A tileset is an image file which contains several graphics used by tiles.
Tilesets are saved in, relative to the CS2D dir, /gfx/tiles.
When loading a tileset into a map, CS2D assigns each tile a tile ID (or sometimes called "frame"). Tile IDs range from 0 to 255. The topleftmost 32×32 area of the image is considered tile #0, then it looks on the area 32 pixels to the right from it; this is tile #1 and so on. If CS2D finishes the row of tiles, it looks for the next row and looks on the leftmost 32×32 pixel area of that row. CS2D repeats this until the whole tileset has been loaded.
- When using as a 24-Bit Bitmap, all magenta (Red: 255, Green: 0, Blue: 255) pixels are rendered transparent by CS2D, meaning, the map background becomes visible instead. For example, tile #0 of dust.bmp (tileset of de_dust) becomes entirely transparent. However, semi-transparent pixels or tiles are not possible with a 24-Bit Bitmap.
- When using a Portable Network Graphic instead, CS2D uses the semi-transparency of the image, so there could be tiles which shows half the tile, half the background, for example. In this case, magenta pixels are rendered magenta and not transparent.
- As a convention, in most tilesets the tile #0 is entirely transparent for the background.
- A tileset image must be either a 24-Bit Bitmap (BMP) or a Portable Networks Grahpic (PNG).
- PNG is probably the better choice because it has two major advantages:
- way smaller file size than BMP (important for online play)
- semi-transparency (important for, uhhm, fancy graphics)
- must have a width and a height which are both divisible by 32.
- should have no more than 256 tiles. (tiles after #255 are ignored)
- must be either in the 24-Bit Bitmap (BMP) or in the Portable Networks Graphic (PNG) format.