• RuntimesGodot

  • IK and Transform constraints applied after setting a tracks animation to empty.

    anglais

IK and Transform constraints are still being applied after setting a tracks animation to empty.

I'm not sure if I'm running into some edge case I don't understand, or a bug, or what. But I've been troubleshooting this for the better part of a day and could use some insight here.

I have a bone being driven by a SpineBoneNode that essentially 'points' the character's shoulders and head in that direction.
In engine, I've been attempting to animate this character by applying either an idle animation, or a walking animation on track 0, and applying the 'sniper pose' on track 1 which enables an IK constraint, and a couple of transform constraints. If the character, say gets hit, or otherwise move on to another animation, track 1 is set to an empty animation (not added). Track 0 is also often set to a different animation.

In most cases, this works great! But, on a number of occasions, it appears that these constraints are left applied, even though the relevant animation is no longer being played on track 1. Unfortunately this is somewhat difficult to reproduce since it really only occurs when the animations are 'canceled' very quickly after being applied, like within a frame (or maybe on same frame, hard to tell).

Other points of interest:

  • This only occurs when the next animation is longer than one frame.
  • The 'snipers pose' is a single frame, and only has keys for the upper half of the body.
  • I verified that the constraints were applied by fetching their state from the 'animation_state'.
  • SpineBoneNode doesn't always have the proper global_transform in follow mode. Not sure it is relevant here, but I encountered this somewhere along the way.

Any pointers on how to troubleshoot this would be greatly appreciated!

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    It sounds like you are encountering an issue where IK and Transform constraints are not being properly reset when an animation is set to empty. This can happen if the constraints are not explicitly keyed in the empty animation, or if the constraints are not being reset correctly when the animation is cleared.

    Here are a few steps you can take to troubleshoot and potentially resolve this issue:

    1. Ensure Constraints are Keyed in Empty Animation: When you set an animation to empty, make sure that the empty animation explicitly keys the constraints to their default state. This ensures that the constraints are reset when the empty animation is applied.

    2. Check Mix Duration: Ensure that the mix duration is set correctly when transitioning to the empty animation. A mix duration that is too short might not give enough time for the constraints to be reset properly.

    3. Update World Transform: After applying the empty animation, make sure to call skeleton.updateWorldTransform() to ensure that all bones and constraints are updated correctly. This is crucial for ensuring that the skeleton's state is fully updated.

    4. Debugging: Add debug logs to check the state of the constraints before and after applying the empty animation. This can help you identify if the constraints are being reset correctly.

    Here is an example of how you might set an empty animation and update the world transform:

    state.setEmptyAnimation(track, 0);
skeleton.updateWorldTransform();

    If you are using the SpineSprite node in Godot, you can use the following methods to set an empty animation and clear tracks:

    spine_sprite.set_empty_animation(track, mix_duration)
spine_sprite.clear_track(track_id)
spine_sprite.clear_tracks()

    Make sure to call these methods in the correct order and with appropriate parameters to ensure that the constraints are reset properly.

    If the issue persists, consider adding a small delay before setting the empty animation to ensure that the previous animation has enough time to be applied and mixed out correctly.

    yield(get_tree().create_timer(0.1), "timeout")
spine_sprite.set_empty_animation(track, mix_duration)

    This delay can help in cases where animations are canceled very quickly after being applied.

    By following these steps, you should be able to troubleshoot and resolve the issue with constraints not being reset correctly when an animation is set to empty.

    nickswebsite We are sorry to hear that you are experiencing problems. We would like to reproduce your problem, so could you please email us a minimal Godot project that can reproduce the problem?: contact@esotericsoftware.com
    Please include the URL of this forum thread in the email so we know the context. Then we can take a look at what's wrong.

      Sent! I think I found a workaround in the mean time.

      For anybody else who encounters this, it appears to be a problem when the time_scale is set to 0.0. Setting it to something like 0.001, instead of going all the way to 0.0, seems to fix the issue.

      nickswebsite Thank you for sending us a repro project! I was able to reproduce the problem as you described and it seems that setting timescale 0 is the cause as you mentioned. I tried the same code in a different runtime with your skeleton and it mixed out the aim animation correctly, so I think it is probably a bug in spine-godot. I will create an issue ticket to fix this.

        I have created an issue ticket here:
        EsotericSoftware/spine-runtimes2607
        You can subscribe to this issue ticket to receive notifications when there is any progress on this issue.

        5 jours plus tard

        @nickswebsite thanks for the repro. It is indeed a bug in spine-godot, or more specifically spine-cpp. I'm trying to get this fixed up this week. I have to check if the other runtimes are affected as well, which can take a while.