Fix issue described in T87678, which was partially a bug and partially
change in intended(at least as far as I can tell) behaior.
Function `evaluate_seq_frame_gen` that was partially responsible for
filtering strips in stack for rendering wasn't working correctly.
Intended functionality seems to be removing all effect inputs from stack
as it is unlikely that user would want these to be blended in. However
there was logic to exclude effects placed into same input, which because
of weak implementation caused, that any effect input, that is effect as
well will be considered to be part of stack to be blended in.
This bug was apparently used to produce effects like glow over original
image.
Even though this is originally unintended, I have kept this logic, but
I have made it explicit.
Another change is request made in T87678 to make it possible to keep
effect inputs as part of stack when they are placed above the effect,
which would imply that blending is intended. This change is again
explicitly defined.
Whole implementation has been refactored, so logic is consolidated
and code should be as explicit as possible and more readable.
`must_render_strip function` may be still quite hard to read, not sure
if I can make it nicer.
Last change is for remove gaps feature code - it used same rendering
code, which may be reason why its logic was split in first place.
Now it uses sequencer iterator, which will definitely be faster than
original code, but I could have used `LISTBASE_FOREACH` in this case.
Reviewed By: sergey
Differential Revision: https://developer.blender.org/D11301
Python API function Sequence.move_to_meta() did delete effect chain
when strip with effects was moved.
Use iterator API to query effect strips and move whole chain to meta.
Reviewed By: sergey
Differential Revision: https://developer.blender.org/D11206
This iterator design provides means to create simple and flexible API
to query and work with collection of strips. It should be used in cases
when conditions require multiple stages of recursive iteration of all
strips or similar complex scenarios.
Quick API overview:
Basic queries are standalone functions that return SeqCollection
Use SEQ_collection_create() and SEQ_collection_free() to construct
such query functions.
Use these functions to get strips of known conditions, like selected
strips, movie strips, muted strips and so on.
Use SEQ_reference_query() when querying strips with relation to
some reference strip. For example to get its effects, strips that have
same type or use same input file and so on.
These aren't standalone functions because often you need to query strips
relative to each strip in collection.
Use SEQ_collection_expand() to query strips relative to each strip
in collection. These will be merged to original collection.
Use SEQ_collection_merge() to merge 2 collections
To iterate collection elements use macro SEQ_ITERATOR_FOREACH()
This API is quite specific, but I think it is best suited for tasks
that are usualy solved in sequencer codebase.
Old sequencer iterator has been completely removed.
SEQ_ALL_BEGIN and SEQ_ALL_END macros re-use new iterator design.
As initial use for this iterator select_grouped_effect_link()
function has been rewritten. It was not only broken, but also it used
DNA fields to aid iterating strips.
Reviewed By: sergey
Differential Revision: https://developer.blender.org/D10337
`SEQ_recursive_apply` and `SEQ_seqbase_recursive_apply` were incorrectly
refactored into `iterator.c` file, but they aren't part and don't use
sequencer iterator.
Functions are moved to `utils.c` file.
Use LISTBASE_FOREACH instead.
SEQ_CURRENT_BEGIN did null checks, so now these must be explicit.
Reviewed By: campbellbarton
Differential Revision: https://developer.blender.org/D10823
