Re: [pygame] Directly accessing pixel data

[JoN <jon@xxxxxxxxxxxxxxxxxx>]

I'm interested in the use of buffer objects in general, from pyopengl (so this
is more an opengl users list matter for me, forgive me).

Getting access to opengl buffer objects using ctypes is something I'm struggling
to get my head around, but there may be an even higher level way of doing it in
pygame??

Quoting Tim Ansell <mithro@xxxxxxxxxx>:

> Hello,
> 
> I'm currently using ctypes to wrap the libmng module to support MNG
> animations.
> 
> The library needs to be provided with a place to output the animation
> frames to. Currently I'm using the following method,
> 
> 1. Using ctype's c_buffer to create a file of the correct size
> 2. Use pygame.image.frombuffer pointing to the c_buffer
> 
> However it appears that frombuffer doesn't support the native pixel
> format of the screen. For example SDL is using BGRA format on my screen,
> but giving this format to frombuffer complains of "Unrecognized type of
> format".
> 
> Another way to solve the problem would be to create a surface and then
> get a pointer to the SDL pixel buffer, which I could provide the library
> with.
> 
> If I was using ctypes Pygame it looks like I could use the access the
> pointer directly using the SDL part. Is there a way I could do this with
> the older pygame? 
> 
> This is fairly important because for high speed animations the time
> required to convert to the correct format is quite high and a waste of
> resources because the library could have converted to this format as it
> was reading the data.
> 
> You can find the work so far at
> http://darcs.thousandparsec.net/darcsweb/darcsweb.cgi?r=libmng-py;a=tree
> 
> Thanks for your time.
> 
> Tim Ansell
> 
> 




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