[PyOpenGL-Users] [ pyopengl-Feature Requests-1311265 ] glReadPixels enhancement request

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Feature Requests item #1311265, was opened at 2005-10-02 19:00
Message generated for change (Comment added) made by mcfletch
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Stuart Woolford (swoolford)
Assigned to: Nobody/Anonymous (nobody)
Summary: glReadPixels enhancement request

Initial Comment:
When using glReadPixels in combinations with pixel buffer 
objects 
(PBOs) the last (C) argument is no longer the address of 
memory to 
move the data to, but an offset from the currently defined buffer 
object base. 
 
As a trivial example it is connon to use: 
glReadPixels(0,0,640,480,GL_BGRA,GL_UNSIGNED_BYTE,0) 
Which causes the data to be copied to the base (0 offset) of the 
currently defined PBO. 
Of course, in pyOpengl this does not seem doable, as the 
buffers are 
handled internally, and the last argument is not exposed. 
Is it possible that we could have new versions of the affected 
calls 
exposed that do take the last argument? 
Perhaps a glReadPixelsB (for buffer) or something like that? 
(glWritePixels has the same limitation). 
 
PBOs are a very important feature for using openGL in image 
processing, so this would be a very useful addition. 
It would also allow glReadPixels to be used from python in 
situations 
where the overhead of the double data copy currently required for 
the 
(much easier to use) current implementation is too much when 
moving 
through bounce buffers. 

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>Comment By: Mike C. Fletcher (mcfletch)
Date: 2009-07-19 00:15

Message:
I've just added code to bzr head to support passing in the array argument
to glReadPixels, but haven't found glWritePixels to alter that.

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You can respond by visiting: 
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