⚡ Bolt: Optimize WebGL loop to reduce GC and layout thrashing #54

2026-02-04T01:39:14Z

ragusa-it commented

2026-02-04 01:39:14 +00:00

(Migrated from github.com)

⚡ Bolt: Optimize WebGL loop to reduce GC and layout thrashing

💡 What:

Replaced useRef holding immutable objects/arrays ({x,y}, [x,y]) with mutable objects for pointerPosRef and mouseTargetRef.
Removed a fallback canvas.getBoundingClientRect() call inside the requestAnimationFrame loop that was causing synchronous layout thrashing when rectRef wasn't immediately available.

🎯 Why:

The previous implementation created new object instances on every mouse move and every frame, causing unnecessary Garbage Collection pressure.
The synchronous layout read in the animation loop (even as a fallback) is a severe performance anti-pattern that can cause dropped frames, especially during initialization or resizing.

📊 Impact:

Reduces GC overhead significantly during mouse interaction.
Eliminates potential forced reflows during the animation loop.

🔬 Measurement:

Verified code logic ensures coordinate updates are handled safely without fallback layout reads.
Existing tests (logic-wise) are respected, specifically the requirement to avoid expensive DOM reads in event handlers.

PR created automatically by Jules for task 6571928292931476466 started by @ragusa-it

⚡ Bolt: Optimize WebGL loop to reduce GC and layout thrashing 💡 What: - Replaced `useRef` holding immutable objects/arrays (`{x,y}`, `[x,y]`) with mutable objects for `pointerPosRef` and `mouseTargetRef`. - Removed a fallback `canvas.getBoundingClientRect()` call inside the `requestAnimationFrame` loop that was causing synchronous layout thrashing when `rectRef` wasn't immediately available. 🎯 Why: - The previous implementation created new object instances on every mouse move and every frame, causing unnecessary Garbage Collection pressure. - The synchronous layout read in the animation loop (even as a fallback) is a severe performance anti-pattern that can cause dropped frames, especially during initialization or resizing. 📊 Impact: - Reduces GC overhead significantly during mouse interaction. - Eliminates potential forced reflows during the animation loop. 🔬 Measurement: - Verified code logic ensures coordinate updates are handled safely without fallback layout reads. - Existing tests (logic-wise) are respected, specifically the requirement to avoid expensive DOM reads in event handlers. --- *PR created automatically by Jules for task [6571928292931476466](https://jules.google.com/task/6571928292931476466) started by @ragusa-it*

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google-labs-jules[bot] commented

2026-02-04 01:39:15 +00:00

(Migrated from github.com)

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copilot-pull-request-reviewer[bot] (Migrated from github.com) reviewed 2026-02-04 01:41:57 +00:00

copilot-pull-request-reviewer[bot] (Migrated from github.com) left a comment

Pull request overview

This PR optimizes the WebGL animation loop in the GradientBlinds component to improve performance by reducing garbage collection pressure and eliminating layout thrashing. The changes replace immutable object allocations with mutable object updates and remove synchronous getBoundingClientRect() calls from the animation loop.

Changes:

Converted mouseTargetRef from array [x, y] to object {x, y} and updated all references to use property access
Changed pointerPosRef from nullable object to object with active boolean flag to track pointer state without creating new objects
Removed getBoundingClientRect() fallback calls from both the pointer event handler and the animation loop to prevent layout thrashing

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/components/effects/GradientBlinds.tsx	Refactored pointer tracking refs to use mutable objects and removed synchronous layout reads from the animation loop
.jules/bolt.md	Added documentation about WebGL layout thrashing learnings and best practices

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## Pull request overview This PR optimizes the WebGL animation loop in the GradientBlinds component to improve performance by reducing garbage collection pressure and eliminating layout thrashing. The changes replace immutable object allocations with mutable object updates and remove synchronous `getBoundingClientRect()` calls from the animation loop. **Changes:** - Converted `mouseTargetRef` from array `[x, y]` to object `{x, y}` and updated all references to use property access - Changed `pointerPosRef` from nullable object to object with `active` boolean flag to track pointer state without creating new objects - Removed `getBoundingClientRect()` fallback calls from both the pointer event handler and the animation loop to prevent layout thrashing ### Reviewed changes Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment. | File | Description | | ---- | ----------- | | src/components/effects/GradientBlinds.tsx | Refactored pointer tracking refs to use mutable objects and removed synchronous layout reads from the animation loop | | .jules/bolt.md | Added documentation about WebGL layout thrashing learnings and best practices | --- 💡 <a href="/ragusa-it/ragusaitweb/new/main/.github/instructions?filename=*.instructions.md" class="Link--inTextBlock" target="_blank" rel="noopener noreferrer">Add Copilot custom instructions</a> for smarter, more guided reviews. <a href="https://docs.github.com/en/copilot/customizing-copilot/adding-repository-custom-instructions-for-github-copilot" class="Link--inTextBlock" target="_blank" rel="noopener noreferrer">Learn how to get started</a>.

src/components/effects/GradientBlinds.tsx

						
				@@ -373,11 +370,12 @@ void main() {

				        if (factor > 1) factor = 1;

				        const target = mouseTargetRef.current;

				        const cur = uniforms.iMouse.value;

copilot-pull-request-reviewer[bot] (Migrated from github.com) commented

2026-02-04 01:41:57 +00:00

The comment on line 332 states "Fallback: do nothing if rect is not ready yet to avoid sync layout thrashing", but the code actually does write to mouseTargetRef.current with the values of x and y, which are initialized to 0 on line 322. If rectRef.current is falsy, the coordinates will be set to (0, 0).

This differs from the desktop path (line 349), which only updates mouseTargetRef.current when both pointerPosRef.current.active AND rectRef.current are truthy. For consistency and to truly "do nothing" as the comment suggests, the mobile path should also guard the writes to mouseTargetRef.current with a check for rectRef.current.

The comment on line 332 states "Fallback: do nothing if rect is not ready yet to avoid sync layout thrashing", but the code actually does write to `mouseTargetRef.current` with the values of `x` and `y`, which are initialized to 0 on line 322. If `rectRef.current` is falsy, the coordinates will be set to (0, 0). This differs from the desktop path (line 349), which only updates `mouseTargetRef.current` when both `pointerPosRef.current.active` AND `rectRef.current` are truthy. For consistency and to truly "do nothing" as the comment suggests, the mobile path should also guard the writes to `mouseTargetRef.current` with a check for `rectRef.current`.

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Reference: ragusa-it/ragusaitweb#54