Re: [pygame] Directly accessing pixel data

[Alex Holkner <aholkner@xxxxxxxxxxxxxx>]

JoN wrote:

> 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??
>  
You cannot get random access to texture buffer objects.  Use 
glTexImage2D (or variant) to supply the initial data, and 
glTexSubImage2D to update it.  ctypes is very flexible with what you can 
pass as a 'void *' to these functions, for example, a string, list, 
ctypes array will all work.
You can read back pixel data from a texture or buffer using 
glReadPixels, but this is not a common operation.

Vertex buffer objects can be mapped into system memory: use glMapBuffer 
to retrieve a 'void *' which you can then cast to a ctypes array of the 
correct size.

Pygame has no helping functions for OpenGL buffers or textures.

Alex.