webgl: redraw when the SVG overlay finishes its async texture bake

[jackgallant]

Problem

Follow-up to #643. Even with the out-of-order race fixed, a single ROI/sulci/label toggle often still doesn't appear until you next move the brain.

SVGOverlay.update() re-bakes the overlay texture asynchronously; on completion the surface swaps it into uniforms.overlay.value and dispatches "update" on itself (mriview_surface.js:295). But addSurf only wires the surface's mix/allowTilt and the dataview's update — never the surface's own "update" to schedule(). So the texture swap lands with no redraw. The menu calls schedule() immediately on toggle, which races and usually beats the async bake, drawing the old texture; the corrected texture then sits unused until the next interaction.

Fix

surf.addEventListener("update", this.schedule.bind(this));

in addSurf, so the overlay redraws the moment its rebaked texture is committed. Together with #643's generation guard, a single toggle now deterministically settles on the current switch state. One line; node --check passes.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request adds an event listener for the 'update' event on the surface object in mriview.js to trigger a redraw when the SVG overlay asynchronously re-bakes its texture. The review feedback points out that using this.schedule.bind(this) inline creates a new function instance each time, which can lead to memory leaks as it cannot be easily removed. It is recommended to cache the bound function reference so it can be properly cleaned up later.

[gemini-code-assist]

Using this.schedule.bind(this) directly in addEventListener creates a new function instance every time addSurf is called. This prevents the event listener from being properly removed later (e.g., in rmSurf), which can lead to memory leaks.

To fix this, cache the bound function on this._schedule so the same reference can be reused and cleaned up. Note that you should also add this.surfs[i].removeEventListener("update", this._schedule); to rmSurf to ensure proper cleanup.

Suggested change

	surf.addEventListener("update", this.schedule.bind(this));
	this._schedule = this._schedule || this.schedule.bind(this);
	surf.addEventListener("update", this._schedule);