Interesting.

Whenever a resize is created, it destroys and recreates a new display. Since all bitmaps are attached to the display, you'll need to reload and/or recreate any bitmaps.

My guess is that a note should be added to the documentation.

I think you might be right. This particular discussion is about the display losing focus but I believe the principal is the same:

I don't see how an ALLEGRO_BITMAP can be created and then all the pointers that previously referenced it are now able to point to the new bitmap.

Can you try if it also happens with a TTF font? It definitely sounds like a bug in Allegro to me.

As a test, I called al_acknowledge_resize even when the window had not actually been resized and when it was in windowed mode, and it killed my font. I didn't have any other bitmaps yet so I didn't notice anything (the rest is draw via primitives calls).

This may be partially my fault, because if I wrap the al_acknowledge_resize call with a condition (for example on a key down event), it works. I actually was testing whether or not I really needed to listen for resize events and call resize -- if I could just call it every loop, since on every loop I already call al_get_display_width and al_get_display_height and set a transform to scale the "fixed" game to the window. I should try legitimately listening for the resize event and only calling ack then to see if there are any problems.

I also tested this with a normal load_bitmap call loading a JPG and saw the same results. Interestingly in one test Windows 10 said my NVIDIA windows kernel driver crashed and it restarted it.

I'm willing to try any version of Allegro but I'm working from my jalleg library and trying to call every module, so I don't have any C compiler, plus I've heard the dependencies build on Windows is quite involved. I didn't see any 5.2.1 snapshot on GNA.

I am using the 64-bit Windows prebuilt binaries linked from the site: http://download.gna.org/allegro/allegro-bin/5.2.0/, so based on the name it's MinGW.

Hi SiegeLord, I tried out the new DLL, there is no change from my current Allegro (which reports as 5.2.0.1, while yours reports as 5.2.1.0). However, I will say that when I implement the resize properly, I can't reproduce it, by that I mean:

al_set_new_display_flags(ALLEGRO_RESIZABLE);
mainDisplay = al_create_display(640, 480);
//... in event loop:
if (event.type == ALLEGRO_EVENT_DISPLAY_RESIZE) {
  al_acknowledge_resize(mainDisplay);
}

instead of just calling al_acknowledge_resize constantly. Since it's really not that hard to add to my loop, I am doing it that way. But it would be nice to know if formally I am guaranteed not to lose bitmaps, etc., or whether or not I need to know to reload them.