Fix #107030: return accurate action frame ranges from the Python API #112709

Nathan Vegdahl · 2023-09-22T10:44:09+02:00

Nathan Vegdahl commented

2023-09-22 10:44:09 +02:00

This changes the action.frame_range Python API to return an accurate
frame range for actions. Specifically, it was previously special-cased
to return a range with length 1 whenever the length was actually 0. This
led to a bizarre situation where a real frame range of [0.0, 0.2] would
return that range as-is, but a real frame range of [0.0, 0.0] would
instead return a range of [0.0, 1.0].

The new behavior simply always returns the real frame range.

The reason for the previous behavior was obscure: the relevant code was
also used internally in Blender's NLA system, and returning a zero-length
range could result in NLA strips getting infinite scale. The code is now
separated out appropriately so that the NLA system still gets the
non-zero-length range, while the Python API for actions returns the real
range.

This changes the `action.frame_range` Python API to return an accurate frame range for actions. Specifically, it was previously special-cased to return a range with length 1 whenever the length was actually 0. This led to a bizarre situation where a real frame range of `[0.0, 0.2]` would return that range as-is, but a real frame range of `[0.0, 0.0]` would instead return a range of `[0.0, 1.0]`. The new behavior simply always returns the real frame range. The reason for the previous behavior was obscure: the relevant code was also used internally in Blender's NLA system, and returning a zero-length range could result in NLA strips getting infinite scale. The code is now separated out appropriately so that the NLA system still gets the non-zero-length range, while the Python API for actions returns the real range.

Nathan Vegdahl added 1 commit 2023-09-22 10:44:20 +02:00

WIP: Fix #107030 : compute accurate frame ranges for actions 90b3ddf3b0

Nathan Vegdahl added 1 commit 2023-09-26 14:21:15 +02:00

Reinstate the ensure-non-zero logic where needed in the NLA code 1368dbfc94

Nathan Vegdahl added 1 commit 2023-09-26 15:51:50 +02:00

Replace additional ensure-non-zero inline logic with the new functions 7fd5f66da0

Nathan Vegdahl added 1 commit 2023-09-26 16:14:16 +02:00

Change nonzero length get function to take a pointer to the strip ed8b62d23f

Nathan Vegdahl changed title from ~~WIP: Fix #107030: compute accurate frame ranges for actions~~ to Fix #107030: compute accurate frame ranges for actions

2023-09-26 16:22:21 +02:00

Nathan Vegdahl changed title from ~~Fix #107030: compute accurate frame ranges for actions~~ to Fix #107030: return accurate action frame ranges from the Python API

2023-09-26 16:36:33 +02:00

Sybren A. Stüvel requested changes 2023-09-26 16:44:27 +02:00

Sybren A. Stüvel left a comment

This feels a lot saner than the old whack-a-mole.

This might also be a good time to add a unit test for at least the BKE_action_frame_range_calc(), BKE_nla_clip_length_get_nonzero(), and BKE_nla_clip_length_ensure_nonzero() functions. Shouldn't be too much work, and it'll protect us a bit from future accidental alterations.

This feels a lot saner than the old whack-a-mole. This might also be a good time to add a unit test for at least the `BKE_action_frame_range_calc()`, `BKE_nla_clip_length_get_nonzero()`, and `BKE_nla_clip_length_ensure_nonzero()` functions. Shouldn't be too much work, and it'll protect us a bit from future accidental alterations.

👍 1

source/blender/blenkernel/intern/nla.cc Outdated

						
				@ -449,0 +451,4 @@

				  if (strip->actend <= strip->actstart) {

				    return 1.0f;

				  }

				  else {

Sybren A. Stüvel commented

2023-09-26 16:40:59 +02:00

Code style: no else after return.

Code style: no `else` after `return`.

nathanvegdahl marked this conversation as resolved

Nathan Vegdahl added 1 commit 2023-09-26 17:01:13 +02:00

Address review comments. 1e45a98cf7

Nathan Vegdahl added 1 commit 2023-09-26 18:04:52 +02:00

Add unit tests. b8f9542024

Sybren A. Stüvel approved these changes 2023-09-26 18:17:18 +02:00

Sybren A. Stüvel left a comment

Looking good!

Nathan Vegdahl merged commit 49eab72141 into main

2023-09-26 18:19:04 +02:00

Nathan Vegdahl referenced this issue from a commit

2023-09-26 18:19:06 +02:00

Fix #107030: return accurate action frame ranges from the Python API

Nathan Vegdahl deleted branch fix_107030_action_frame_range

2023-09-26 18:19:08 +02:00

Colin Basnett referenced this issue from a commit

2023-09-27 07:30:23 +02:00

Fix #107030: return accurate action frame ranges from the Python API

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Fix #107030: return accurate action frame ranges from the Python API #112709