[Bf-committers] Zcombine node + alpha channel issue

[GSR]

Hi,
cedricpaille at gmail.com (2008-04-14 at 1142.59 +0200):
> I was playing with this node, add saw that the alpha channel for each images
> was not taken into account.
> I use an external renderer (Pixie) with my Blender rib exporter and export Z
> and A channels and when I motion blur, the result is not what I expected
> (only Z do the mask).

There was a patch about that, in which zcombine used alpha over ops
based in which thing was over what. I can look it up, it must be
somewhere.

> I made this tweak to CMP_zcombine.c to make it work:
[Something like looks like alpha over op, but coded by hand ;] ]
> But It works only when "Save Buffers" and "Full Sample" is enabled on the
> "output" render panel.
> The other case seems a bit harder to code (with the current implementation).

The patch had special handling for antiaaliased / crossing surfaces,
so it worked acceptably well, and before full sample was implemented.
It was rejected.

GSR