threejs/examples/jsm/misc/MorphBlendMesh.js

import {
	MathUtils,
	Mesh
} from 'three';

class MorphBlendMesh extends Mesh {

	constructor( geometry, material ) {

		super( geometry, material );

		this.animationsMap = {};
		this.animationsList = [];

		// prepare default animation
		// (all frames played together in 1 second)

		const numFrames = Object.keys( this.morphTargetDictionary ).length;

		const name = '__default';

		const startFrame = 0;
		const endFrame = numFrames - 1;

		const fps = numFrames / 1;

		this.createAnimation( name, startFrame, endFrame, fps );
		this.setAnimationWeight( name, 1 );

	}

	createAnimation( name, start, end, fps ) {

		const animation = {

			start: start,
			end: end,

			length: end - start + 1,

			fps: fps,
			duration: ( end - start ) / fps,

			lastFrame: 0,
			currentFrame: 0,

			active: false,

			time: 0,
			direction: 1,
			weight: 1,

			directionBackwards: false,
			mirroredLoop: false

		};

		this.animationsMap[ name ] = animation;
		this.animationsList.push( animation );

	}

	autoCreateAnimations( fps ) {

		const pattern = /([a-z]+)_?(\d+)/i;

		let firstAnimation;

		const frameRanges = {};

		let i = 0;

		for ( const key in this.morphTargetDictionary ) {

			const chunks = key.match( pattern );

			if ( chunks && chunks.length > 1 ) {

				const name = chunks[ 1 ];

				if ( ! frameRanges[ name ] ) frameRanges[ name ] = { start: Infinity, end: - Infinity };

				const range = frameRanges[ name ];

				if ( i < range.start ) range.start = i;
				if ( i > range.end ) range.end = i;

				if ( ! firstAnimation ) firstAnimation = name;

			}

			i ++;

		}

		for ( const name in frameRanges ) {

			const range = frameRanges[ name ];
			this.createAnimation( name, range.start, range.end, fps );

		}

		this.firstAnimation = firstAnimation;

	}

	setAnimationDirectionForward( name ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.direction = 1;
			animation.directionBackwards = false;

		}

	}

	setAnimationDirectionBackward( name ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.direction = - 1;
			animation.directionBackwards = true;

		}

	}

	setAnimationFPS( name, fps ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.fps = fps;
			animation.duration = ( animation.end - animation.start ) / animation.fps;

		}

	}

	setAnimationDuration( name, duration ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.duration = duration;
			animation.fps = ( animation.end - animation.start ) / animation.duration;

		}

	}

	setAnimationWeight( name, weight ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.weight = weight;

		}

	}

	setAnimationTime( name, time ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.time = time;

		}

	}

	getAnimationTime( name ) {

		let time = 0;

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			time = animation.time;

		}

		return time;

	}

	getAnimationDuration( name ) {

		let duration = - 1;

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			duration = animation.duration;

		}

		return duration;

	}

	playAnimation( name ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.time = 0;
			animation.active = true;

		} else {

			console.warn( 'THREE.MorphBlendMesh: animation[' + name + '] undefined in .playAnimation()' );

		}

	}

	stopAnimation( name ) {

		const animation = this.animationsMap[ name ];

		if ( animation ) {

			animation.active = false;

		}

	}

	update( delta ) {

		for ( let i = 0, il = this.animationsList.length; i < il; i ++ ) {

			const animation = this.animationsList[ i ];

			if ( ! animation.active ) continue;

			const frameTime = animation.duration / animation.length;

			animation.time += animation.direction * delta;

			if ( animation.mirroredLoop ) {

				if ( animation.time > animation.duration || animation.time < 0 ) {

					animation.direction *= - 1;

					if ( animation.time > animation.duration ) {

						animation.time = animation.duration;
						animation.directionBackwards = true;

					}

					if ( animation.time < 0 ) {

						animation.time = 0;
						animation.directionBackwards = false;

					}

				}

			} else {

				animation.time = animation.time % animation.duration;

				if ( animation.time < 0 ) animation.time += animation.duration;

			}

			const keyframe = animation.start + MathUtils.clamp( Math.floor( animation.time / frameTime ), 0, animation.length - 1 );
			const weight = animation.weight;

			if ( keyframe !== animation.currentFrame ) {

				this.morphTargetInfluences[ animation.lastFrame ] = 0;
				this.morphTargetInfluences[ animation.currentFrame ] = 1 * weight;

				this.morphTargetInfluences[ keyframe ] = 0;

				animation.lastFrame = animation.currentFrame;
				animation.currentFrame = keyframe;

			}

			let mix = ( animation.time % frameTime ) / frameTime;

			if ( animation.directionBackwards ) mix = 1 - mix;

			if ( animation.currentFrame !== animation.lastFrame ) {

				this.morphTargetInfluences[ animation.currentFrame ] = mix * weight;
				this.morphTargetInfluences[ animation.lastFrame ] = ( 1 - mix ) * weight;

			} else {

				this.morphTargetInfluences[ animation.currentFrame ] = weight;

			}

		}

	}

}

export { MorphBlendMesh };