[Bf-committers] Compositing output while editing

[Sergey Sharybin]

This change is very much what i was keeping in mind. The only thing is that
sometimes it could be nice to be able to composite Render Result while
editing. And that's why i asked question here -- want to have a bit more of
artists' opinions.

As per issue you're mentioning, my guess is that's it's not so much work to
remove Render Result/Previews clearing we\hen running compo. But didn't
check on code and let's wait for a bit of feedback :)

Currently previews will only be affected by the border. But there're some
ideas here. We'll need to implement percentage for compositor -- so you'll
be able to use the same node setup, tweak render percentage and don't wary
about nodes and result. This is what 4K ToS will benefit a lot. And once
it's implemented previews could use the same technique actually -- they
could easily use 25% of resolution.

Cache eeh... 4K ToS already showed compositor is not friendly with memory.
Don't want to make it use even more memory.


On Sat, Mar 9, 2013 at 10:03 PM, Lukas Tönne <lukas.toenne at gmail.com> wrote:

> After some discussion on IRC i made a quick simple patch to avoid full
> composite recalc after each node edit:
>
> http://www.pasteall.org/40351/diff
>
> Without this all potential output nodes are enabled both in preview
> and full composite executions. The patch separates this, doing preview
> and viewer calculation only on preview runs (i.e. automatic updates
> after tweaking nodes) while composite output and file output nodes
> only run on full composite executions (pressing F12). It already seems
> to improve editing quite a bit, only issue it seems is that the
> previous render result and previews are discarded in both cases,
> leaving either one un-calculated after updating the other (F12 ->
> previews get lost, node edit -> render result gets lost).
>
> Some other possible improvements discussed:
>
> 1) Restriced and/or scaled viewer image: Sergey has already been
> working on a composite border feature AFAIK, for reducing the amount
> of work done in viewer updates
>
> 2) Re-use buffers calculated by viewers and composite output
> respectively. This will require a working cache system so the buffers
> don't get lost each time between updates. I posted a prerequisite
> patch a while ago, this should allow the compositor cache to further
> reduce executions to outdated parts:
> http://lists.blender.org/pipermail/bf-committers/2013-January/039013.html
>
> 3) Allow recomposite without requiring full render every time (as
> happens on F12). I think the current solution involves making a
> "compositing scene" with no mesh data and only a compositing setup
> using images, but that's a bit of a workaround it seems. It shouldn't
> be hard to make an operator that only executes the compositor without
> rendering (the opposite, render without composite, can be done simply
> by disabling Compositing in Post Processing panel). There might even
> be a feature for this i don't know about, since Sebastian said it
> existed in 2.49 ...
>
> On Sat, Mar 9, 2013 at 2:58 PM, Sergey Sharybin <sergey.vfx at gmail.com>
> wrote:
> > Hi,
> >
> > Noticed that currently compositor output node will be fully recalculated
> > every time you're editing compositor node tree. This adds quite enough of
> > CPU consumption and only benefit from this is having Render Result image
> > up-to-date.
> >
> > Is it something indeed expected by artists? From what i've noticed during
> > Mango and some post-mango artists feedback -- they're usually
> disconnecting
> > compo output node to make compositing faster. But this often leads to
> > troubles when you forget to connect node back, send 12hrs shot to the
> farm
> > and.. Well, nothing fun out of this.
> >
> > So, the question is: is it even helpful to have Render Result updating
> > every time you're editing the tree? And if so, what about:
> >
> > - Making it a compositor option to ignore compo output while editing
> > - Making it possible to mute compo output node, which will mean it's
> > ignored while editing (but not while rendering)
> >
> > --
> > With best regards, Sergey Sharybin
> > _______________________________________________
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-- 
With best regards, Sergey Sharybin