import {
AnimationClip,
Bone,
FileLoader,
Loader,
Quaternion,
QuaternionKeyframeTrack,
Skeleton,
Vector3,
VectorKeyframeTrack
} from 'three';
/**
* Description: reads BVH files and outputs a single Skeleton and an AnimationClip
*
* Currently only supports bvh files containing a single root.
*
*/
class BVHLoader extends Loader {
constructor( manager ) {
super( manager );
this.animateBonePositions = true;
this.animateBoneRotations = true;
}
load( url, onLoad, onProgress, onError ) {
const scope = this;
const loader = new FileLoader( scope.manager );
loader.setPath( scope.path );
loader.setRequestHeader( scope.requestHeader );
loader.setWithCredentials( scope.withCredentials );
loader.load( url, function ( text ) {
try {
onLoad( scope.parse( text ) );
} catch ( e ) {
if ( onError ) {
onError( e );
} else {
console.error( e );
}
scope.manager.itemError( url );
}
}, onProgress, onError );
}
parse( text ) {
/*
reads a string array (lines) from a BVH file
and outputs a skeleton structure including motion data
returns thee root node:
{ name: '', channels: [], children: [] }
*/
function readBvh( lines ) {
// read model structure
if ( nextLine( lines ) !== 'HIERARCHY' ) {
console.error( 'THREE.BVHLoader: HIERARCHY expected.' );
}
const list = []; // collects flat array of all bones
const root = readNode( lines, nextLine( lines ), list );
// read motion data
if ( nextLine( lines ) !== 'MOTION' ) {
console.error( 'THREE.BVHLoader: MOTION expected.' );
}
// number of frames
let tokens = nextLine( lines ).split( /[\s]+/ );
const numFrames = parseInt( tokens[ 1 ] );
if ( isNaN( numFrames ) ) {
console.error( 'THREE.BVHLoader: Failed to read number of frames.' );
}
// frame time
tokens = nextLine( lines ).split( /[\s]+/ );
const frameTime = parseFloat( tokens[ 2 ] );
if ( isNaN( frameTime ) ) {
console.error( 'THREE.BVHLoader: Failed to read frame time.' );
}
// read frame data line by line
for ( let i = 0; i < numFrames; i ++ ) {
tokens = nextLine( lines ).split( /[\s]+/ );
readFrameData( tokens, i * frameTime, root );
}
return list;
}
/*
Recursively reads data from a single frame into the bone hierarchy.
The passed bone hierarchy has to be structured in the same order as the BVH file.
keyframe data is stored in bone.frames.
- data: splitted string array (frame values), values are shift()ed so
this should be empty after parsing the whole hierarchy.
- frameTime: playback time for this keyframe.
- bone: the bone to read frame data from.
*/
function readFrameData( data, frameTime, bone ) {
// end sites have no motion data
if ( bone.type === 'ENDSITE' ) return;
// add keyframe
const keyframe = {
time: frameTime,
position: new Vector3(),
rotation: new Quaternion()
};
bone.frames.push( keyframe );
const quat = new Quaternion();
const vx = new Vector3( 1, 0, 0 );
const vy = new Vector3( 0, 1, 0 );
const vz = new Vector3( 0, 0, 1 );
// parse values for each channel in node
for ( let i = 0; i < bone.channels.length; i ++ ) {
switch ( bone.channels[ i ] ) {
case 'Xposition':
keyframe.position.x = parseFloat( data.shift().trim() );
break;
case 'Yposition':
keyframe.position.y = parseFloat( data.shift().trim() );
break;
case 'Zposition':
keyframe.position.z = parseFloat( data.shift().trim() );
break;
case 'Xrotation':
quat.setFromAxisAngle( vx, parseFloat( data.shift().trim() ) * Math.PI / 180 );
keyframe.rotation.multiply( quat );
break;
case 'Yrotation':
quat.setFromAxisAngle( vy, parseFloat( data.shift().trim() ) * Math.PI / 180 );
keyframe.rotation.multiply( quat );
break;
case 'Zrotation':
quat.setFromAxisAngle( vz, parseFloat( data.shift().trim() ) * Math.PI / 180 );
keyframe.rotation.multiply( quat );
break;
default:
console.warn( 'THREE.BVHLoader: Invalid channel type.' );
}
}
// parse child nodes
for ( let i = 0; i < bone.children.length; i ++ ) {
readFrameData( data, frameTime, bone.children[ i ] );
}
}
/*
Recursively parses the HIERACHY section of the BVH file
- lines: all lines of the file. lines are consumed as we go along.
- firstline: line containing the node type and name e.g. 'JOINT hip'
- list: collects a flat list of nodes
returns: a BVH node including children
*/
function readNode( lines, firstline, list ) {
const node = { name: '', type: '', frames: [] };
list.push( node );
// parse node type and name
let tokens = firstline.split( /[\s]+/ );
if ( tokens[ 0 ].toUpperCase() === 'END' && tokens[ 1 ].toUpperCase() === 'SITE' ) {
node.type = 'ENDSITE';
node.name = 'ENDSITE'; // bvh end sites have no name
} else {
node.name = tokens[ 1 ];
node.type = tokens[ 0 ].toUpperCase();
}
if ( nextLine( lines ) !== '{' ) {
console.error( 'THREE.BVHLoader: Expected opening { after type & name' );
}
// parse OFFSET
tokens = nextLine( lines ).split( /[\s]+/ );
if ( tokens[ 0 ] !== 'OFFSET' ) {
console.error( 'THREE.BVHLoader: Expected OFFSET but got: ' + tokens[ 0 ] );
}
if ( tokens.length !== 4 ) {
console.error( 'THREE.BVHLoader: Invalid number of values for OFFSET.' );
}
const offset = new Vector3(
parseFloat( tokens[ 1 ] ),
parseFloat( tokens[ 2 ] ),
parseFloat( tokens[ 3 ] )
);
if ( isNaN( offset.x ) || isNaN( offset.y ) || isNaN( offset.z ) ) {
console.error( 'THREE.BVHLoader: Invalid values of OFFSET.' );
}
node.offset = offset;
// parse CHANNELS definitions
if ( node.type !== 'ENDSITE' ) {
tokens = nextLine( lines ).split( /[\s]+/ );
if ( tokens[ 0 ] !== 'CHANNELS' ) {
console.error( 'THREE.BVHLoader: Expected CHANNELS definition.' );
}
const numChannels = parseInt( tokens[ 1 ] );
node.channels = tokens.splice( 2, numChannels );
node.children = [];
}
// read children
while ( true ) {
const line = nextLine( lines );
if ( line === '}' ) {
return node;
} else {
node.children.push( readNode( lines, line, list ) );
}
}
}
/*
recursively converts the internal bvh node structure to a Bone hierarchy
source: the bvh root node
list: pass an empty array, collects a flat list of all converted THREE.Bones
returns the root Bone
*/
function toTHREEBone( source, list ) {
const bone = new Bone();
list.push( bone );
bone.position.add( source.offset );
bone.name = source.name;
if ( source.type !== 'ENDSITE' ) {
for ( let i = 0; i < source.children.length; i ++ ) {
bone.add( toTHREEBone( source.children[ i ], list ) );
}
}
return bone;
}
/*
builds a AnimationClip from the keyframe data saved in each bone.
bone: bvh root node
returns: a AnimationClip containing position and quaternion tracks
*/
function toTHREEAnimation( bones ) {
const tracks = [];
// create a position and quaternion animation track for each node
for ( let i = 0; i < bones.length; i ++ ) {
const bone = bones[ i ];
if ( bone.type === 'ENDSITE' )
continue;
// track data
const times = [];
const positions = [];
const rotations = [];
for ( let j = 0; j < bone.frames.length; j ++ ) {
const frame = bone.frames[ j ];
times.push( frame.time );
// the animation system animates the position property,
// so we have to add the joint offset to all values
positions.push( frame.position.x + bone.offset.x );
positions.push( frame.position.y + bone.offset.y );
positions.push( frame.position.z + bone.offset.z );
rotations.push( frame.rotation.x );
rotations.push( frame.rotation.y );
rotations.push( frame.rotation.z );
rotations.push( frame.rotation.w );
}
if ( scope.animateBonePositions ) {
tracks.push( new VectorKeyframeTrack( bone.name + '.position', times, positions ) );
}
if ( scope.animateBoneRotations ) {
tracks.push( new QuaternionKeyframeTrack( bone.name + '.quaternion', times, rotations ) );
}
}
return new AnimationClip( 'animation', - 1, tracks );
}
/*
returns the next non-empty line in lines
*/
function nextLine( lines ) {
let line;
// skip empty lines
while ( ( line = lines.shift().trim() ).length === 0 ) { }
return line;
}
const scope = this;
const lines = text.split( /[\r\n]+/g );
const bones = readBvh( lines );
const threeBones = [];
toTHREEBone( bones[ 0 ], threeBones );
const threeClip = toTHREEAnimation( bones );
return {
skeleton: new Skeleton( threeBones ),
clip: threeClip
};
}
}
export { BVHLoader };
