Animation Mix 0

adrian

Hi,

I am working on a mix-and-match Pixel Art character, compiled in parts (head, chest, legs, right hand, left hand...etc) that is animated in 4 directions. Every animation uses stepping mode (it doesn't interpolate any part positions, but utilizes image swaps instead).

I have Animation Mix set to 0, but when my character switches directions quickly, it appears that the parts interpolate to their new positions despite Animation Mix being set to 0. I am trying to prevent this from happening.

I believe this is fixable by keying the first frame of each animation (so that the parts don't interpolate). The issue is that my character plays it's walking animation at the "current animation time" instead of from the beginning. The result is that I would have to key ALL frames, and I'm not sure if this is a best practice.

Does it make sense to key all frames or is there a better way to prevent this type of interpolation?

Regards,
Adrian

Nate

You should not need to set a key every frame. It's hard for me to tell what the issue is. Can you show a GIF or video? Can you reproduce the problem in the Preview view in Spine? Can you show the code being used to change the animations?

MikalDev

I am working with adrian (he's using the C3 Spine plugin), here's the basic code for changing animations:

const state = this.skeletonInfo.state;
const skeleton = this.skeletonInfo.skeleton;

state.setAnimation(0, this.animationName, loop);                

state.tracks[0].listener = {
        complete: (trackEntry, count) => {
            this.completeAnimationName = this.animationName;
            this.Trigger(C3.Plugins.Gritsenko_Spine.Cnds.OnAnimationFinished);
            this.Trigger(C3.Plugins.Gritsenko_Spine.Cnds.OnAnyAnimationFinished);
        },
        event: (trackIndex, event) => {
            this.completeEventName = event.data.name;
            this.Trigger(C3.Plugins.Gritsenko_Spine.Cnds.OnEvent);
        }
    };
state.apply(skeleton);

Nate

Thanks. Is the AnimationStateData defaultMix set to zero?

Don't forget my other questions. 🙂

adrian

Hi Nate,

Please see the attached GIF for some of the animations in Spine preview mode with animation mix set to 0. This looks fine.

The interpolation however can be seen at a few times in the following gameplay video: https://imgur.com/a/eFDBQ7t
The gameplay video might need to be downloaded and scrubbed. I noticed the issue first between the 5.5 - 6s mark.

Here are a few freeze frames from the video to show help illustrate:

Note: Not to confuse you - but in the video my character has 2 right arms and 2 shields (odd I know), one is for a shield holding animation I was working on, so this was intended. In the video I would focus on the weapon and shield located on the characters back - it's the clearest way to see the interpolation happening between animations, although you may notice it does happen to body parts too.

The defaultMix is set to 0 in the C3 runtime (hopefully Mikal can clarify if this is the AnimationStateData defaultMix).

Please let me know if you have any more questions and thank you Mikal for the code snippet, you've been a huge help 🙂

Thanks Nate,
Adrian

MikalDev

Yes, if the C3 project sets the default mix property to 0, the C3 plugin will set AnimationStateData.defaultMix to 0.

Here's the relevant part of the initialization of an instance:

let stateData = new spine.AnimationStateData(this._sdkType._skeletonData);
stateData.defaultMix = this.defaultMix;

var state = new spine.AnimationState(stateData);
state.setAnimation(0, animationName, true);

Nate

Thanks for the clarification. Sometimes a similar problem can happen where you change the animation but don't apply it, so the new animation is not seen until the next frame. It appears that you do apply the animation. Do you also call Skeleton updateWorldTransform after applying the animation but before it is next drawn? When the animation is applied it applies all the timelines which likely set attachments on some slots and manipulate the local transforms of some bones. Drawing uses the world transforms, so you need Skeleton updateWorldTransform to compute the world transforms after the local transforms are modified. This could explain what you see: you see the attachment changes that the animation made, but you don't see the changes it made to the bone transforms.

MikalDev

Nate - the code I posted above was for initialization. Later on it's applied.

In the first code snippet I showed in the thread, this is where I change animation and it does include a state.apply().

However, the updateWorldTransform may not be done before the next draw, there could be a hazard window between the next draw and when I advance delta time of the animation based on engine tick and apply updateWorldTransform. Thanks for the idea!

adrian

Nate - this worked great!

Mikal has put the fix in skeleton.updateWorldTransform(); after state.update and that did the trick.

Thank you so much!
Adrian

Nate

Great! Glad we figured it out. 🙂