Prelimenary step to fix T77460.
Not sure how or when that thing was done, but since that call walks
around collections relationships, it's an utterly critical violation of
liblinking principles (code here should never, ever 'get outside' of its
own ID scope).
This was wroking so far only because code called through this function
(`BKE_collection_parent_relations_rebuild`) was only following parents
pointers (in `BKE_collection_find_cycle()`), which would be either valid
or non-existent.
But next commit is going to change that to also check collection's
objects instancing of other collections.
The current particle state is stored in a `CustomData` instance and
the cache is stored in `PointCache`.
The current state exists on the copy-on-write copies of the simulation,
while the cache only exists in the original data block.
This patch implements a temporary trivial particle simulation that does not
use the node system yet. It is used for testing and will be replaced soon.
`PointCache` still has some limitations that need to be overcome using
separate refactorings. For example, we need to be able to store the number
of particles in the point cache. Also we need to change which attributes
are stored for a particle system more dynamically than is currently possible afaik.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D7836
This is a critical fix that should also be backported to 2.83.1
Fairly stupid bug in fact, code detecting changes across undo steps was
assuming that each BHEAD (a block of data in blendfiles) would not be larger
than one memory chunk... Which is the case in alsmost every situation,
besides some super-heavy geometries, and other similar things (images
would also be affected e.g.).
Design Task: T76372
This part of a larger refactoring towards a more extensible architecture
in Blender: T75724
The API is defined in `BLO_read_write.h`. It adds the small data structures
`BlendWriter`, `BlendDataReader`, `BlendLibReader` and `BlendExpander`.
Those contain context about the current read/write operation. Furthermore,
it adds many functions with the prefixes `BLO_write_*`, `BLO_read_*` and
`BLO_expand_*`.
Lib linking and expanding will probably be handled by the more generic libquery
system eventually. The corresponding parts of the API can be removed then.
Mix up with imapaint.paintcursor & imapaint.paint.paint_cursor
Remove imapaint.paintcursor since it wasn't used.
Also rename paint_cursor_start_explicit() to paint_cursor_start(),
removing the existing paint_cursor_start() since it took the paint
struct from the context, a value that's known by all callers.
* Simplify workspace API a bit
* Comment on behavior of workspace-layout relations where exposed in API
* Remove annoying getters/setters
* Avoid lookups if we can early exit
* A NULL check is removed in `direct_link_workspace()` that I don't see
a need for. Am not 100% sure though, fingers crossed.
In general these changes should improve readability and make things
easier to reason about.
