shgroup_instance_alpha was getting a color[4] but would only use the
alpha defined upon creation of the shading group.
This was very limiting since it wouldn't allow for different instances
to have different alpha values.
Patch made with Clément Foucault (he made the code of it, while I fixed
all the parts of the code that were relying on shgroup_instance_alpha.
This removes code duplication and put an end to the old "create at request"
batch creation.
Also it uses the same vbo as the uv layer used for shading. Reducing VRAM
usage.
Also fixes the modified uv display in uv edit mode.
This is in order to allow more spaces to have their batches created at the
same time and sharing the batches.
This is part of the effort fo making the drawing code more optimized. This
commit however should not introduce any difference.
This commit bypass the aspect ratio correction for angle stretch display
but this should be fixed in the next commit.
This makes it more future proof and remove baked id offset inside the vbos.
Instead we add the offset as a uniform. This makes it possible to reuse
the vbos instead of discarding them all the time.
Also using batch request may reduce batches creation time.
TH_BACK was being used when drawing the 3D view even though
there was no way to set the color in the preferences.
The color was zero'd when moving to the new 2.8x theme.
Having both gradient and background colors was confusing,
especially having to use 'TH_HIGH_GRAD' for the 3D view, 'TH_BACK' for
other views.
Move the background color back to 'TH_BACK', 'TH_BACK_GRAD' is used
when gradients are enabled.
RNA is unchanged so presets don't need updating.
Object visibility is now handled by the depsgraph iterator, but this API
was incomplete as it made no distinction for visibility of the object itself,
particles and generated instances.
The depsgraph iterator API now includes information about which part of the
object is visible, and this is used by Cycles to replace the old custom logic.
Cycles and EEVEE visibility should now be consistent, which unfortunately does
means some subtle compatibility breakage for both.
Fixes T58956, T58202, T59284.
Differential Revision: https://developer.blender.org/D4109
this was working for object/collection display/render but lattice was
not taken into account for non object/collection display/render types
(halo, axis, cross, circle, ...)
Reviewers: sergey, brecht
Maniphest Tasks: T59484
Differential Revision: https://developer.blender.org/D4096
