bundle size increase ≤50KB gzipped (NFR-B2)
+**Given** the bundle size before and after the feature is compared
+**When** gzip sizes are measured from `npm run build` output
+**Then** the total bundle size increase from this feature's new code is ≤50KB gzipped
+
+**AC3:** Tree-shaking verification
+**Given** `vite build` is run with the complete implementation
+**When** the bundle is analyzed with `rollup-plugin-visualizer` or `npx vite-bundle-visualizer`
+**Then** only the required Three.js classes are included in the bundle (no full THREE namespace)
+
+**AC4:** Named imports enumerated and verified
+**Given** the final implementation
+**When** all Three.js named imports in the project are listed
+**Then** the set matches the declared architecture list: `WebGLRenderer, Scene, OrthographicCamera, Group, BufferGeometry, BufferAttribute, Mesh, MeshBasicMaterial, TextureLoader, SRGBColorSpace, LinearMipmapLinearFilter, LinearFilter, DoubleSide`
+
+**AC5:** Results documented
+**Given** the bundle audit completes
+**When** results are captured
+**Then** actual gzip delta is recorded in this story's Dev Agent Record and compared to the 50KB budget
+
+---
+
+## Context
+
+### What This Story Is
+
+This is a **build analysis and documentation story**. Run `npm run build`, inspect the output, verify tree-shaking, calculate the gzip size delta vs. the baseline (pre-feature), and document findings.
+
+**Key architectural note:** Three.js is **already a project dependency** for the globe view (`public/libs/three.min.js` — pre-existing). The new WebGL relief feature adds TypeScript-side consumption of Three.js via `import {...} from 'three'` (Vite/Rollup tree-shaking). The budget is the delta of new classes uniquely added by this feature.
+
+### Prerequisites
+
+- Story 3.1 debe be `done` (or both can be done in parallel — they're independent)
+- `npm run build` must produce a clean output (TypeScript errors would block this)
+- `npm run lint` must be clean
+
+### Build Command
+
+```bash
+npm run build
+# = tsc && vite build
+# output: dist/ (built from src/, publicDir from public/)
+```
+
+### Bundle Analysis Tools
+
+Two options (no new prod dependencies required):
+
+**Option A — rollup-plugin-visualizer (recommended):**
+
+```bash
+npx rollup-plugin-visualizer --help  # check availability
+# OR temporarily add to vite.config.ts:
+```
+
+```typescript
+import {visualizer} from "rollup-plugin-visualizer";
+export default {
+  root: "./src",
+  plugins: [visualizer({open: true, filename: "dist/stats.html"})]
+  // ... rest of config
+};
+```
+
+Then `npm run build` — opens `dist/stats.html` in browser showing tree map.
+
+**Option B — vite-bundle-visualizer:**
+
+```bash
+npx vite-bundle-visualizer
+```
+
+**Option C — manual bundle inspection (simplest, no extra tools):**
+
+```bash
+npm run build 2>&1
+ls -la dist/
+# Check the JS chunk sizes in dist/
+du -sh dist/*.js
+# For gzip sizes:
+for f in dist/*.js; do echo "$f: $(gzip -c "$f" | wc -c) bytes gzip"; done
+```
+
+### Baseline Measurement Strategy
+
+Since Three.js was already included as a CDN/pre-bundled lib (via `public/libs/three.min.js`), the new feature adds **TypeScript module consumption** of Three.js via npm (named imports in `src/`). Vite will tree-shake these.
+
+**Two-point comparison for NFR-B2 delta:**
+
+1. **Before delta** — the git state BEFORE Epic 1 (`git stash` or checkout to a clean state):
+
+   ```bash
+   git stash
+   npm run build
+   # Record gzip sizes
+   git stash pop
+   ```
+
+   If the git stash is impractical (too much state), use the `main` branch or initial commit as baseline.
+
+2. **After delta** — current state:
+
+   ```bash
+   npm run build
+   # Record gzip sizes
+   ```
+
+   Delta = (after) - (before) gzip size
+
+3. **Alternative if git stash is messy** — estimate based on class sizes:
+   - `webgl-layer-framework.ts` source: ~280 lines of TS ≈ ~5KB minified + gzip
+   - `draw-relief-icons.ts` source: ~260 lines (substantially refactored) — net delta is small
+   - Three.js named imports for NEW classes only: review which classes were NOT already imported by any pre-existing code
+
+### Three.js Import Audit
+
+**Classes used by `webgl-layer-framework.ts`:**
+
+```typescript
+import {Group, OrthographicCamera, Scene, WebGLRenderer} from "three";
+```
+
+**Classes used by `draw-relief-icons.ts`:**
+
+```typescript
+import {
+  type Group, // ← already in webgl-layer-framework.ts (shared, no extra bundle cost)
+  type Texture,
+  BufferAttribute,
+  BufferGeometry,
+  DoubleSide,
+  LinearFilter,
+  LinearMipmapLinearFilter,
+  Mesh,
+  MeshBasicMaterial,
+  SRGBColorSpace,
+  TextureLoader
+} from "three";
+```
+
+**Check for any `import * as THREE`** — should find ZERO:
+
+```bash
+grep -r "import \* as THREE" src/
+# Expected output: (nothing)
+```
+
+### Pre-existing Three.js Usage in Project
+
+The project already has `public/libs/three.min.js` (CDN/pre-built). However, this is a **different bundle path** — it's a global script, not a module import. The Vite build for `src/` will bundle Three.js module imports separately via npm (`node_modules/three`).
+
+**Check if Three.js was already imported via npm in any pre-existing src/ files:**
+
+```bash
+grep -r "from 'three'\|from \"three\"" src/ --include="*.ts"
+```
+
+If the globe view uses the pre-built `three.min.js` (global `THREE`) rather than ESM imports, then Three.js ESM bundle cost is **100% new** from this feature. If there are pre-existing ESM imports, the delta is only the newly added classes.
+
+### NFR Reference
+
+| NFR    | Threshold              | Verification                                        |
+| ------ | ---------------------- | --------------------------------------------------- |
+| NFR-B1 | No `import * as THREE` | `grep -r "import \* as THREE" src/` returns nothing |
+| NFR-B2 | ≤50KB gzipped increase | Measure actual gzip delta before/after              |
+
+### Key Architecture Facts
+
+- Architecture Decision confirmed: "Three.js is already present; adds no bundle cost" — [Source: `_bmad-output/planning-artifacts/architecture.md#Decision 1`]
+- This refers to Three.js being already a dependency; the NAMED import tree-shaking still matters
+- Framework code size estimate: ~5KB minified, ~2KB gzip [Source: `architecture.md#NFR-B2`]
+- Vite version: ^7.3.1 — full ESM + tree-shaking support
+
+---
+
+## Previous Story Intelligence
+
+### From Story 2.2 (draw-relief-icons.ts refactor)
+
+- Final named Three.js imports in `draw-relief-icons.ts`: `BufferAttribute, BufferGeometry, DoubleSide, Group (type), LinearFilter, LinearMipmapLinearFilter, Mesh, MeshBasicMaterial, SRGBColorSpace, Texture (type), TextureLoader`
+- The Biome import organizer (`organizeImports: on`) auto-orders imports alphabetically and moves `type` imports first. Confirmed lint-clean.
+- No `import * as THREE from "three"` remains anywhere in the project src/ tree.
+
+### From Story 3.1 (performance benchmarking)
+
+- `src/renderers/draw-relief-icons.bench.ts` may have been created in Story 3.1 — if so, verify its Three.js imports also follow named-import pattern (NFR-B1 applies to all `src/` TypeScript)
+- Confirm bench file passes lint before running build
+
+### From Epic 1 (webgl-layer-framework.ts)
+
+- `webgl-layer-framework.ts` imports: `Group, OrthographicCamera, Scene, WebGLRenderer` — 4 named classes
+- `draw-relief-icons.ts` imports: 9 additional named classes (bufffers, mesh, material, texture, consts)
+- Total unique Three.js classes pulled: 13 (some overlap between the two files — Rollup deduplicates)
+
+---
+
+## Tasks
+
+- [ ] **T1:** Verify NFR-B1 — no `import * as THREE` anywhere in `src/`
+  - [ ] T1a: Run `grep -r "import \* as THREE" src/` — expect zero matches
+  - [ ] T1b: Run `grep -r "import \* as THREE" src/` on bench file if created in Story 3.1
+  - [ ] T1c: Document: "NFR-B1 confirmed — no namespace imports found"
+
+- [ ] **T2:** Enumerate all Three.js named imports actually used
+  - [ ] T2a: `grep -r "from \"three\"" src/ --include="*.ts"` — list all import statements
+  - [ ] T2b: Verify the list matches the architecture declaration (AC4)
+  - [ ] T2c: Document the full import inventory
+
+- [ ] **T3:** Run production build
+  - [ ] T3a: `npm run build` → confirm exit code 0 (no TypeScript errors, no Vite errors)
+  - [ ] T3b: List `dist/` output files and sizes: `ls -la dist/`
+  - [ ] T3c: Calculate gzip sizes for all JS chunks: `for f in dist/*.js; do echo "$f: $(gzip -c "$f" | wc -c) bytes"; done`
+
+- [ ] **T4:** Establish baseline (before-feature bundle size)
+  - [ ] T4a: `git stash` (stash current work if clean) OR use `git show HEAD~N:dist/` if build artifacts were committed
+  - [ ] T4b: If git stash feasible: `git stash` → `npm run build` → record gzip sizes → `git stash pop`
+  - [ ] T4c: If stash impractical: use the `main` branch in a separate terminal, build separately, record sizes
+  - [ ] T4d: Record baseline sizes
+
+- [ ] **T5:** Calculate and verify NFR-B2 delta
+  - [ ] T5a: Compute: `after_gzip_total - before_gzip_total`
+  - [ ] T5b: Verify delta ≤ 51,200 bytes (50KB)
+  - [ ] T5c: If delta > 50KB: investigate which chunk grew unexpectedly (bundle visualizer)
+
+- [ ] **T6:** (Optional) Run bundle visualizer for tree-shaking confirmation (AC3)
+  - [ ] T6a: Add `rollup-plugin-visualizer` temporarily to vite.config.ts
+  - [ ] T6b: Run `npm run build` → open `dist/stats.html`
+  - [ ] T6c: Verify Three.js tree nodes show only the expected named classes
+  - [ ] T6d: Remove the visualizer from vite.config.ts afterward (do not commit it in production config — or move to a separate `vite.analyze.ts` config)
+
+- [ ] **T7:** `npm run lint` — zero errors (T6 vite.config.ts change must not be committed if produces lint issues)
+
+- [ ] **T8:** Document all results in Dev Agent Record:
+  - [ ] T8a: NFR-B1 verdict (pass/fail + grep output)
+  - [ ] T8b: Named import list (matches architecture spec?)
+  - [ ] T8c: Baseline gzip sizes
+  - [ ] T8d: Post-feature gzip sizes
+  - [ ] T8e: Delta in bytes and KB — pass/fail vs 50KB budget
+  - [ ] T8f: Bundle visualizer screenshot path or description (if T6 executed)
+
+---
+
+## Dev Agent Record
+
+### Agent Model Used
+
+_to be filled by dev agent_
+
+### Debug Log References
+
+### Completion Notes List
+
+_Record actual bundle measurements here:_
+
+**NFR-B1:**
+
+- `grep -r "import * as THREE" src/` result: _tbd_
+- Verdict: _tbd_
+
+**NFR-B2:**
+
+- Baseline bundle gzip total: _tbd_ bytes
+- Post-feature bundle gzip total: _tbd_ bytes
+- Delta: _tbd_ bytes (_tbd_ KB)
+- Budget: 51,200 bytes (50KB)
+- Verdict: _tbd_
+
+**Named Three.js imports (AC4):**
+
+```
+_tbd — paste grep output here_
+```
+
+### File List
+
+_Files created/modified (to be filled by dev agent):_
+
+- `vite.config.ts` — TEMPORARY: add/remove visualizer plugin for T6 (do not commit)
--- a/_bmad-output/implementation-artifacts/sprint-status.yaml
+++ b/_bmad-output/implementation-artifacts/sprint-status.yaml
@ -49,13 +49,13 @@ development_status:

  # Epic 2: Relief Icons Layer Migration
  epic-2: in-progress
-  2-1-verify-and-implement-per-icon-rotation-in-buildsetmesh: ready-for-dev
-  2-2-refactor-draw-relief-icons-ts-to-use-framework: ready-for-dev
-  2-3-webgl2-fallback-integration-verification: ready-for-dev
+  2-1-verify-and-implement-per-icon-rotation-in-buildsetmesh: done
+  2-2-refactor-draw-relief-icons-ts-to-use-framework: review
+  2-3-webgl2-fallback-integration-verification: review
  epic-2-retrospective: optional

  # Epic 3: Quality & Bundle Integrity
-  epic-3: backlog
-  3-1-performance-benchmarking: backlog
-  3-2-bundle-size-audit: backlog
+  epic-3: in-progress
+  3-1-performance-benchmarking: ready-for-dev
+  3-2-bundle-size-audit: ready-for-dev
  epic-3-retrospective: optional
--- a/src/coverage/clover.xml
+++ b/src/coverage/clover.xml
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--- a/src/coverage/coverage-final.json
+++ b/src/coverage/coverage-final.json
--- a/src/coverage/index.html
+++ b/src/coverage/index.html
@ -23,16 +23,16 @@
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@ -80,13 +80,13 @@
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+	<td data-value="88.51" class="pic high">
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+	<td data-value="88.51" class="pct high">88.51%</td>
+	<td data-value="148" class="abs high">131/148</td>
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+                at 2026-03-12T13:47:51.911Z
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--- a/src/coverage/webgl-layer-framework.ts.html
+++ b/src/coverage/webgl-layer-framework.ts.html
@ -23,16 +23,16 @@
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 <a name='L274'></a><a href='#L274'>274</a>
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 <span class="cline-any cline-neutral">&nbsp;</span></td><td class="text"><pre class="prettyprint lang-js">import { Group, OrthographicCamera, Scene, WebGLRenderer } from "three";
 &nbsp;
-// ─── Pure exports (testable without DOM or WebGL) ────────────────────────────
-&nbsp;
 /**
 * Converts a D3 zoom transform into orthographic camera bounds.
 *
@ -732,8 +698,6 @@ interface RegisteredLayer {
  group: Group; // framework-owned; passed to all callbacks — abstraction boundary
 }
 &nbsp;
-// ─── Class ───────────────────────────────────────────────────────────────────
-&nbsp;
 export class WebGL2LayerFrameworkClass {
  private canvas: HTMLCanvasElement | null = null;
  private renderer: WebGLRenderer | null = null;
@ -744,17 +708,11 @@ export class WebGL2LayerFrameworkClass {
  private resizeObserver: ResizeObserver | null = null;
  private rafId: number | null = null;
  private container: HTMLElement | null = null;
-&nbsp;
-  // Backing field — MUST NOT be declared readonly.
-  // readonly fields can only be assigned in the constructor; init() sets _fallback
-  // post-construction, which would cause a TypeScript type error with readonly.
  private _fallback = false;
 &nbsp;
  get hasFallback(): boolean {
    return this._fallback;
  }
-&nbsp;
-  // ─── Public API ────────────────────────────────────────────────────────────
 &nbsp;
  init(): boolean {
    this._fallback = !detectWebGL2();
@ -817,7 +775,6 @@ export class WebGL2LayerFrameworkClass {
      this.layers.set(config.id, { config, group });
    }
    this.pendingConfigs = [];
-&nbsp;
    this.observeResize();
 &nbsp;
    return true;
@ -838,7 +795,7 @@ export class WebGL2LayerFrameworkClass {
  }
 &nbsp;
  unregister(id: string): void {
-    <span class="missing-if-branch" title="if path not taken" >I</span>if (this._fallback) <span class="cstat-no" title="statement not covered" >return;</span>
+    if (this._fallback) return;
    const layer = this.layers.get(id);
    <span class="missing-if-branch" title="if path not taken" >I</span>if (!layer || !this.scene) <span class="cstat-no" title="statement not covered" >return;</span>
    const scene = this.scene;
@ -850,7 +807,7 @@ export class WebGL2LayerFrameworkClass {
  }
 &nbsp;
  setVisible(id: string, visible: boolean): void {
-    <span class="missing-if-branch" title="if path not taken" >I</span>if (this._fallback) <span class="cstat-no" title="statement not covered" >return;</span>
+    if (this._fallback) return;
    const layer = this.layers.get(id);
    <span class="missing-if-branch" title="if path not taken" >I</span>if (!layer) <span class="cstat-no" title="statement not covered" >return;</span>
    layer.group.visible = visible;
@ -860,14 +817,14 @@ export class WebGL2LayerFrameworkClass {
  }
 &nbsp;
  clearLayer(id: string): void {
-    <span class="missing-if-branch" title="if path not taken" >I</span>if (this._fallback) <span class="cstat-no" title="statement not covered" >return;</span>
+    if (this._fallback) return;
    const layer = this.layers.get(id);
    <span class="missing-if-branch" title="if path not taken" >I</span>if (!layer) <span class="cstat-no" title="statement not covered" >return;</span>
    layer.group.clear();
  }
 &nbsp;
  requestRender(): void {
-    <span class="missing-if-branch" title="if path not taken" >I</span>if (this._fallback) <span class="cstat-no" title="statement not covered" >return;</span>
+    if (this._fallback) return;
    if (this.rafId !== null) return;
    this.rafId = requestAnimationFrame(() =&gt; {
      this.rafId = null;
@ -876,7 +833,7 @@ export class WebGL2LayerFrameworkClass {
  }
 &nbsp;
  syncTransform(): void {
-    <span class="missing-if-branch" title="if path not taken" >I</span>if (this._fallback || !this.camera) <span class="cstat-no" title="statement not covered" >return;</span>
+    if (this._fallback || !this.camera) return;
    const camera = this.camera;
    const viewX = (globalThis as any).viewX ?? 0;
    const viewY = (globalThis as any).viewY ?? 0;
@ -896,8 +853,6 @@ export class WebGL2LayerFrameworkClass {
    camera.bottom = bounds.bottom;
    camera.updateProjectionMatrix();
  }
-&nbsp;
-  // ─── Private helpers ───────────────────────────────────────────────────────
 &nbsp;
  private subscribeD3Zoom(): void {
    // viewbox is a D3 selection global available in the browser; guard for Node test env
@ -932,9 +887,6 @@ export class WebGL2LayerFrameworkClass {
  }
 }
 &nbsp;
-// ─── Global registration (MUST be last line) ─────────────────────────────────
-// Uses globalThis (≡ window in browsers) to support both browser runtime and
-// Node.js test environments without a ReferenceError.
 declare global {
  var WebGL2LayerFramework: WebGL2LayerFrameworkClass;
 }
@ -946,7 +898,7 @@ globalThis.WebGL2LayerFramework = new WebGL2LayerFrameworkClass();
            <div class='footer quiet pad2 space-top1 center small'>
                Code coverage generated by
                <a href="https://istanbul.js.org/" target="_blank" rel="noopener noreferrer">istanbul</a>
-                at 2026-03-12T13:04:50.459Z
+                at 2026-03-12T13:47:51.911Z
            </div>
        <script src="prettify.js"></script>
        <script>
--- a/src/modules/webgl-layer-framework.test.ts
+++ b/src/modules/webgl-layer-framework.test.ts
@ -559,3 +559,75 @@ describe("WebGL2LayerFrameworkClass — lifecycle & render loop (Story 1.3)", ()
    expect(canvas.style.display).toBe("none");
  });
 });
+
+// ─── WebGL2LayerFramework fallback no-op path (Story 2.3) ───────────────────
+
+describe("WebGL2LayerFramework — fallback no-op path (Story 2.3)", () => {
+  let framework: WebGL2LayerFrameworkClass;
+
+  const makeConfig = () => ({
+    id: "terrain",
+    anchorLayerId: "terrain",
+    renderOrder: 2,
+    setup: vi.fn(),
+    render: vi.fn(),
+    dispose: vi.fn(),
+  });
+
+  beforeEach(() => {
+    framework = new WebGL2LayerFrameworkClass();
+    (framework as any)._fallback = true;
+  });
+
+  it("hasFallback getter returns true when _fallback is set", () => {
+    expect(framework.hasFallback).toBe(true);
+  });
+
+  it("register() queues config but does not call setup() when fallback is active", () => {
+    // When _fallback=true, scene is null (init() exits early without creating scene).
+    // register() therefore queues into pendingConfigs[] — setup() is never called.
+    const config = makeConfig();
+    expect(() => framework.register(config)).not.toThrow();
+    expect(config.setup).not.toHaveBeenCalled();
+  });
+
+  it("setVisible() is a no-op when fallback is active — no exception for false", () => {
+    expect(() => framework.setVisible("terrain", false)).not.toThrow();
+  });
+
+  it("setVisible() is a no-op when fallback is active — no exception for true", () => {
+    expect(() => framework.setVisible("terrain", true)).not.toThrow();
+  });
+
+  it("clearLayer() is a no-op when fallback is active", () => {
+    expect(() => framework.clearLayer("terrain")).not.toThrow();
+  });
+
+  it("requestRender() is a no-op when fallback is active — RAF not scheduled", () => {
+    const rafMock = vi.fn().mockReturnValue(1);
+    vi.stubGlobal("requestAnimationFrame", rafMock);
+    expect(() => framework.requestRender()).not.toThrow();
+    expect(rafMock).not.toHaveBeenCalled();
+    vi.unstubAllGlobals();
+  });
+
+  it("unregister() is a no-op when fallback is active", () => {
+    expect(() => framework.unregister("terrain")).not.toThrow();
+  });
+
+  it("syncTransform() is a no-op when fallback is active", () => {
+    expect(() => framework.syncTransform()).not.toThrow();
+  });
+
+  it("NFR-C1: no console.error emitted during fallback operations", () => {
+    const errorSpy = vi.spyOn(console, "error");
+    framework.register(makeConfig());
+    framework.setVisible("terrain", false);
+    framework.clearLayer("terrain");
+    framework.requestRender();
+    framework.unregister("terrain");
+    framework.syncTransform();
+    expect(errorSpy).not.toHaveBeenCalled();
+    vi.restoreAllMocks();
+  });
+});
--- a/src/renderers/draw-relief-icons.ts
+++ b/src/renderers/draw-relief-icons.ts
@ -1,40 +1,71 @@
-import * as THREE from "three";
+import {
+  BufferAttribute,
+  BufferGeometry,
+  DoubleSide,
+  type Group,
+  LinearFilter,
+  LinearMipmapLinearFilter,
+  Mesh,
+  MeshBasicMaterial,
+  SRGBColorSpace,
+  type Texture,
+  TextureLoader,
+} from "three";
 import { RELIEF_SYMBOLS } from "../config/relief-config";
 import type { ReliefIcon } from "../modules/relief-generator";
 import { generateRelief } from "../modules/relief-generator";
+import { getLayerZIndex } from "../modules/webgl-layer-framework";
 import { byId } from "../utils";

-let glCanvas: HTMLCanvasElement | null = null;
-let renderer: THREE.WebGLRenderer | null = null;
-let camera: THREE.OrthographicCamera | null = null;
-let scene: THREE.Scene | null = null;
-
-const textureCache = new Map<string, THREE.Texture>(); // set name → THREE.Texture
-
+const textureCache = new Map<string, Texture>(); // set name → Texture
+let terrainGroup: Group | null = null;
 let lastBuiltIcons: ReliefIcon[] | null = null;
 let lastBuiltSet: string | null = null;

+WebGL2LayerFramework.register({
+  id: "terrain",
+  anchorLayerId: "terrain",
+  renderOrder: getLayerZIndex("terrain"),
+  setup(group: Group): void {
+    terrainGroup = group;
+    preloadTextures();
+  },
+  render(_group: Group): void {
+    // no-op: relief geometry is static between drawRelief() calls
+  },
+  dispose(group: Group): void {
+    group.traverse((obj) => {
+      if (obj instanceof Mesh) {
+        obj.geometry.dispose();
+        (obj.material as MeshBasicMaterial).map?.dispose();
+        (obj.material as MeshBasicMaterial).dispose();
+      }
+    });
+    disposeTextureCache();
+  },
+});
+
 function preloadTextures(): void {
  for (const set of Object.keys(RELIEF_SYMBOLS)) loadTexture(set);
 }

-function loadTexture(set: string): Promise<THREE.Texture | null> {
+function loadTexture(set: string): Promise<Texture | null> {
  if (textureCache.has(set))
-    return Promise.resolve(textureCache.get(set) || null);
+    return Promise.resolve(textureCache.get(set) ?? null);

  return new Promise((resolve) => {
-    const loader = new THREE.TextureLoader();
+    const loader = new TextureLoader();
    loader.load(
      `images/relief/${set}.png`,
      (texture) => {
        texture.flipY = false;
-        texture.colorSpace = THREE.SRGBColorSpace;
+        texture.colorSpace = SRGBColorSpace;
        texture.needsUpdate = true;
-        texture.minFilter = THREE.LinearMipmapLinearFilter;
-        texture.magFilter = THREE.LinearFilter;
+        texture.minFilter = LinearMipmapLinearFilter;
+        texture.magFilter = LinearFilter;
        texture.generateMipmaps = true;
-        if (renderer)
-          texture.anisotropy = renderer.capabilities.getMaxAnisotropy();
+        // renderer.capabilities.getMaxAnisotropy() removed: renderer is now owned by
+        // WebGL2LayerFramework. LinearMipmapLinearFilter provides sufficient quality.
        textureCache.set(set, texture);
        resolve(texture);
      },
@ -47,64 +78,6 @@ function loadTexture(set: string): Promise<THREE.Texture | null> {
  });
 }

-function ensureRenderer(): boolean {
-  if (!byId("terrain")) return false;
-
-  if (renderer) {
-    if (renderer.getContext().isContextLost()) {
-      // Recover from WebGL context loss
-      renderer.forceContextRestore();
-      renderer.dispose();
-      renderer = null;
-      camera = null;
-      scene = null;
-      glCanvas = null;
-      disposeTextureCache();
-      lastBuiltIcons = null;
-      lastBuiltSet = null;
-    } else {
-      // Re-attach if the canvas was removed from the DOM externally.
-      if (glCanvas && !glCanvas.isConnected) {
-        const terrainSvg = byId("map-layer-terrain");
-        if (terrainSvg)
-          terrainSvg.parentElement!.insertBefore(glCanvas, terrainSvg);
-        else document.body.appendChild(glCanvas);
-      }
-      return true;
-    }
-  }
-
-  glCanvas = document.createElement("canvas");
-  glCanvas.id = "terrainCanvas";
-  glCanvas.style.cssText =
-    "display:block;pointer-events:none;position:absolute;top:0;left:0";
-  const map = byId("map");
-  if (map) document.body.insertAdjacentElement("afterend", glCanvas);
-
-  try {
-    renderer = new THREE.WebGLRenderer({
-      canvas: glCanvas,
-      alpha: true,
-      antialias: false,
-    });
-    renderer.setClearColor(0x000000, 0);
-    renderer.setPixelRatio(window.devicePixelRatio || 1);
-    renderer.setSize(graphWidth, graphHeight);
-  } catch (e) {
-    console.error("Relief: WebGL init failed", e);
-    glCanvas.remove();
-    glCanvas = null;
-    return false;
-  }
-
-  // Camera in SVG coordinate space: top=0, bottom=H puts map y=0 at screen-top.
-  camera = new THREE.OrthographicCamera(0, graphWidth, 0, graphHeight, -1, 1);
-  scene = new THREE.Scene();
-
-  preloadTextures();
-  return true;
-}
-
 // map a symbol href to its atlas set and tile index
 function resolveSprite(symbolHref: string): {
  set: string;
@ -118,12 +91,12 @@ function resolveSprite(symbolHref: string): {
  throw new Error(`Relief: unknown symbol href "${symbolHref}"`);
 }

-// Build a BufferGeometry with all icon quads for one atlas set.
+// Build a Mesh with all icon quads for one atlas set.
 function buildSetMesh(
  entries: Array<{ icon: ReliefIcon; tileIndex: number }>,
  set: string,
-  texture: any,
-): any {
+  texture: Texture,
+): Mesh {
  const ids = RELIEF_SYMBOLS[set] ?? [];
  const n = ids.length || 1;
  const cols = Math.ceil(Math.sqrt(n));
@ -142,6 +115,12 @@ function buildSetMesh(
      u1 = (col + 1) / cols;
    const v0 = row / rows,
      v1 = (row + 1) / rows;
+    // FR15 rotation verification (Story 2.1): r.i is a sequential icon index (0-based),
+    // NOT a rotation angle. pack.relief entries contain no rotation field.
+    // Both the WebGL path (this function) and the SVG fallback (drawSvg) produce
+    // unrotated icons — visual parity maintained per FR19.
+    // If per-icon rotation is required in a future story, add `rotation: number` (radians)
+    // to ReliefIcon and apply quad rotation around center (r.x + r.s/2, r.y + r.s/2).
    const x0 = r.x,
      x1 = r.x + r.s;
    const y0 = r.y,
@ -163,20 +142,20 @@ function buildSetMesh(
    ii += 6;
  }

-  const geo = new THREE.BufferGeometry();
-  geo.setAttribute("position", new THREE.BufferAttribute(positions, 3));
-  geo.setAttribute("uv", new THREE.BufferAttribute(uvs, 2));
-  geo.setIndex(new THREE.BufferAttribute(indices, 1));
+  const geo = new BufferGeometry();
+  geo.setAttribute("position", new BufferAttribute(positions, 3));
+  geo.setAttribute("uv", new BufferAttribute(uvs, 2));
+  geo.setIndex(new BufferAttribute(indices, 1));

-  const mat = new THREE.MeshBasicMaterial({
+  const mat = new MeshBasicMaterial({
    map: texture,
    transparent: true,
-    side: THREE.DoubleSide,
+    side: DoubleSide,
    depthTest: false,
    depthWrite: false,
  });

-  return new THREE.Mesh(geo, mat);
+  return new Mesh(geo, mat);
 }

 function disposeTextureCache(): void {
@ -184,25 +163,15 @@ function disposeTextureCache(): void {
  textureCache.clear();
 }

-function disposeScene(): void {
-  if (!scene) return;
-  while (scene.children.length) {
-    const mesh = scene.children[0] as THREE.Mesh<
-      THREE.BufferGeometry,
-      THREE.Material
-    >;
-    scene.remove(mesh);
-    mesh.geometry?.dispose();
-    if (mesh.material && "map" in mesh.material) {
-      mesh.material.map = null;
-      mesh.material.dispose();
+function buildReliefScene(icons: ReliefIcon[]): void {
+  if (!terrainGroup) return;
+  terrainGroup.traverse((obj) => {
+    if (obj instanceof Mesh) {
+      obj.geometry.dispose();
+      (obj.material as MeshBasicMaterial).dispose();
    }
-  }
-}
-
-function buildScene(icons: ReliefIcon[]): void {
-  if (!scene) return;
-  disposeScene();
+  });
+  terrainGroup.clear();

  const bySet = new Map<
    string,
@ -221,40 +190,7 @@ function buildScene(icons: ReliefIcon[]): void {
  for (const [set, setEntries] of bySet) {
    const texture = textureCache.get(set);
    if (!texture) continue;
-    scene.add(buildSetMesh(setEntries, set, texture));
-  }
-}
-
-function renderFrame(): void {
-  if (!renderer || !camera || !scene) return;
-
-  const x = -viewX / scale;
-  const y = -viewY / scale;
-  const w = graphWidth / scale;
-  const h = graphHeight / scale;
-
-  camera.left = x;
-  camera.right = x + w;
-  camera.top = y;
-  camera.bottom = y + h;
-  camera.updateProjectionMatrix();
-  renderer.render(scene, camera);
-}
-
-function drawWebGl(icons: ReliefIcon[], parentEl: HTMLElement): void {
-  const set = parentEl.getAttribute("set") || "simple";
-
-  if (ensureRenderer()) {
-    loadTexture(set).then(() => {
-      if (icons !== lastBuiltIcons || set !== lastBuiltSet) {
-        buildScene(icons);
-        lastBuiltIcons = icons;
-        lastBuiltSet = set;
-      }
-      renderFrame();
-    });
-  } else {
-    WARN && console.warn("Relief: WebGL renderer failed");
+    terrainGroup.add(buildSetMesh(setEntries, set, texture));
  }
 }

@ -274,46 +210,36 @@ window.drawRelief = (
  if (!parentEl) throw new Error("Relief: parent element not found");

  parentEl.innerHTML = "";
-  parentEl.dataset.mode = "webGL";
+  parentEl.dataset.mode = type;

  const icons = pack.relief?.length ? pack.relief : generateRelief();
  if (!icons.length) return;

-  if (type === "svg") drawSvg(icons, parentEl);
-  else drawWebGl(icons, parentEl);
+  if (type === "svg" || WebGL2LayerFramework.hasFallback) {
+    drawSvg(icons, parentEl);
+  } else {
+    const set = parentEl.getAttribute("set") || "simple";
+    loadTexture(set).then(() => {
+      if (icons !== lastBuiltIcons || set !== lastBuiltSet) {
+        buildReliefScene(icons);
+        lastBuiltIcons = icons;
+        lastBuiltSet = set;
+      }
+      WebGL2LayerFramework.requestRender();
+    });
+  }
 };

 window.undrawRelief = () => {
+  WebGL2LayerFramework.clearLayer("terrain");
+  lastBuiltIcons = null;
+  lastBuiltSet = null;
  const terrainEl = byId("terrain");
-  const mode = terrainEl?.dataset.mode || "webGL";
-  if (mode === "webGL") {
-    disposeScene();
-    disposeTextureCache();
-    if (renderer) {
-      renderer.dispose();
-      renderer = null;
-    }
-    if (glCanvas) {
-      if (glCanvas.isConnected) glCanvas.remove();
-      glCanvas = null;
-    }
-    camera = null;
-    scene = null;
-    lastBuiltIcons = null;
-    lastBuiltSet = null;
-  }
-
  if (terrainEl) terrainEl.innerHTML = "";
 };

-// re-render the current WebGL frame (called on pan/zoom); coalesced to one GPU draw per animation frame
-let rafId: number | null = null;
 window.rerenderReliefIcons = () => {
-  if (rafId !== null) cancelAnimationFrame(rafId);
-  rafId = requestAnimationFrame(() => {
-    rafId = null;
-    renderFrame();
-  });
+  WebGL2LayerFramework.requestRender();
 };

 declare global {