r} [x=0] - The x value of this quaternion. * @param {number} [y=0] - The y value of this quaternion. * @param {number} [z=0] - The z value of this quaternion. * @param {number} [w=1] - The w value of this quaternion. */ constructor( x = 0, y = 0, z = 0, w = 1 ) { /** * This flag can be used for type testing. * * @type {boolean} * @readonly * @default true */ this.isQuaternion = true; this._x = x; this._y = y; this._z = z; this._w = w; } /** * Interpolates between two quaternions via SLERP. This implementation assumes the * quaternion data are managed in flat arrays. * * @param {Array} dst - The destination array. * @param {number} dstOffset - An offset into the destination array. * @param {Array} src0 - The source array of the first quaternion. * @param {number} srcOffset0 - An offset into the first source array. * @param {Array} src1 - The source array of the second quaternion. * @param {number} srcOffset1 - An offset into the second source array. * @param {number} t - The interpolation factor. A value in the range `[0,1]` will interpolate. A value outside the range `[0,1]` will extrapolate. * @see {@link Quaternion#slerp} */ static slerpFlat( dst, dstOffset, src0, srcOffset0, src1, srcOffset1, t ) { let x0 = src0[ srcOffset0 + 0 ], y0 = src0[ srcOffset0 + 1 ], z0 = src0[ srcOffset0 + 2 ], w0 = src0[ srcOffset0 + 3 ]; let x1 = src1[ srcOffset1 + 0 ], y1 = src1[ srcOffset1 + 1 ], z1 = src1[ srcOffset1 + 2 ], w1 = src1[ srcOffset1 + 3 ]; if ( w0 !== w1 || x0 !== x1 || y0 !== y1 || z0 !== z1 ) { let dot = x0 * x1 + y0 * y1 + z0 * z1 + w0 * w1; if ( dot < 0 ) { x1 = - x1; y1 = - y1; z1 = - z1; w1 = - w1; dot = - dot; } let s = 1 - t; if ( dot < 0.9995 ) { // slerp const theta = Math.acos( dot ); const sin = Math.sin( theta ); s = Math.sin( s * theta ) / sin; t = Math.sin( t * theta ) / sin; x0 = x0 * s + x1 * t; y0 = y0 * s + y1 * t; z0 = z0 * s + z1 * t; w0 = w0 * s + w1 * t; } else { // for small angles, lerp then normalize x0 = x0 * s + x1 * t; y0 = y0 * s + y1 * t; z0 = z0 * s + z1 * t; w0 = w0 * s + w1 * t; const f = 1 / Math.sqrt( x0 * x0 + y0 * y0 + z0 * z0 + w0 * w0 ); x0 *= f; y0 *= f; z0 *= f; w0 *= f; } } dst[ dstOffset ] = x0; dst[ dstOffset + 1 ] = y0; dst[ dstOffset + 2 ] = z0; dst[ dstOffset + 3 ] = w0; } /** * Multiplies two quaternions. This implementation assumes the quaternion data are managed * in flat arrays. * * @param {Array} dst - The destination array. * @param {number} dstOffset - An offset into the destination array. * @param {Array} src0 - The source array of the first quaternion. * @param {number} srcOffset0 - An offset into the first source array. * @param {Array} src1 - The source array of the second quaternion. * @param {number} srcOffset1 - An offset into the second source array. * @return {Array} The destination array. * @see {@link Quaternion#multiplyQuaternions}. */ static multiplyQuaternionsFlat( dst, dstOffset, src0, srcOffset0, src1, srcOffset1 ) { const x0 = src0[ srcOffset0 ]; const y0 = src0[ srcOffset0 + 1 ]; const z0 = src0[ srcOffset0 + 2 ]; const w0 = src0[ srcOffset0 + 3 ]; const x1 = src1[ srcOffset1 ]; const y1 = src1[ srcOffset1 + 1 ]; const z1 = src1[ srcOffset1 + 2 ]; const w1 = src1[ srcOffset1 + 3 ]; dst[ dstOffset ] = x0 * w1 + w0 * x1 + y0 * z1 - z0 * y1; dst[ dstOffset + 1 ] = y0 * w1 + w0 * y1 + z0 * x1 - x0 * z1; dst[ dstOffset + 2 ] = z0 * w1 + w0 * z1 + x0 * y1 - y0 * x1; dst[ dstOffset + 3 ] = w0 * w1 - x0 * x1 - y0 * y1 - z0 * z1; return dst; } /** * The x value of this quaternion. * * @type {number} * @default 0 */ get x() { return this._x; } set x( value ) { this._x = value; this._onChangeCallback(); } /** * The y value of this quaternion. * * @type {number} * @default 0 */ get y() { return this._y; } set y( value ) { this._y = value; this._onChangeCallback(); } /** * The z value of this quaternion. * * @type {number} * @default 0 */ get z() { return this._z; } set z( value ) { this._z = value; this._onChangeCallback(); } /** * The w value of this quaternion. * * @type {number} * @default 1 */ get w() { return this._w; } set w( value ) { this._w = value; this._onChangeCallback(); } /** * Sets the quaternion components. * * @param {number} x - The x value of this quaternion. * @param {number} y - The y value of this quaternion. * @param {number} z - The z value of this quaternion. * @param {number} w - The w value of this quaternion. * @return {Quaternion} A reference to this quaternion. */ set( x, y, z, w ) { this._x = x; this._y = y;