[Gegl-developer] Introduction to GEGL Buffers

[Jerson Michael Perpetua]

Thanks Nicolas.  I've seen the video just this morning.  As expected,
it turned out to be my general definition of "awesomeness".  He
discussed quite a few pitfalls that should apply and not apply to
GEGL.  Quite particular is pitfall #4 where he got ~500ms to render
the image but got it transfered from the GPU back to the CPU in ~3
seconds!  That's just crazy!

Hopefully, we will be able to dodge that issue by uploading textures
whilst the GPU is computing.  This needs the rectangle-level CPU
parallelization we are discussing as of the moment.  I am now
convinced that the latter parallelization is needed to extract the
GPU's (evil) power.

Another issue not discussed by the talk is OpenGL texture formats.  I
suspect (though I'm not quite sure, like I always am :) that Nona-GPU
doesn't deal with different color formats.  OpenGL can only process
1-4 tuples of vector data in the shader level, so I can't imagine how
we can provide support for Babl formats with channels exceeding 4.
Also, current generation GPUs don't support double-precision floating
point data.  Providing support for RGBA doubles, for example, is
difficult.


Kind regards,
Daerd