Mesh .updateMorphTargets(): Added BufferGeometry support

[Mugen87]

see #11277

[looeee]

Would it be a good idea to make sure the name is always a string? Or do you think it doesn't matter?

[Mugen87]

Yeah, maybe it's cleaner if we always ensure strings. I'll change this 👍

[looeee]

Might need to make some updates to PropertyBindings.js too, as it has a special case for morphTargetInfluences where it specifically looks for a `morphTargets' property on the geometry. Here...

[Mugen87]

I need to debug this in order to understand the code. We should currently run into this log here because morphTargets is undefined. I actually didn't see this message in my tests.

[looeee]

By the way I had a search through code in /src and /examples/js and couldn't find any other places where this will cause an issue. Although I may have missed something of course!

[Mugen87]

@looeee It is important, that the name of the morph attribute matches the name of the KeyframeTrack.

const morphAttribute = new THREE.BufferAttribute( morphPositions, 3 );
morphAttribute.name = 'animation001';
geometry.morphAttributes.position.push( morphAttribute );

Have a look at the following nomenclature propertyName[morphAttributeName/morphTargetName].

const track = new THREE.NumberKeyframeTrack( '.morphTargetInfluences[animation001]', [ 0.0, 5 ], [ 0.0, 1.0 ], THREE.InterpolateSmooth );

morphTargetInfluences can be affected by not just a single track of morph target data. A more complex animation consists of many morph targets. The suffix of a name is normally consecutively numbered to represent the order (animation001, animation002, animation003 ...). This information is used by PropertyBinding. The last PR should added support for BufferGeometry based morphTargets in PropertyBinding. But this change needs a review by @tschw

[looeee]

So, the name parameter in KeyframeTrack will be slightly different depending on whether it's targeting a morphTarget or a morphAttribute?

[Mugen87]

No, they are identical. Normally, clips would not be created manually but like this:

// setup clips with THREE.AnimationClip
// we assume geometry.morphAttributes was created by a loader

const clips = THREE.AnimationClip.CreateClipsFromMorphTargetSequences( geometry.morphAttributes.position, 10 );
const clip = THREE.AnimationClip.findByName( clips, 'animation' );

const mixer = new THREE.AnimationMixer( mesh );
const animationAction = mixer.clipAction( clip );

[Mugen87]

Check out the implementation of AnimationClip .CreateClipsFromMorphTargetSequences() to see, how the naming convention works. There are some helpful comments in the code.

[mrdoob]

Should we also remove the hack in MMDLoader? #11277 (comment)

/cc @takahirox

[takahirox]

I haven't followed the entire discussion yet but I suppose
we can remove if facial morphing animation of webgl_loader_mmd* examples work fine without the hack.

[mrdoob]

Thanks!