The issue was caused by dependency cycle solver killing relation
which was guaranteed various things: i.e. copy-on-write component
orders and pose evaluation order (which must first run pose init
function).
Now it is possible to prevent such relations from being ignored.
This is not a complete fix, but is enough to make this specific
rig to work. Ideally, we also need to run copy-on-write operation
prior to anything else.
Among all the lines moved around, the general idea is quite simple.
Actually, there are two ideas implemented there.
First one, is when object itself is tagged for update, we tag its
point cache component for evaluation, which makes it so point cache
is properly reset. We do it implicitly because otherwise we'll need
to go everywhere and add explicit tag in almost all the properties.
Second thing is, we link all collider and force fields to a point
cache component using special type of link. This type of link only
allows flush if change is caused by a user update. This way reset
does not happen when change is caused due to animation, but will
properly happen when user causes indirect change to the objects
which are part of physics simulation.
We already had a BKE_main.h header, no reason not to put there
Main-specific functions, BKE_library has already more than enough to
handle with IDs and library management!
To find all effectors in the scene, we need to loop over all objects.
Doing this during depsgraph evaluation caused crashes because not all
objects are guaranteed to be evaluated yet.
To fix this, we now cache the relations as part of the dependency graph
build. As a bonus this also makes evaluation faster for big scenes,
since looping over all objects for each particle system is slow.
Fixes T55156.
When active dependency graph is evaluated, it will apply animation,
drivers and scalar evaluation data (such as object matrix) to an
original datablock. This way operators and tools can easily read
data from original datablock.
This will simplify porting them to copy-on-write, and solve issues
when some operator will allocate new datablock based on original one,
and will want to read data from it.
This introduces a new depsgraph API for getting updated datablocks,
rather than getting it from bpy.data.
* depsgraph.ids_updated gives a list of all datablocks in the depsgraph
which have been updated.
* depsgraph.id_type_updated('TYPE') is true if any datablock of the given
type has been added, removed or modified.
More API updates are coming to properly handle multiple depsgraphs and
finer update granularity, but this should make Cycles work again.
Scene, view layer and mode are now set in the constructor and never changed.
Time is updated on frame changes to indicate which frame is being or has been
evaluated last.
This is a step towards making EvaluationContext obsolete.
Differential Revision: https://developer.blender.org/D3144
The idea is to allow iterating over ID nodes in exact order of their
construction, and in order which will not change dependent on memory
pointers or anything.
The RenderResult struct still has a listbase of RenderLayer, but that's ok
since this is strictly for rendering.
* Subversion bump (to 2.80.2)
* DNA low level doversion (renames) - only for .blend created since 2.80 started
Note: We can't use DNA_struct_elem_find or get file version in init_structDNA,
so we are manually iterating over the array of the SDNA elements instead.
Note 2: This doversion change with renames can be reverted in a few months. But
so far it's required for 2.8 files created between October 2016 and now.
Reviewers: campbellbarton, sergey
Differential Revision: https://developer.blender.org/D2927
This is a final step of having proper ownership. Now selecting different
layers in the "top bar" will actually do what this is expected to do.
Surely, there are still things to be done under the hood, that will happen
in a less intrusive way.
The idea is to allow iterating over ID nodes in exact order of their
construction, and in order which will not change dependent on memory
pointers or anything.
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.
Previously it was possible to run into situation when armature is constructed prior to
objects which are used for it's constraints. This was causing wrong scene evaluation.
Now we create placeholders for objects used by armature in case they don't have ID node
yet, which ensures we have proper mapping from original to copy-on-write ID pointer.
< Dependency graph Copy-on-Write >
--------------------------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
This is an initial commit of Copy-on-write support added to dependency graph.
Main priority for now: get playback (Alt-A) and all operators (selection,
transform etc) to work with the new concept of clear separation between
evaluated data coming from dependency graph and original data coming from
.blend file (and stored in bmain).
= How does this work? =
The idea is to support Copy-on-Write on the ID level. This means, we duplicate
the whole ID before we cann it's evaluaiton function. This is currently done
in the following way:
- At the depsgraph construction time we create "shallow" copy of the ID
datablock, just so we know it's pointer in memory and can use for function
bindings.
- At the evaluaiton time, the copy of ID get's "expanded" (needs a better
name internally, so it does not conflict with expanding datablocks during
library linking), which means the content of the datablock is being
copied over and all IDs are getting remapped to the copied ones.
Currently we do the whole copy, in the future we will support some tricks
here to prevent duplicating geometry arrays (verts, edges, loops, faces
and polys) when we don't need that.
- Evaluation functions are operating on copied datablocks and never touching
original datablock.
- There are some cases when we need to know non-ID pointers for function
bindings. This mainly applies to scene collections and armatures. The
idea of dealing with this is to "expand" copy-on-write datablock at
the dependency graph build time. This might introduce some slowdown to the
dependency graph construction time, but allows us to have minimal changes
in the code and avoid any hash look-up from evaluation function (one of
the ideas to avoid using pointers as function bindings is to pass name
of layer or a bone to the evaluation function and look up actual data based
on that name).
Currently there is a special function in depsgraph which does such a
synchronization, in the future we might want to make it more generic.
At some point we need to synchronize copy-on-write version of datablock with
the original version. This happens, i.e., when we change active object or
change selection. We don't want any actual evaluation of update flush happening
for such thins, so now we have a special update tag:
DEG_id_tag_update((id, DEG_TAG_COPY_ON_WRITE)
- For the render engines we now have special call for the dependency graph to
give evaluated datablock for the given original one. This isn't fully ideal
but allows to have Cycles viewport render.
This is definitely a subject for further investigation / improvement.
This call will tag copy-on-write component tagged for update without causing
updates to be flushed to any other objects, causing chain reaction of updates.
This tag is handy when selection in the scene changes.
This basically summarizes ideas underneath this commit. The code should be
reasonably documented.
Here is a demo of dependency graph with all copy-on-write stuff in it:
https://developer.blender.org/F635468
= What to expect to (not) work? =
- Only meshes are properly-ish aware of copy-on-write currently, Non-mesh
geometry will probably crash or will not work at all.
- Armatures will need similar depsgraph built-time expansion of the copied
datablock.
- There are some extra tags / relations added, to keep things demo-able but
which are slowing things down for evaluation.
- Edit mode works for until click selection is used (due to the selection
code using EditDerivedMesh created ad-hoc).
- Lots of tools will lack tagging synchronization of copied datablock for
sync with original ID.
= How to move forward? =
There is some tedious work related on going over all the tools, checking
whether they need to work with original or final evaluated object and make
the required changes.
Additionally, there need synchronization tag done in fair amount of tools
and operators as well. For example, currently it's not possible to change
render engine without re-opening the file or forcing dependency graph for
re-build via python console.
There is also now some thoughts required about copying evaluated properties
between objects or from collection to a new object. Perhaps easiest way
would be to move base flag flush to Object ID node and tag new objects for
update instead of doing manual copy.
here is some WIP patch which moves such evaluaiton / flush:
https://developer.blender.org/F635479
Lots of TODOs in the code, with possible optimization.
= How to test? =
This is a feature under heavy development, so obviously it is disabled by
default. The only reason it goes to 2.8 branch is to avoid possible merge
hell.
In order to enable this feature use WITH_DEPSGRAPH_COPY_ON_WRITE CMake
configuration option.
Was rather weird and only used for time source. It is simpler to make depsgraph
to keep track of time source directly.
No need to introduce extra entitites without actual need.
It was never actually used apart from being stored at a construciton time.
This caused some redundancy and ncertanty about which relation type to use
during construciton (often existing types were not close enough to particular
use case).
These bits became obsolete with the new layer system, so we can
simplify some code around them or avoid existing workarounds which
were trying to keep things working for them.
There are still work needed to be done for on_visible_change to
avoid unnecessary updates, but that can also happen later.
There is no real reason to have nodes storing heap-allocated name
and description. Doing this increases amount of allocations during
dependency graph building, which usually means somewhat slowness.
We're temporarily loosing some eyecandy in the graphviz visualizer,
but those we can bring back as a part of graphiz dump (which happens
much less often than depsgraph build).
This will happen in multiple commits for the ease of bisect in the
future just in case this causes any regression. This commit contains
ID creation API changes.
This is mainly a maintenance commit which was aimed to make work with
this module more pleasant and solve such issues as:
- Annoyance with looong files, which had craftload in them
- Usage of STL for the data structures we've got in BLI
- Possible symbol conflicts
- Not real clear layout of what is located where
So in this commit the following changes are done:
- STL is prohibited, it's not really predictable on various compilers,
with our BLI algorithms we can predict things much better.
There are still few usages of std::vector, but that we'll be
solving later once we've got similar thing in BLI.
- Simplify foreach loops, avoid using const_iterator all over the place.
- New directory layout, which is hopefully easier to follow.
- Some files were split, some of them will be split soon.
The idea of this is to split huge functions into own files with
good documentation and everything.
- Removed stuff which was planned for use in the future but was never
finished, tested or anything.
Let's wipe it out for now, and bring back once we really start using
it, so it'll be more clear if it solves our needs.
- All the internal routines were moved to DEG namespace to separate
them better from rest of blender.
Some places now annoyingly using DEG::foo, but that we can olve by
moving some utility functions inside of the namespace.
While working on this we've found some hotspot in updates flush, so
now playback of blenrig is few percent faster (something like 96fps
with previous master and around 99-100fps after this change).
Not saying it's something final, there is still room for cleanup and
API simplification, but those might happen as a regular development
now without doing any global changes.
