Replaced refetch-based updates with continuous per-frame redraw.
The corridor now tracks the camera's continuous world position
(floating point, not floored to a tile) so the tile content
scrolls smoothly underneath the camera. No more 'jump by 1 tile'
at every refetch boundary.
Tradeoff: every frame draws ~65 images and does one texImage2D
upload. Browser caches the Image elements, so the cost is mainly
compositing + upload (~5MB at 6400x1280). Should still hit 30+ fps.
This is closer to how real flight sims work: the world content
scrolls continuously, not in tile-size jumps.
Richard Zink
4f8fd4b62a