[Bf-cycles] OSL Slower with Unpacked Textures?

Sergey Sharybin sergey.vfx at gmail.com
Mon Apr 4 16:01:06 CEST 2016

This is because OSL uses smarter filtering of a textures (sampling it over
ellipse size of which depends on ray differentials). This causes slower
sampling but solves noise in certain situations.

However, when the images are packed we're by-passing all OSL sampling code
(because OSL does not support images loaded into memory) and do much
simpler sampling, which is faster but also noisier (again, in certain

So it's not a bug, just a difference in image sampling. We might need to
slow SVM's sampling as well to support mipmaps and such tho..

On Mon, Apr 4, 2016 at 3:55 PM, Zauber Paracelsus <zauber at gridmail.org>

> I had been watching a video on youtube showing how to speed up renders
> with Open Shading Language (I can't paste the link, or else the mailing
> list rejects the message as spam).  Apparently, the secret trick is to
> pack your textures.
> Is this a known shortcoming of OSL, or is it a bug in blender's
> implementation of OSL?
> _______________________________________________
> Bf-cycles mailing list
> Bf-cycles at blender.org
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With best regards, Sergey Sharybin
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