around the volume.
We generate a tight mesh around the active voxels of the volume in order
to effectively skip empty space, and start volume ray marching as close
to interesting volume data as possible. See code comments for details on
how the mesh generation algorithm works.
This gives up to 2x speedups in some scenes.
Reviewed by: brecht, dingto
Reviewers: #cycles
Subscribers: lvxejay, jtheninja, brecht
Differential Revision: https://developer.blender.org/D3038
This is more important now that we will have tigther volume bounds that
we hit multiple times. It also avoids some noise due to RR previously
affecting these surfaces, which shouldn't have been the case and should
eventually be fixed for transparent BSDFs as well.
For non-volume scenes I found no performance impact on NVIDIA or AMD.
For volume scenes the noise decrease and fixed artifacts are worth the
little extra render time, when there is any.
Now the only missing bit seems to be in Cycles to pass depsgraph to
builtin_image_float_pixels().
Ideally we could get evaluation context instead of using depsgraph + settings.
But for the other rna EvaluationContext functions this is how we are doing.
Reviewers: sergey, brecht
Differential Revision: https://developer.blender.org/D3087
This still does not make point density to work in Cycles, but at least it pass
the depsgraph down the line.
Note this was working fine before the depsgraph/render refactor to pass
evaluated depsgraph to the engines.
User notes
----------
Compositing, rendering of multi-layers in Eevee should be fully working now.
Development notes
-----------------
Up until now we were still using the same depsgraph for rendering and viewport
evaluation. And we had to go out of our ways to be sure the depsgraphs were
updated.
Now we iterate over the (to be rendered) view layers and create a depsgraph to
each one, fully evaluated and call the render engines (Cycles, Eevee, ...) with
this viewlayer/depsgraph/evaluation context.
At this time we are not handling data persistency, Depsgraph is created from
scratch prior to rendering each frame. So I got rid of most of the partial
update calls we had during the render pipeline.
Cycles: Brecht Van Lommel did a patch to tackle some of the required Cycles
changes but this commit mark these changes as TODOs. Basically Cycles needs to
render one layer at a time.
Reviewers: sergey, brecht
Differential Revision: https://developer.blender.org/D3073
Similar to the Principled BSDF, this should make it easier to set up volume
materials. Smoke and fire can be rendererd with just a single principled
volume node, the appropriate attributes will be used when available. The node
also works for simpler homogeneous volumes like water or mist.
Differential Revision: https://developer.blender.org/D3033
We now continue transparent paths after diffuse/glossy/transmission/volume
bounces are exceeded. This avoids unexpected boundaries in volumes with
transparent boundaries. It is also required for MIS to work correctly with
transparent surfaces, as we also continue through these in shadow rays.
The main visible changes is that volumes will now be lit by the background
even at volume bounces 0, same as surfaces.
Fixes T53914 and T54103.
It seems to be useful still in cases where the particle are distributed in
a particular order or pattern, to colorize them along with that. This isn't
really well defined, but might as well avoid breaking backwards compatibility
for now.
This is like the only way to add variety to hair which is created
using simple children. Used here for the hair.
Maybe not ideal, but the time will show.
Burley SSS uses a bit of strange thing where the albedo and closure weight are
different, which makes the subsurface color act a bit like a subsurface radius
indirectly by the way the Burley SSS profile works.
This can't work for random walk SSS though, and it's not clear to me that this
is actually a good idea since it's really the subsurface radius that is supposed
to control this. For now I'll leave Burley SSS working the same to not break
backwards compatibility.
