Crash BASIC 1.48.1 Release Notes

written by Crash-tan

THE "MIND THE GAP" FIX

Tile-based games could show thin seams between tiles — a one-pixel line flickering along tile edges — on some hardware, most visibly on Apple TV, at certain scroll positions. If your platformer or top-down map looked crisp on your computer but grew hairline gaps on the big screen, this is that.

What was happening

For every pixel on screen, the tilemap shader works out which tile that pixel belongs to and where inside the tile to read from. A couple of those calculations were done separately, and the tile artwork was sampled right on the boundary between one tile's pixels and the next. On most graphics chips the rounding lined up and everything stayed seamless; on others — the Apple TV's among them — it rounded the other way, and a pixel at a tile's edge would grab a sliver of the neighboring tile. That's the seam. It only appeared at the scroll offsets that landed pixels exactly on those edges, which is why it flickered in and out as you moved.

The fix

The shader now works out the tile and the spot within it from a single calculation, so they can't disagree, and reads each tile pixel from its center instead of its edge, so rounding can't spill into the next tile. Tiles stay seamless on every platform, at any scroll position and any resolution — nothing to turn on. Because the fix is in the shared renderer, it covers desktop, web, mobile, and the Windows/Xbox path all at once.