Re: [pygame] intermittant fails of unit test pixelarray_test.PixelArrayTest with Python 2.4

["René Dudfield" <renesd@xxxxxxxxx>]

are all the warnings fixed for that code?  Maybe that'd give a clue?

setup.py -warnings


Have you tried a different video driver?  Maybe that'd change things.



On Wed, Feb 27, 2008 at 7:07 AM, Lenard Lindstrom <len-l@xxxxxxxxx> wrote:
> Brian Fisher wrote:
>  > It seems to me once the failure is reliably repeatable it should be
>  > fairly straightforward to debug, right?
>  >
>  >
>  I wish. :-)
>
>
>  > ...but I'm a bit confused, looking at the test that is failing, I'm
>  > not sure how that could be considered a repeatable test...
>  >
>  >
>  The fails are not 100%, but nearly so. And it differs between Pythons
>  2.4 and 2.5.
>
>
>  > with 8 bpp, don't you have to set a palette? the SDL docs
>  > SDL_CreateRGBSurface say: "If depth is 8 bits an empty palette is
>  > allocated for the surface" - and set_at is calling SDL_MapRGBA which
>  > will map the (255, 255, 255) tuple to the closest index in the
>  > palette. Also, the "in" operator on PixelArray objects always works on
>  > palette indices for 8 bit (if given a color tuple it will call
>  > SDL_MapRGBA to map it to a palette index as well). So isn't the exact
>  > behavior dependent on the values of an "empty palette"?
>  >
>  >
>  It could be using a default device palette on Windows. Using
>  get_palette, I compared the palettes of the test surface for both a pass
>  and fail. They were identical.
>
>
>  > So given that the palette is undefined, why shouldn't (255,255,255)
>  > map to index 255 (0x000000ff)? And why shouldn't 0x000000ff exist as a
>  > member of the array in that case? likewise why shouldn't (0,0,0) map
>  > to index 255?
>  >
>  > So Lenard, when the test fails what does sf.map_rgb((255,255,255))
>  > return? does it return 255? how about sf.map_rgb((0,0,0))?
>  >
>  For both pass and fail I get (0,0,0) --> 0,  (255,255,255) --> 127. But
>  sf.unmap_rgb(0x000000ff) is (255,255,255), the same as sf.get_at((8,8)).
>  So the test should always fail. The question now becomes, why does it pass?
>
>  To check if screen depth has anything to do with this I set my display
>  to 32 bit and rebooted. The test failed for Python 2.4 and passed for
>  2.5. But True Color on my system has no alpha channel. Maybe alpha
>  affects the test on XP.
>
>  This behavior is consistent with accessing a memory location whose value
>  is undefined. Just adding a "print 'x'," at the start of test_contains
>  was enough to make the fails nearly 100% for Python 2.4. I will keep
>  looking.
>
>  --
>
>
> Lenard Lindstrom
>  <len-l@xxxxxxxxx>
>
>