Map editor: Storing tiles as one bitmap or separate

[Aziz]

In a 2d tile map editor, after the user wants to save to map and export it, would one want to save all the tiles in one large bitmap, or to save them separately.

I was thinking that using one large bitmap was better, since you would only create on image file during runtime, rather than opening several. Also, in this case, would there be a difference in storing 30 tiles in one long string, or making it a 5x6 rectangle?

[ZeroPaladn]

Saving the whole map as one big bitmap would save memory, but I was wondering on how you would do the colission detection? If you have just one big custom map, how would the program determine which areas of the map would be ok to go on, without hardcoding it?

[Tony]

Aziz wrote:

I was thinking that using one large bitmap was better, since you would only create on image file during runtime, rather than opening several

On the other hand, you'd need to open and parse this one large bitmap just to get a single tile. I think it would depend on how you access your tile images, and what you do with them once loaded.

I don't think the arrangement (line vs rectangle) is critical, as long as you know what you are doing.

[Aziz]

That's a good point, but usually all drawing is done at one time, and each tileset is per map, so you would open image, draw map by referring to image, then close the image?

[Tony]

You could just perform a benchmark, and see which way is faster to load a sample map.

[ericfourfour]

I'd recommend having a list of tiles and a reference to each tile in the bitmap. This reference can be a number. A sample file would look like this:

file:

0 (reference number) pic.bmp (picture file) (other attributes) ... ... (repeat for other tiles) 0 0 0 0 0 0 (map) 0 1 1 1 1 0 0 0 0 0 0 0

You should also have a way for the program to tell when to change from parsing tiles to parsing a map.