Based on investigation by sergey (Sergey Sharybin) and revzin (Grigory Revzin).
Based on patch D460 by revzin (Grigory Revzin).
Differential Revision: https://developer.blender.org/D460
Thing is, those functions always reallocate the whole keyblock's data mem,
while in some cases we already have right amount of elements, so we can just
copy over. Further more, `BKE_key_convert_from_offset`, despite its name,
was not making any check nor allocation on keyblock's data elements!
So split 'copy' operation itself in `BKE_key_update_from_...`,
where no mem checks/operations are performed (only an assert).
Only useful in sculpt mode currently, but will be used by fix for T35170 too.
For FCurves where all the keyframes use the "simple" interpolation types
(i.e. Constant, Linear, and Bezier), we now use the old FCurve drawing
code that was used prior to the Easing Equations changes. This should
be generally faster in general.
When the "High Quality Line Drawing" option (View menu) is disabled,
the sampling rate (i.e. the size of timesteps to use when sampling
the FCurve for drawing it in most cases now) is set to be quite low
(i.e. at 0.1 frame increments). This amounts to at most 10 sub-steps.
In one test file (with a wide window), this had the effect of improving
the performance by over 3x. It's still not as good as a sampling-free
approach, but for this functionality is still needed for FModifiers,
so it's better that we can optimise this.
When the active action is a NLA strip, the keyframe indicator colors for buttons
and the 3D view indicator (i.e. the current frame indicator changes color) didn't
work correctly. This was because they were still checking for keyframes in
"global" time space, whereas they needed to be applying NLA corrections to
"look inside" the remapped action.
In fact, any button controlling a whole array of values were broken
because they always only keyed the index of the single fcurve returned
by `ui_but_get_fcurve()`, now pass button's rna_index value instead.
Recent flag re-order broke it since bits overlap, but logic here was far too complicated & fragile,
Checked the type of each button when testing which direction to handle events as well as block direction.
Now store the block-flipped state as a flag.
too crowded.
UVs in the same layer can be used for many images. It used to be
possible to filter UV faces based on the image, but this is impossible
now due to the way the system works, so I added an option to allow
filtering UVs based on active material index.
Rationale on using option and not being smart here (options are bad tm)
is that for some workflows, such as preserving image space by using the
same image for many materials, people might want to turn this off.
layer index was being obtained for loop data types but we referenced
Tessface data types
NULLing those out since only the data offsets are used in edit mode and
address sanitizer complains about freed memory access.
Also minor comment in texpainting
Make the UI API more consistent and reduce confusion with some naming.
mainly:
- API function calls
- enum values
some internal static functions have been left for now
