People seem to plan them all the time, but still no-one ever seems to actually use them, so I wonder - could an RPG/tilemap (i.e. a library sophisticated enough for RPG development but also simple enough for regular 2d sidescrollers) library addon for Allegro ever succeed with you people?

Well, here's my plan for mine; there's a flag in the file format that specifies whether that particular file uses bitmasks or just solid/walkable, whether it has animations, whether it's got its own tileset (it could use an external one provided by the user), etc. Since I want to be able to use it for a variety of stuff, customization is important to me too Perhaps I'll add support for multiple tilemap layers like the KQ editor and Mappy do (right now, you need multiple tilemaps). Maybe I should look at the Mappy file format for ideas ...

> Different tile sizes
Not at the moment (32x32 is hardcoded) but it should be easy to change.

> Section layers (layers smaller than entire map)
I don't see why not. It doesn't support multiple layers at ALL right now, but if it did, it shouldn't be hard. My level editor uses tilemaps of different sizes at the same time, and lets you move them in relation to each other. Not hard.

> Parallax layers (tiled as well as pictures)
Parallax pictures? Anyway, my tilemaps have "speed", so a map with 0.5 speed will move half as fast as one at 1.0 speed (the default). I'm doing that now in the game

> Different tile sizes in each layer
Didn't think of that, but no sweat ...

> Different tilesets in each layer
Doing that now in the game Good ideas; I'm logging these ...

Right; I've thought about that too. I guess it could be a 1x1 map with 640x480 tiles

I also check for hardware acceleration for blitted and masked tiles, plus I've got transparency, and I have plans for animation.

Another thing; If you're going to make a general map editor, make sure to let people write their own export routines for their own map formats; either through plugins or some other system. It's not always fun being stuck with a file format you don't like ...

There's a difference between making the all-purpose map editor and making a map editor (among other tools) for an RPG. The all-purpose map editor shouldn't impose much on the user that can't be changed. I would argue that the type of map itself (hex, square tile, isometric) should be editable and configurable via plugins. The user should be able to hand, and edit, application specific data off of a tile position or a tile-type via plugins. And, of course, the export of data should happen via plugins as well.

Now, a tilemap for use by an already built RPG engine is a different story. Since this is a full RPG engine we're talking about here, the user won't be quibbling over file-formats; no exporter plugin. However, adding additional data to the file format is important. As such, the user should have plugins that add data to tiles and tile positions, and this data will be automatically loaded by the game engine and made avalaible for immediate use in code/scripts.

As for the thread's main question, such a library could catch on, but probably not for Allegro users. Regardless of the flexibility of the system, most Allegro users tend to be far too unwilling to look at, let alone use, any moderately high-level library. And such an engine would provide the game loop and so forth, so coding for it would be a matter of deriving new classes and writing new scripts for those classes. I doubt many Allegro programmers are willing to use an engine that has that much of the code written for them.

Also, in order for such an engine to be useable, it must have excellent documentation. Since it is an application framework that controls most of the game internally, it is important for the system's behavior to input/function calls to be very precisely documented.

Korval: Yup, I know - I sort of got the impression that 23 wanted it to be more all-purpose than strictly RPG (his current game isn't even an RPG ...).

I'm not sure if this is worth the effort, actually.
If you do it, you should take it one step further, add lua and make it a higher level game engine. Not just a tile engine.

The reason is that the engine will be pretty complicated. So newbs won't understand it, and the vets will code their own engine in the time needed to learn / customize the tile engine.

If you're talking to me, no. Well, you could, but I figure assigning a "script ID value" to each tile might be more flexible, in case you want the player to find a certian book in a library. Suddenly all bookcase tiles can't do the same thing, right? OTOH, that callback function I mentioned before could also take the coordinates of the tile, which could be used for specific instances like that. And of course not all floor tiles can trigger events, though some will. Maybe instead of having a zone layer, the tilemap object could keep a hash table or something of the zones. Beats keeping a 60x60 array for 3 script triggers

That's what KQ has, I think. Script ID value == zone number, doesn't it?

Ugh ... it would be a NIGHTMARE to design maps in such a way, IMHO.

Right, which makes the XML bit sort of moot ... I doubt the use it would have, even as an intermediary for conversion.

Korval: I totally agree with you.

XML is just hype.