Re: [pygame] Minimizing hardware-accelerated application

[Pete Shinners <pete@shinners.org>]

Heikki Salo wrote:
> Here is where my problem occurs. When iconizing the application (in HW-mode)
> the pygame crashes and says that "pygame.error: Surface was lost". I believe
> that this is the normal behaviour and when losing/gaining focus the program
> should reaquire the old mode somehow. I have managed to use ACTIVEEVENT and
> "pygame.display.toggle_fullscreen()" so that it is ok to iconize the
> application, but when toggling back to fullscreen the program crashes with
> that surface lost-error. What is the "normal" thing to do in order to
> prevent those crashes? Any example would be nice.
the "lost surface" is the achilles heel of directx. directx will 
destroy your surfaces automatically and not tell you about it until 
later you try to actually use the surface (Thanks MS!)

what your app will need is a way to restore images. for simple 
programs this might not be too hard, but becomes a challenge once you 
start having programmtically created surfaces and more.

what you likely need is a small class to hold a surface and some 
functions for rebuilding the surface. this will require building a bit 
more framework for your game.

class ImageSurface:
    def __init__(self, filename):
        self.filename = filename
        self.s = None
        self.restore()
    def restore(self):
        self.s = pygame.image.load(self.filename).convert()

you could make these classes for different types of images, like alpha 
or colorkeyed surfaces also. now when drawing, if the surface is lost 
you are still ok.

def drawsurface(dst, src, pos):
    try:
        dst.blit(src.s, pos)
    except pygame.error: #lost surface!
        src.restore()
        dst.blit(src.s, pos)


as for the "toggle full screen", the function really only works on 
linux. you can always call pygame.display.set_mode() a second time and 
it will close the original and open a new window.