<!-- NEW5 — TEST 5 · THE BEND AT THE HEART · part 224 -->
 interpolation type of this keyframe track.
 *
 * @type {(InterpolateLinear|InterpolateDiscrete|InterpolateSmooth|InterpolateBezier)}
 * @default InterpolateLinear
 */
KeyframeTrack.prototype.DefaultInterpolation = InterpolateLinear;

/**
 * A track for boolean keyframe values.
 *
 * @augments KeyframeTrack
 */
class BooleanKeyframeTrack extends KeyframeTrack {

	/**
	 * Constructs a new boolean keyframe track.
	 *
	 * This keyframe track type has no `interpolation` parameter because the
	 * interpolation is always discrete.
	 *
	 * @param {string} name - The keyframe track's name.
	 * @param {Array<number>} times - A list of keyframe times.
	 * @param {Array<boolean>} values - A list of keyframe values.
	 */
	constructor( name, times, values ) {

		super( name, times, values );

	}

}

/**
 * The value type name.
 *
 * @type {string}
 * @default 'bool'
 */
BooleanKeyframeTrack.prototype.ValueTypeName = 'bool';

/**
 * The value buffer type of this keyframe track.
 *
 * @type {TypedArray|Array}
 * @default Array.constructor
 */
BooleanKeyframeTrack.prototype.ValueBufferType = Array;

/**
 * The default interpolation type of this keyframe track.
 *
 * @type {(InterpolateLinear|InterpolateDiscrete|InterpolateSmooth)}
 * @default InterpolateDiscrete
 */
BooleanKeyframeTrack.prototype.DefaultInterpolation = InterpolateDiscrete;
BooleanKeyframeTrack.prototype.InterpolantFactoryMethodLinear = undefined;
BooleanKeyframeTrack.prototype.InterpolantFactoryMethodSmooth = undefined;

/**
 * A track for color keyframe values.
 *
 * @augments KeyframeTrack
 */
class ColorKeyframeTrack extends KeyframeTrack {

	/**
	 * Constructs a new color keyframe track.
	 *
	 * @param {string} name - The keyframe track's name.
	 * @param {Array<number>} times - A list of keyframe times.
	 * @param {Array<number>} values - A list of keyframe values.
	 * @param {(InterpolateLinear|InterpolateDiscrete|InterpolateSmooth)} [interpolation] - The interpolation type.
	 */
	constructor( name, times, values, interpolation ) {

		super( name, times, values, interpolation );

	}

}

/**
 * The value type name.
 *
 * @type {string}
 * @default 'color'
 */
ColorKeyframeTrack.prototype.ValueTypeName = 'color';

/**
 * A track for numeric keyframe values.
 *
 * @augments KeyframeTrack
 */
class NumberKeyframeTrack extends KeyframeTrack {

	/**
	 * Constructs a new number keyframe track.
	 *
	 * @param {string} name - The keyframe track's name.
	 * @param {Array<number>} times - A list of keyframe times.
	 * @param {Array<number>} values - A list of keyframe values.
	 * @param {(InterpolateLinear|InterpolateDiscrete|InterpolateSmooth)} [interpolation] - The interpolation type.
	 */
	constructor( name, times, values, interpolation ) {

		super( name, times, values, interpolation );

	}

}

/**
 * The value type name.
 *
 * @type {string}
 * @default 'number'
 */
NumberKeyframeTrack.prototype.ValueTypeName = 'number';

/**
 * Spherical linear unit quaternion interpolant.
 *
 * @augments Interpolant
 */
class QuaternionLinearInterpolant extends Interpolant {

	/**
	 * Constructs a new SLERP interpolant.
	 *
	 * @param {TypedArray} parameterPositions - The parameter positions hold the interpolation factors.
	 * @param {TypedArray} sampleValues - The sample values.
	 * @param {number} sampleSize - The sample size
	 * @param {TypedArray} [resultBuffer] - The result buffer.
	 */
	constructor( parameterPositions, sampleValues, sampleSize, resultBuffer ) {

		super( parameterPositions, sampleValues, sampleSize, resultBuffer );

	}

	interpolate_( i1, t0, t, t1 ) {

		const result = this.resultBuffer,
			values = this.sampleValues,
			stride = this.valueSize,

			alpha = ( t - t0 ) / ( t1 - t0 );

		let offset = i1 * stride;

		for ( let end = offset + stride; offset !== end; offset += 4 ) {

			Quaternion.slerpFlat( result, 0, values, offset - stride, values, offset, alpha );

		}

		return result;

	}

}

/**
 * A track for Quaternion keyframe values.
 *
 * @augments KeyframeTrack
 */
class QuaternionKeyframeTrack extends KeyframeTrack {

	/**
	 * Constructs a new Quaternion keyframe track.
	 *
	 * @param {string} name - The keyframe track's name.
	 * @param {Array<number>} times - A list of keyframe times.
	 * @param {Array<number>} values - A list of keyframe values.
	 * @param {(InterpolateLinear|InterpolateDiscrete|InterpolateSmooth)} [interpolation] - The interpolation type.
	 */
	constructor( name, times, values, interpolation ) {

		super( name, times, values, interpolation );

	}

	/**
	 * Overwritten so the method returns Quaternion based interpolant.
	 *
	 * @static
	 * @param {TypedArray} [result] - The result buffer.
	 * @return {QuaternionLinearInterpolant} The new interpolant.
	 */
	InterpolantFactoryMethodLinear( result ) {

		return new QuaternionLinearInterpolant( this.times, this.values, this.getValueSize(), result );

	}

}

/**
 * The value type name.
 *
 * @type {string}
 * @defa