Blender Git Loki

Workbench: Depth Of Field: Initial Commit

The algorithm used is borrowed from :
http://tuxedolabs.blogspot.com/2018/05/bokeh-depth-of-field-in-single-pass.html

This makes it possible to have a decent blur for foreground over defocused
background in one pass only.

The algorithm is using a gather approach that is much faster
than the scatter approach used in Eevee. This makes it possible to have
custom bokeh shapes (not implemented yet) which would be impossible with
a separable gaussian technique.

The blur is done in 2 steps. The first one define the shape of the bokeh
and the second that fill the undersampling.

A downsample max-CoC tile texture speed up the gathering process.