The cause of the crash was identified in an uninitialized member variable
`Main->lock`. Now that struct Main has a few member variables whose
values are dynamically allocated, per-render Freestyle-specific Main data
structures will be allocated and released using `BKE_main_new()` and
`BKE_main_free()`, respectively.
This revision complements the commit rB6135556f4556.
A bit hackish solution for now, cleaner solution we'll look into as a
part of the new DAG project, when it's clear what kind of data is passed
to the evaluation callbacks.
Probably a leftover from old code, I don't think this invoke usage of VIEW3D_OT_background_image_add
was actually reachable anywhere from the UI, but managed to get it working from py, without increasing
user count...
Preserve buffer form previous runs so it's possible to make
a compo of full frame, then draw a border and start tweaking
nodes and see updates in that border.
Main idea is to make it able to visually compare difference
between what was changed inside the border and how frame
looked before the tweaks outside of the border.
Also implemented Clear Viewer Border in compositor, shortcut
it Ctrl-Alt-B.
Reviewers: lukastoenne, jbakker
CC: venomgfx, sebastian_k
Differential Revision: https://developer.blender.org/D582
Suppress warning for now, it's harmless and only happens
with new libpng.
In the future we might try enabling it for non-datatoc-ed
files, but it's really not worth spending lots of time on.
Objects were hidden in "only render" mode if they were duplicators. This is correct in general, but for particles should be disabled by the "show emitter" option.
Simply add an option to render settings to save an EXR cache,
just when the render is finished. Also changed RE_ReadRenderResult() to read
cache instead of temp sample files (those are fully volatile now anyway).
Path to save cached render results is an UserPreferences setting.
Also added 'Reload render' feature to the Image Editor (so one can now re-open a blend,
and in an Image Editor hit ctrl-R to (try to) reload last render from cache).
Reviewers: campbellbarton, sergey
Differential Revision: https://developer.blender.org/D553
