Add support for virtual filesystems.

[holywyvern]

I am attempting to integrate physfs with this library, and it has some troubles with nested resources.
In other words, when I load a map with a tsx file included, because the library uses fopen instead of a custom handler, you can't use it.

Is there a way to integrate a virtual filesystem, like adding some callbacks like "tmx_load_file_fn" or "tmx_load_tileset_fn" ?

[edin-m]

Could tmx_load_buffer() be of use here? Load from physfs to char* buffer then use this func to parse.

[mupfdev]

This would be very helpful to use libTMX on Android. I created a fork especially for this purpose: https://github.com/mupfelofen-de/tmx-android

A way to register respective callback functions would probably a quite elegant solution. Haven't thought about that.

[holywyvern]

Could tmx_load_buffer() be of use here? Load from physfs to char* buffer then use this func to parse.

Oh it almost works, it works if you embed the resources on the tilemap, but if you want to keep them separate, tmx loads the assets individually, so load buffer will load the first one just fine, but any dependency will try to be loaded using the standard file system.

[holywyvern]

This would be very helpful to use libTMX on Android. I created a fork especially for this purpose: https://github.com/mupfelofen-de/tmx-android

A way to register respective callback functions would probably a quite elegant solution. Haven't thought about that.

I did end up making a fork with a virtual file system:
https://github.com/holywyvern/tmx