Blob stands for "binary large object" and is a known term. I used to use the term `bdata`
to mean "binary data", mainly because I didn't think of a better name. Blob is a much
better name as it captures the intend of those files much better.
This change breaks existing bakes, because I rename the folder from `bdata` to `blobs`.
I think that is ok, because I also just broke bakes two days ago in a larger refactor
(e92c59bc9b).
Pull Request: https://projects.blender.org/blender/blender/pulls/111822
Goals of the refactor:
* Internal support for baking individual simulation zones (not exposed in the UI yet).
* More well-defined access to simulation data in geometry nodes. Especially, it
should be more obvious where data is modified. A similar approach should also
work for the Bake node.
Previously, there were a bunch of simulation specific properties in `GeoNodesModifierData`
and then the simulation input and output nodes would have to figure out what to do with that
data. Now, there is a new `GeoNodesSimulationParams` which controls the behavior of
simulation zones. Contrary to before, different simulation zones can now be handled
independently, even if that is not really used yet. `GeoNodesSimulationParams` has to be
subclassed by a user of the geometry nodes API. The subclass controls what each simulation
input and output node does. This some of the logic that was part of the node before, into
the modifier.
The way we store simulation data is "transposed". Previously, we stored zone data per
frame, but now we store frame data per zone. This allows different zones to be more
independent. Consequently, the way the simulation cache is accessed changed. I kept
things simpler for now, avoiding many of the methods we had before, and directly
accessing the data more often which is often simple enough. This change also makes
it theoretically possible to store baked data for separate zones independently.
A downside of this is, that existing baked data can't be read anymore. We don't really
have compatibility guarantees for this format yet, so it's ok. Users will have to bake again.
The bake folder for the modifier now contains an extra subfolder for every zone.
Drawing the cached/baked frames in the timeline is less straight forward now. Currently,
it just draws the state of one of the zones, which usually is identical to that of all other
zones. This will change in the future though, and then the timeline drawing also needs
some new UI work.
Pull Request: https://projects.blender.org/blender/blender/pulls/111623
Jacques Lucke