In any way that works for you... However, I have seen bit maps (*.bmp) like fiiles in several formats. A monochrome, greyscale, true color, and with an alpha value (ARGB or is that ABGR), meaning...
Code:
11111111
10000001
10011001
10011001
10011001
10011001
10000001
11111111
in a monochrome bitmap style, each bit, either a zero or a one, denotes where a player can walk/move, or it could mean something else...
Same can be said for a 256 greyscale image where each byte, pixel, contains some sort of meaning as each byte can be a value from 0 to 255. So this could be a height map or a movement cost map, or... well let your imagination run wild with that...
Then of course, the bitmap type of file we may be more used to where each pixel has an RGB value and each byte (r,g,b) for each pixel can mean something.
Of course after that, there is the alpha channel with each pixel.
Now, these don't actually have to be *.bmp files (or *.jpg, *.png), but if you are going to let your users define game envionments, terrain, obstacles, etc. it is one way to do so. Another way, like the game of Decent, an older game, which was in 3d. They used a common 3d environment formated file that I believe most users used Autocad to design levels with.
Now, these file formats can be of your own design, or you can use an established file format and just used it for your own purposes...
Good Luck
Artificial Intelligence...
Linear Mode
