This is sort of extension of existing Use Environment option which now allows to
disable AO on the render layer basis.
Useful in cases like disabling AO for the background because it might make it
too flat and so.
Reviewers: juicyfruit, dingto, brecht
Reviewed By: brecht
Subscribers: eyecandy, venomgfx
Differential Revision: https://developer.blender.org/D1633
* If a Background node is set to a black color or zero strength,
it now gets removed from the shader graph.
* In case the graph is empty (no background node), the kernel will skip
evaluating it and save some rendertime. This can help quite a bit in scenes,
where the majority of the image consists of a black background.
Example: http://www.pasteall.org/pic/show.php?id=82650
In this case the render is ~16% faster.
Differential Revision: https://developer.blender.org/D972
* Add alpha pass output, to use set Transparent option in Film panel.
* Add Holdout closure (OSL terminology), this is like the Sky option in the
internal renderer, objects with this closure show the background / zero
alpha.
* Add option to use Gaussian instead of Box pixel filter in the UI.
* Remove camera response curves for now, they don't really belong here in
the pipeline, should be moved to compositor.
* Output full float values for rendering now, previously was only byte precision.
* Add a patch from Thomas to get a preview passes option, but still disabled
because it isn't quite working right yet.
* CUDA: don't compile shader graph evaluation inline.
* Convert tabs to spaces in python files.
