So I am in the midst of porting my game to windows, and then getting it onto greenlight on Steam and I have found that it runs incredibly slow (~10x slower) on a window laptop I am testing it on. The laptop isn't too bad, an i5 thinkpad win 7 4gb, and so should be able to handle a simple 2D board game without a problem.
I have narrowed the problem, causing the slowness down to a few al_set_target_bitmap() calls .
Even if the code is like this... (with no code between the calls)
al_set_target_bitmap (zbuffer_bmp) (where zbuffer is a bitmap the same size as the display)
..it slows the game down massively and I am at a loss what it might be (I have already done the "obvious" checking for memory bitmaps, and whether vsync is on etc)
If I comment out the al_set_target_bitmap the game doesn't slow down.
Can any help or have any suggestions, thanks.