Tileset Extruder

A tile map draws each tile from a small rectangle of one big texture. When the camera moves by a fraction of a pixel, or the map is scaled or filtered, the engine reads a hair outside that rectangle and picks up a sliver of the neighbouring tile. On screen that sliver is a thin line that flickers as you move.

Extruding puts a border around every tile that repeats the tile’s own edge pixels. Whatever the engine reads just outside the tile is now the same colour as the tile’s edge, so there is nothing to see.

• Godot: in the TileSet’s atlas settings, set Margins to the margin and Separation to the spacing shown here. The texture region size stays your tile size.
• Unity: in the Sprite Editor, slice by cell size with Offset set to the margin and Padding set to the spacing.
• Tiled: when you add the tileset, enter the same Margin and Spacing.
• Phaser: pass the margin and the spacing as the last two arguments of addTilesetImage.

Extruding fixes the lines that come from the engine. Lines that come from the art are another matter: a grass tile whose left edge does not match its right edge shows a seam however it is packed.

Click a tile and choose Tile it to see it repeated three by three, as a map would lay it. Turn on Show tile edges to see exactly where one copy ends and the next begins.