132 lines
4.6 KiB
JavaScript
132 lines
4.6 KiB
JavaScript
import * as THREE from 'three';
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import { FBXLoader } from 'three/addons/loaders/FBXLoader.js';
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import { mixamoVRMRigMap } from './mixamoVRMRigMap.js';
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/**
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* Load Mixamo animation, convert for three-vrm use, and return it.
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*
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* @param {string} url A url of mixamo animation data
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* @param {VRM} vrm A target VRM
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* @param {Object} options Optional settings
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* @param {boolean} options.stripRootMotion - If true, removes X/Z translation from hips (keeps Y for foot contact)
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* @param {boolean} options.makeAdditive - If true, makes the clip additive (subtracts first frame)
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* @returns {Promise<THREE.AnimationClip>} The converted AnimationClip
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*/
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export function loadMixamoAnimation( url, vrm, options = {} ) {
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const { stripRootMotion = false, makeAdditive = false, clipName = null } = options;
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const loader = new FBXLoader(); // A loader which loads FBX
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return loader.loadAsync( url ).then( ( asset ) => {
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const clip = THREE.AnimationClip.findByName( asset.animations, 'mixamo.com' ); // extract the AnimationClip
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const tracks = []; // KeyframeTracks compatible with VRM will be added here
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const restRotationInverse = new THREE.Quaternion();
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const parentRestWorldRotation = new THREE.Quaternion();
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const _quatA = new THREE.Quaternion();
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const _vec3 = new THREE.Vector3();
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// Adjust with reference to hips height.
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const motionHipsHeight = asset.getObjectByName( 'mixamorigHips' ).position.y;
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const vrmHipsHeight = vrm.humanoid.normalizedRestPose.hips.position[ 1 ];
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const hipsPositionScale = vrmHipsHeight / motionHipsHeight;
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// Get the hips bone name in VRM for root motion stripping
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const hipsVrmNodeName = vrm.humanoid?.getNormalizedBoneNode( 'hips' )?.name;
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clip.tracks.forEach( ( track ) => {
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// Convert each tracks for VRM use, and push to `tracks`
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const trackSplitted = track.name.split( '.' );
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const mixamoRigName = trackSplitted[ 0 ];
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const vrmBoneName = mixamoVRMRigMap[ mixamoRigName ];
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const vrmNodeName = vrm.humanoid?.getNormalizedBoneNode( vrmBoneName )?.name;
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const mixamoRigNode = asset.getObjectByName( mixamoRigName );
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if ( vrmNodeName != null ) {
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const propertyName = trackSplitted[ 1 ];
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// Store rotations of rest-pose.
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mixamoRigNode.getWorldQuaternion( restRotationInverse ).invert();
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mixamoRigNode.parent.getWorldQuaternion( parentRestWorldRotation );
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if ( track instanceof THREE.QuaternionKeyframeTrack ) {
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// Retarget rotation of mixamoRig to NormalizedBone.
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for ( let i = 0; i < track.values.length; i += 4 ) {
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const flatQuaternion = track.values.slice( i, i + 4 );
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_quatA.fromArray( flatQuaternion );
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_quatA
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.premultiply( parentRestWorldRotation )
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.multiply( restRotationInverse );
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_quatA.toArray( flatQuaternion );
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flatQuaternion.forEach( ( v, index ) => {
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track.values[ index + i ] = v;
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} );
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}
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tracks.push(
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new THREE.QuaternionKeyframeTrack(
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`${vrmNodeName}.${propertyName}`,
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track.times,
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track.values.map( ( v, i ) => ( vrm.meta?.metaVersion === '0' && i % 2 === 0 ? - v : v ) ),
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),
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);
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} else if ( track instanceof THREE.VectorKeyframeTrack ) {
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let value = track.values.map( ( v, i ) => ( vrm.meta?.metaVersion === '0' && i % 3 !== 1 ? - v : v ) * hipsPositionScale );
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// Strip root motion (X/Z translation) from hips if requested
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// This keeps the character in place while the movement controller handles actual translation
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if ( stripRootMotion && vrmBoneName === 'hips' && propertyName === 'position' ) {
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// Get the first frame's X and Z values to use as baseline
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const baseX = value[ 0 ];
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const baseZ = value[ 2 ];
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// Zero out X and Z translation, keep Y for vertical motion (jumping, bobbing)
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value = value.map( ( v, i ) => {
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const component = i % 3;
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if ( component === 0 ) return 0; // X - zero out horizontal
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if ( component === 2 ) return 0; // Z - zero out horizontal
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return v; // Y - keep vertical motion
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} );
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console.log( `🦶 Stripped root motion from hips position track` );
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}
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tracks.push( new THREE.VectorKeyframeTrack( `${vrmNodeName}.${propertyName}`, track.times, value ) );
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}
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}
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} );
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// Use custom name or generate from URL
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const animationName = clipName || url.split('/').pop().replace('.fbx', '').replace('.FBX', '');
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let resultClip = new THREE.AnimationClip( animationName, clip.duration, tracks );
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// Make the clip additive if requested (for layered animations)
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if ( makeAdditive ) {
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THREE.AnimationUtils.makeClipAdditive( resultClip );
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console.log( `➕ Made clip additive: ${animationName}` );
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}
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return resultClip;
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} );
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}
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