User notes
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Compositing, rendering of multi-layers in Eevee should be fully working now.
Development notes
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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
Still not ideal but getting closer. Main annoying thing so far is
dependency of Render structure for now. It is used to switch particles
to render mode and could probably also be eliminated.
* Surface bake data is no longer recalculated every frame, but only when surface mesh has moved/transformed. Results in multiple times better performance on high resolution surfaces when using sub-steps or surface is still.
* Heavily optimized particle brushes when random particle size enabled. Up to 10x speedup with large radius particles.
* Added an additional "grid" space partitioning structure for surfaces.
* Added bounding box checks for brushes.
* Smaller overall optimization.
* Further OpenMP parallelization.
* Added physics tab link to modifier panel.
* Fix: "Point Density" texture cache wasn't properly updated. Brushes can now use Point Density textures as well.
* Fix: Paint dissolve resulted in black color.
* Fix: KD-tree checkups weren't completely thread safe. Fixes possible crash with OpenMP enabled particle brushes.
* Fix: When brush was set to use a specific material, it was saved incorrectly and resulted in potential crashes on next load.
Removed all the old particle rendering code and options I had in there
before, in order to make way for...
A new procedural texture: 'Point Density'
Point Density is a 3d texture that find the density of a group of 'points'
in space and returns that in the texture as an intensity value. Right now,
its at an early stage and it's only enabled for particles, but it would be
cool to extend it later for things like object vertices, or point cache
files from disk - i.e. to import point cloud data into Blender for
rendering volumetrically.
Currently there are just options for an Object and its particle system
number, this is the particle system that will get cached before rendering,
and then used for the texture's density estimation.
It works totally consistent with as any other procedural texture, so
previously where I've mapped a clouds texture to volume density to make
some of those test renders, now I just map a point density texture to
volume density.
Here's a version of the same particle smoke test file from before, updated
to use the point density texture instead:
http://mke3.net/blender/devel/rendering/volumetrics/smoke_test02.blend
There are a few cool things about implementing this as a texture:
- The one texture (and cache) can be instanced across many different
materials:
http://mke3.net/blender/devel/rendering/volumetrics/pointdensity_instanced.png
This means you can calculate and bake one particle system, but render it
multiple times across the scene, with different material settings, at no
extra memory cost.
Right now, the particles are cached in world space, so you have to map it
globally, and if you want it offset, you have to do it in the material (as
in the file above). I plan to add an option to bake in local space, so you
can just map the texture to local and it just works.
- It also works for solid surfaces too, it just gets the density at that
particular point on the surface, eg:
http://mke3.net/blender/devel/rendering/volumetrics/pointdensity_solid.mov
- You can map it to whatever you want, not only density but the various
emissions and colours as well. I'd like to investigate using the other
outputs in the texture too (like the RGB or normal outputs), perhaps with
options to colour by particle age, generating normals for making particle
'dents' in a surface, whatever!
