BF-admins agree to remove header information that isn't useful,
to reduce noise.
- BEGIN/END license blocks
Developers should add non license comments as separate comment blocks.
No need for separator text.
- Contributors
This is often invalid, outdated or misleading
especially when splitting files.
It's more useful to git-blame to find out who has developed the code.
See P901 for script to perform these edits.
Some summary of changes:
- Don't use DEG prefix for types and enumerator values:
the code is already inside DEG namespace.
- Put code where it locally belongs to: avoid having one
single header file with all sort of definitions in it.
- Take advantage of modern C++11 enabled by default.
Textures are now hooked up to the RESET operation of particle
settings, which ensures particles being re-distributed when
texture is changed.
This is limited to a direct user modifications, which matches
old behavior in 2.79.
The issue was caused by transflag set in geometry evaluation
never copied back top original object.
Now we have a dedicated operation which does all sort copy
back to original object, so we don't have to worry about
atomic assignments or what gets set where.
Still need to move boundbox to the same function, but it
needs some careful doublechecking first.
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.
This allows to force duplicated object to be fully evaluated for
display/draw.
Previously only transform component of duplicated object was
forced to become evaluated.
Currently done for mesh batch cache update, and for base flags sync.
Those components do not need anything from original object, and hence
can skip CoW tag and have faster update after them used.
- When returning the number of items in a collection use BLI_*_len()
- Keep _size() for size in bytes.
- Keep _count() for data structures that don't store length
(hint this isn't a simple getter).
See P611 to apply instead of manually resolving conflicts.
This code was disable a while back and got re-enabled by some previous debug
process. Having relation names in dot file helps understanding what's going
on in one cases, but makes things spread too far away in others.
One thing i'm not fully happy with is all this is_same_* functions. Need to
get rid of this by probably adding explicit entry/init/whatever nodes and
maybe making node criteria aware of whether key will be used as "from" or
as "to" node.
This statistics is only collected when debug_value is different from 0.
Stored in depsgraph node itself, so we can always have access to average data
and other stats which requires persistent storage. This way we also don't waste
time trying to find stats from a separately stored hash map.
This is something deliver form node type, there is no reason to try cache it
anywhere, especially since it's not used in any performance critical code.
Lighter weight dependency graph is what we want.
This is crucial bit since batch cache is stored in the evaluated object,
meaning we can't tag it's hatch cache dirty from the notifier system.
Not easily at least. Better to leave this job to depsgraph, it knows
all the copies of data.
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.
< 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.
