Re: [pygame] Re: Accessing opengl surface as a numpy array

[Nicolas <nblouveton@xxxxxxxxx>]

2010/11/12 Ian Mallett <geometrian@xxxxxxxxx>:
> On Fri, Nov 12, 2010 at 1:25 PM, nbl <nblouveton@xxxxxxxxx> wrote:
>>
>> In fact, I work on a software implementing some processes on a
>> "visual" stream.
>>
>> I don't need all frames' pixels as long as frames are spatially
>> sampled before all.
>
> Not sure what you mean exactly here.  If you're doing mostly software
> operations, try to keep your data in software (i.e., only use OpenGL for
> rendering the output, or don't use it at all).  If you're doing heavy
> graphics work, do it on the GPU.  If you're really stuck, do the work on the
> GPU with a shader (although that might be overkill for your purposes; I
> still don't understand them entirely).

I don't work on display operations themselves. I work on a library
which could be able to handle different kind of video input and
applying mapping operations on it. The first operation is to reduce
visual information with a spatial sampling. Thus, I don't need to
access all pixels, actually a very small fraction of them.

With surfarray, I just access relevant pixels but... since I don't
find in openGL doc a method providing an access to a specific pixel, I
will try with glReadPixels and reading pixels as 1-pixel-sized frames
at a time.

Cheers,
Nicolas