The is following: split copy on write update for node trees, and if we are only
tagging for uniform buffer update we skip whole datablock copy and only invoke
copy default_values form original nodetree to a copied one.
Thing which i'm not sure is: whether we need to use different branches in graph
itself to control such a conditional behavior, or whether we need to store tag
somewhere in the dependency graph. There are obviously cons and pros in both
approaches, and need to think about this. Maybe with more examples it becomes
more obvious which way is better.
This only fixes manual tweaks for now, animation support is coming.
There were two issues here:
1. material_update did not do anything, because DEG_id_tag_update was storing
update tags in original IDs, which had nothing evaluated. Even more, material
update should have been called with evaluated version of material, Solved
this by copying update tag from original ID to a copied one.
However, perhaps DEG_id_tag_update should tag both original and copied ID,
so updates are never gets lots if some depsgraph is not visible.
2. Tagging material for update should ensure it's copied version of node tree is
up to date, otherwise material will still use old node tree.
This solves missing material updates when changing topology. Tweaking values is
still broken, because of GPUMaterial using pointer to original node's socket
value, which gets broken after copy-on-write of the node tree (pointers of nodes
are changing).
Originally we were not respecting the original visibility flags of the
collections. However this is required for Copy-on-write (CoW).
Remember to update the svn lib tests folder. I had to update some of the
json files there.
Also adding a new unittest for this particular issue:
Test render_layer_scene_copy_f
This commit is a work forward having less updates during playback, which speeds
things up a lot here. The idea is simple: stop update all copy-on-write
datablocks (which implies full re-evaluation actually) on frame change and
re-use existing evaluated meshes as much as possible.
This brings playback speed to 24 fps on the dino test scene here. Performance
drops down a lot when armature is animated tho, but that's because of need of
tangent space calculation which we can't do much about from just a dependency
graph.
Hopefully this doesn't make copy-on-write too unstable, quick tests here are
surviving fine.
BKE_scene_copy explicitly ignores visibility of "source" collections make all
collections visible. This is also tested by regression tests.
While it seems more logical to simply preserve all possible visibility flags
and overrides, don't feel like submitting to a behavior-changes without talking
to author of those guards first.
This commit fixes cycles material preview.
If object is only listed in collection but not added to any of layers we shouldn't create
placeholder for it, because otherwise we'll leave lots of placeholder ID nodes.
Question: can we make this exception to be more reliable?
