Restore on webgl context loss

[VariableVince]

Description:

When WebGL context is lost, restore context and all elements.

In GameView, handle potentially transient undefined states during context loss gracefully.

Test with chrome://gpucrash from another tab, then return to the game tab to see it being restored
(This fake gpucrash only works once sometimes. Because the second time the browser might reject the tab it thinks caused the gpu crash, access to hardware acceleration. And after even more tries even disables it browser-wide. A browser restart resets it in that case.)

Please complete the following:

• I have added screenshots for all UI updates
• I process any text displayed to the user through translateText() and I've added it to the en.json file
• I have added relevant tests to the test directory
• I confirm I have thoroughly tested these changes and take full responsibility for any bugs introduced

Please put your Discord username so you can be contacted if a bug or regression is found:

tryout33

[coderabbitai]

Walkthrough

GameView defers renderer init and emits contextrestored. WebGLFrameBuilder gains clearCaches(). ClientGameRunner listens for contextrestored and performs a full GPU-state reupload (terrain, tiles, trails, structures, railroad, units). Territory/Trail dirty-row updates are guarded while full uploads are pending.

Changes

WebGL Context Recovery + Render-pass updates

Layer / File(s)	Summary
Context restored event contract src/client/render/gl/Events.ts	contextrestored event added to GameViewEventMap with payload { type: "restored" }.
GameView nullable renderer and recovery infrastructure src/client/render/gl/GameView.ts	Make GPURenderer nullable, add initRenderer() for lazy init, install WebGL context lost/restored listeners, cache radial icons and frame callbacks, convert renderer facades to optional chaining, and remove listeners on dispose.
WebGLFrameBuilder cache clearing src/client/WebGLFrameBuilder.ts	Add clearCaches() to reset knownSmallIDs and localPlayerSmallID so next update() re-syncs players.
Context restoration orchestration in client runner src/client/ClientGameRunner.ts	mountWebGLFrameLoop keeps a persistent WebGLFrameBuilder, registers contextrestored handler that clears caches, regenerates terrain refs/bytes for all tiles, re-uploads tile/trail/frameData (including units as Map<number, UnitState>), forces structure/railroad uploads, and flushes via builder.update(gameView); returns { builder }.
Territory & Trail dirty-row guards src/client/render/gl/passes/TerritoryPass.ts, src/client/render/gl/passes/TrailPass.ts	When a full upload is pending, drainDripBucket/flushAllDripBuckets and applyLiveDelta avoid recomputing or narrowing dirtyRowMin/dirtyRowMax, preserving full-upload semantics.

Sequence Diagram

sequenceDiagram
  participant WebGL as WebGL Context
  participant GameView
  participant Client as ClientGameRunner
  participant FrameBuilder as WebGLFrameBuilder
  participant GPURenderer
  WebGL->>GameView: contextlost
  GameView->>GPURenderer: dispose() and set renderer = null
  GameView->>Client: emit "contextrestored" { type: "restored" }
  Client->>FrameBuilder: clearCaches()
  Client->>FrameBuilder: regenerate terrain refs/bytes & reupload frameData (tiles/trails/units)
  FrameBuilder->>GameView: update(gameView)
  GameView->>GPURenderer: initRenderer() (lazy)

Loading

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• openfrontio/OpenFrontIO#3973: Related changes to drip-bucket staging and territory/trail upload behavior.

Suggested reviewers

• evanpelle

Poem

When contexts drop and pixels sleep,
Builders wake and caches sweep,
Terrain reborn, the tiles align,
Renderer wakes — frames stream fine. 🎮✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main objective: restoring WebGL context after loss, which is the primary focus of all code changes in the changeset.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The pull request description clearly describes implementing WebGL context loss restoration with specific test instructions and implementation details aligned with the changeset.

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/client/render/gl/GameView.ts`:
- Around line 255-256: The updatePalette method currently only calls
this.renderer.updatePalette(paletteData) and neglects to update the cached
palette used during restore; modify updatePalette (in class GameView) to also
store a copy of the incoming palette into this.paletteData (e.g.,
this.paletteData = new Float32Array(paletteData) or similar) so the
restore/rebuild path uses the runtime-updated palette; keep the existing
renderer.updatePalette call intact.
- Around line 74-105: The new GPURenderer is created with a default camera after
a context loss because we never save/reapply the previous camera; modify the
class to capture the current camera into a cachedCameraState before disposing
(in onContextLost — call renderer.getCameraState() or read renderer.camera) and
then, inside initRenderer (or immediately after creating the new GPURenderer),
reapply that state via renderer.setCameraState(cachedCameraState) (or assign
renderer.camera = cachedCameraState) so the view is restored; ensure
onContextRestored still calls initRenderer and that cachedCameraState is
cleared/validated as needed.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 07c6744a-4b13-4e52-aeeb-066be4871586

📥 Commits

Reviewing files that changed from the base of the PR and between 15ac42b and b6750bc.

📒 Files selected for processing (5)

• src/client/ClientGameRunner.ts
• src/client/WebGLFrameBuilder.ts
• src/client/render/gl/Events.ts
• src/client/render/gl/GameView.ts
• src/client/render/gl/passes/TerritoryPass.ts

[evanpelle]

sorry about the conflicts :(

[VariableVince]

sorry about the conflicts :(

yeah fu ;) but have resolved them and made it work with the bucket-changes. Please review again when possible