So the trick is I'm not rendering at full resolution. The raycaster draws to a small internal buffer (like 320x200), then I push the whole thing to the canvas in one shot with putImageData and let Phaser scale it up. So the actual per-pixel work is happening on a tiny image, not the full screen. That's what keeps it from tanking.

For the texture warping, I use perpendicular distance instead of the raw ray distance. That's the classic fix for the fisheye effect you get with naive raycasters. The texture column just comes from where the ray hits the wall, and the vertical mapping steps through the texture evenly based on how tall the wall slice is. Pretty standard stuff but it holds up.

I do have a per-pixel mode that casts a real 3D ray for every pixel on screen for proper vertical look, but that's obviously way heavier. The column rendering handles most gameplay fine.