Re: [pygame] Speed up image.tostring with OpenGL ?

[Alexandre Quessy <alexandre@xxxxxxxxxx>]

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Hello everyone !

René Dudfield wrote:
> Hi,
> 
> try using surfarray.  To avoid converting the data to a python string.
>  pyopengl supports numpy arrays to do this.
> 

This is very nice !
So far, I followed Brian's tip, and changed from RGBX to RGB. It is
already faster.

> 
> # something like this... untested.
> w,h = surf.get_size()
> data = pygame.surfarray.pixels2d(surf)
> texture = glGenTextures(1)
> glBindTexture(GL_TEXTURE_2D, texture)
> glPixelStorei(GL_UNPACK_ALIGNMENT,1)
> glTexImage2D(GL_TEXTURE_2D, 0, 3, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, data)
> # ... etc...
> 

Since I am reading from the pygame.camera.Camera, the image has a 24 bit
depth. This format is the only one that is not supported by
surfarray.pixels2d. Can I change the format that the Camera gives me ?

> Also to speed up image loading/decoding...
>     import pygame.threads
>     pygame.threads.init(8)
>     surfs = pygame.threads.tmap(pygame.image.load, your_images)
> 
> Another thing to do is to make sure you are reusing textures (if
> possible).  Since allocating a new texture each time can be slow, so
> if you application allows it, reuse textures.
> 

I am much used to that kind of texture reusage. (that's one of the
reasons why I am addicted to OpenGL, even when it would be better not to
use it...) In this case, though, I am reading live from the camera, plus
reading though a very long list of surfaces, often more than the number
of textures I can store on the graphics card.

Thanks a lot for helping !

alex

> 
> 
> cheers,
> 
> 
> On Mon, Jan 4, 2010 at 4:06 AM, Alexandre Quessy <alexandre@xxxxxxxxxx> wrote:
>> Hello Pygame users and developers !
>>
>> Is there a way I can speed up the transfert from a surface to an
>> OpenGL texture ? Right now, I use the pygame.image.tostring function,
>> but it seems like converting the pixels to a Python str creates a
>> serious bottle neck in my stop motion application...
>>
>> I think that it should either be implemented directly in Pygame, (best
>> option) or done using something like ctypes in my application. If none
>> of these option is not easy enough, I am thinking about switching to
>> Gstreamer+GTK with the GdkPixBuf, instead of Pygame surfaces. An other
>> option would be to rewrite the whole application in C++...
>>
>> Any suggestion to fix this in a way that is not too long ?
>> My frame rate drops to 4 FPS when there are more than a few surfaces in my list.
>> Please try Toonloop to test this out. It works well on Linux. If
>> someone get it to work on Mac or Windows, I would need hints for
>> packaging it for those OS too. I convert the surfaces to OpenGL
>> texture in texture_from_image from the file
>> http://bitbucket.org/aalex/toonloop1/src/tip/toon/draw.py on what is
>> currently the line 42.
>> --
>> Alexandre Quessy
>> http://alexandre.quessy.net/
>>
> 
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