This function used ugly hack with static variable which was
preventing some type checks in DAG nodes. Using this variable
form multiple threads is not considered safe, apparently.
Solved by moving this variable inside the DAGForest structure.
so it's global for the graph now, but different graphs does not
run into conflicts.
This required passing the forest to some functions, which doesn't
look so much nice, but don't want to spend time on making this
code look beautiful because it is really to be replaced by the
new dependency graph.
This is really bad bug actually which is must go to 'a'.
Graph traversal which is based on counting parents which are still
to be updated fails in cases there are cycles in the graph.
If there are cyclic dependencies in the scene all the objects from
the cycles will be updated in a single thread now one by one. This
makes blender behave the same way as it was before multi-threaded
DAG landed to master.
This needed to tweak depsgraph a bit so now dag_check_cycle() sets
is_acyclic field of DAG forest if there are cycles in the graph.
TODO: It might be possible to save some time on evaluation when
all the tagged objects were updated in multi-threaded DAG
traversal.
This solves threading conflict which happens when having
multiple objects using Curve Deform modifier with the same
curve datablock. This conflict was caused by the fact that
curve_deform_verts() used to temporary override curve's
flags to make it path is there.
Actually, it was setting CU_FOLLOW flag temporary which
was only used where_on_path() (only in terms that this
temporary assignment only affected this function) but it
is now commented out for a while, so no reason to set
this flag temporary, If it's ever to be done, we'll need
to pass flags as an additional function argument.
For the path creation i've extended DegNode structure
which now holds extra bits which indicates what additional
data depending on the graph topology is to be evaluated.
Currently this is only used to indicate that curve needs
path to be evaluated regardless to cu->flag state. This
is so Curve Deform modifier is always happy.
In the future this flag might also be used to indicate
whether bmesh verts are to update (see recent commit to
3-vertex parent crash fix) or to indicate that the object
is the motherball etc.
DAG node tagging was rather an experiment to make derived render working.
However, it ended up in a whole can of worms and need to be re-considered.
It is likely that regular object update tagging and scene update routines
are to be used for this.
Meanwhile no need to keep extra field in dag node. Would save us the whole
byte of the struct which we can use for other purposes meanwhile.
Summary:
Made objects update happening from multiple threads. It is a task-based
scheduling system which uses current dependency graph for spawning new
tasks. This means threading happens on object level, but the system is
flexible enough for higher granularity.
Technical details:
- Uses task scheduler which was recently committed to trunk
(that one which Brecht ported from Cycles).
- Added two utility functions to dependency graph:
* DAG_threaded_update_begin, which is called to initialize threaded
objects update. It will also schedule root DAG node to the queue,
hence starting evaluation process.
Initialization will calculate how much parents are to be evaluation
before current DAG node can be scheduled. This value is used by task
threads for faster detecting which nodes might be scheduled.
* DAG_threaded_update_handle_node_updated which is called from task
thread function when node was fully handled.
This function decreases num_pending_parents of node children and
schedules children with zero valency.
As it might have become clear, task thread receives DAG nodes and
decides which callback to call for it.
Currently only BKE_object_handle_update is called for object nodes.
In the future it'll call node->callback() from Ali's new DAG.
- This required adding some workarounds to the render pipeline.
Mainly to stop using get_object_dm() from modifiers' apply callback.
Such a call was only a workaround for dependency graph glitch when
rendering scene with, say, boolean modifiers before displaying
this scene.
Such change moves workaround from one place to another, so overall
hackentropy remains the same.
- Added paradigm of EvaluaitonContext. Currently it's more like just a
more reliable replacement for G.is_rendering which fails in some
circumstances.
Future idea of this context is to also store all the local data needed
for objects evaluation such as local time, Copy-on-Write data and so.
There're two types of EvaluationContext:
* Context used for viewport updated and owned by Main. In the future
this context might be easily moved to Window or Screen to allo
per-window/per-screen local time.
* Context used by render engines to evaluate objects for render purposes.
Render engine is an owner of this context.
This context is passed to all object update routines.
Reviewers: brecht, campbellbarton
Reviewed By: brecht
CC: lukastoenne
Differential Revision: https://developer.blender.org/D94
added some missing functions too - which are not used yep but should be there for api completeness.
* CDDM_set_mloop
* CDDM_set_mpoly
* BLI_mempool_count
Vertex parents were not requesting the original index layer, now do this as
part of depsgraph building, and make constraints with vertex groups use the
same system. Fix is based on patch by Campbell, but with some changes.
* Optimized RNA property lookups and path resolving, still can be
much better, but now the 1000 IPO example on bf-taskforce25
runs at reasonable speed.
* Also an optimization in the depsgraph when dealing with many
objects, this was actually also a bottleneck here.
The "Copy Size" constraint was calling a where_is_object(), this caused
the depsgraph to mess up in very weird ways and rare occasions. In the
sample file it showed strange lags in bones for using the "Stride bone"
option.
While trying to locate the bug I've revisited the Pose depsgraph in detail,
trying to figure out how it can print possible cycle errors in dependency.
That has been added now too (in console). Unfortunately the bugreport
example had no cycle errors. :)
Aim was to get a total refresh of the animation system. This
is needed because;
- we need to upgrade it with 21st century features
- current code is spaghetti/hack combo, and hides good design
- it should become lag-free with using dependency graphs
A full log, with complete code API/structure/design explanation
will follow, that's a load of work... so here below the list with
hot changes;
- The entire object update system (matrices, geometry) is now
centralized. Calls to where_is_object and makeDispList are
forbidden, instead we tag objects 'changed' and let the
depgraph code sort it out
- Removed all old "Ika" code
- Depgraph is aware of all relationships, including meta balls,
constraints, bevelcurve, and so on.
- Made depgraph aware of relation types and layers, to do smart
flushing of 'changed' events. Nothing gets calculated too often!
- Transform uses depgraph to detect changes
- On frame-advance, depgraph flushes animated changes
Armatures;
Almost all armature related code has been fully built from scratch.
It now reveils the original design much better, with a very clean
implementation, lag free without even calculating each Bone more than
once. Result is quite a speedup yes!
Important to note is;
1) Armature is data containing the 'rest position'
2) Pose is the changes of rest position, and always on object level.
That way more Objects can use same Pose. Also constraints are in Pose
3) Actions only contain the Ipos to change values in Poses.
- Bones draw unrotated now
- Drawing bones speedup enormously (10-20 times)
- Bone selecting in EditMode, selection state is saved for PoseMode,
and vice-versa
- Undo in editmode
- Bone renaming does vertexgroups, constraints, posechannels, actions,
for all users of Armature in entire file
- Added Bone renaming in NKey panel
- Nkey PoseMode shows eulers now
- EditMode and PoseMode now have 'active' bone too (last clicked)
- Parenting in EditMode' CTRL+P, ALT+P, with nice options!
- Pose is added in Outliner now, with showing that constraints are in
the Pose, not Armature
- Disconnected IK solving from constraints. It's a separate phase now,
on top of the full Pose calculations
- Pose itself has a dependency graph too, so evaluation order is lag free.
TODO NOW;
- Rotating in Posemode has incorrect inverse transform (Martin will fix)
- Python Bone/Armature/Pose API disabled... needs full recode too
(wait for my doc!)
- Game engine will need upgrade too
- Depgraph code needs revision, cleanup, can be much faster!
(But, compliments for Jean-Luc, it works like a charm!)
- IK changed, it now doesnt use previous position to advance to next
position anymore. That system looks nice (no flips) but is not well
suited for NLA and background render.
TODO LATER;
We now can do loadsa new nifty features as well; like:
- Kill PoseMode (can be option for armatures itself)
- Make B-Bones (Bezier, Bspline, like for spines)
- Move all silly button level edit to 3d window (like CTRL+I = add
IK)
- Much better & informative drawing
- Fix action/nla editors
- Put all ipos in Actions (object, mesh key, lamp color)
- Add hooks
- Null bones
- Much more advanced constraints...
Bugfixes;
- OGL render (view3d header) had wrong first frame on anim render
- Ipo 'recording' mode had wrong playback speed
- Vertex-key mode now sticks to show 'active key', until frame change
-Ton-
Works like a charm... well it now replaces the old base-sorting hack. :)
Next stage will be to define how to further integrate it. Plus some
minor code cleanups... static/internal functions versus external, etc.
