Hi, I kinda of like the good ol'' top-down shooters and side-view platform games that have tile-based maps. As such, that''s the kind of thing I''m interested in developing. What I''m wondering, with all the 3d games these days, is it still possible to find good tile artists? Tiles seem to be a pretty difficult thing to make, taking both artistic talent and technical know-how. Seemless tiles that together look as though there are no tiles. [Btw, I''m talking tiles here, not just textures...] Thanks, Nathan. nathany.com

Hi, I work as an artist for a commercial software entertainment company here in the UK, and seeing as I''ve a spare half hour, here goes:

Tilesets evolved due to a lack of GRAPHICS RAM in early home computers, 8 and 16 bit consoles, in order to create the appearance of a vast sprawling landscape (amongst other things), with a very limited number of characters.

Graphics ram is responsible for storing :

Characters
Traditionally, 8 bit machines were limited to 256 ''characters'', of 8x8 pixels. A character is essentially a blank space, 8x8 pixels in size. However 16 bit machines and up, are capable of storing characters of 8x8 pixels, upto 64x64 pixels (typically 16x16 pixels), simply because their architecture allows it.

Tiles
A tile (also sometimes called a block), is not necessarily of a fixed size, however, machine limitations and architecture mean that these are generally fixed at either 16x16 pixels (meaning it will contain 4, 8x8 pixel characters) in the case of an 8 bit machine, and many varying combinations on 16 bit machines, including 16x32 pixels, or 32x32 pixels etc made up of either 8, or 16 pixel characters .. Still with me ?

Tile size is determined by the project programmer and artists to an optimum number, dependant on many, many factors (gameplay style, graphical style, animating backgrounds? do we have ''draw'' to the map ... etc etc etc).

Typically you would have 128, 256, 512 etc etc tiles, made up from a common set of 256 characters. The reason for this is about to become as clear, as mud ... lol

Map
Maps use a HUGE amount of memory, even in todays handheld consoles (eg. Gameboy Color), and memory quite simply, costs money. Therefore, tiles are beneficial in that they are used to reduce the amount of data you have to store both in graphics ram, and on a cartridge.

For example, imagine a mini-map of 8x8 characters. If we stored the map as below, it would require 64 bytes of memory (1 byte per character) of map.

12345678
12345678
12345678
12345678
12345678
12345678
12345678
12345678

However, if we use a tileset of 2x2, we only store:

ABCD
ABCD
ABCD
ABCD

where, for example, A is made up of the characters:

character 1 = top left character (tlc)
character 2 = top right character (trc)
character 1 = bottom left character (blc)
character 2 = bottom right character (brc)

Thereby reducing the amount of memory required to store the map by a quarter. Now considering that some games may use, for example, 32 maps of 500 tiles by 500 tiles, you can hopefully see the advantages.

Now, we also have to store the tile definitions, which tells us which characters are stored in which tile and would take the format of the last example above.

tile number, tlc, trc, blc, brc

The utility that I use to draw tilesets is ProMotion (which does rather usefully save .bmp format), alternatively you can use Electronic arts Dpaint Animator, however you will have to study the format of the graphics file in order to extract the raw data, and any color data you might need, and that''s a very, very long story

As for creating TILES, I''m willing to knock together a few .bmp sheets of ''work'' for anyones perusal, but now, alas, it is late. TIME FOR BED!

/o)