/**
 * Copy the values from one vec4 to another
 *
 * @param {vec4} out the receiving vector
 * @param {vec4} a the source vector
 * @returns {vec4} out
 */
export declare function copy(out: any, a: any): any;
/**
 * Set the components of a vec4 to the given values
 *
 * @param {vec4} out the receiving vector
 * @param {Number} x X component
 * @param {Number} y Y component
 * @param {Number} z Z component
 * @param {Number} w W component
 * @returns {vec4} out
 */
export declare function set(out: any, x: any, y: any, z: any, w: any): any;
/**
 * Adds two vec4's
 *
 * @param {vec4} out the receiving vector
 * @param {vec4} a the first operand
 * @param {vec4} b the second operand
 * @returns {vec4} out
 */
export declare function add(out: any, a: any, b: any): any;
/**
 * Scales a vec4 by a scalar number
 *
 * @param {vec4} out the receiving vector
 * @param {vec4} a the vector to scale
 * @param {Number} b amount to scale the vector by
 * @returns {vec4} out
 */
export declare function scale(out: any, a: any, b: any): any;
/**
 * Calculates the length of a vec4
 *
 * @param {vec4} a vector to calculate length of
 * @returns {Number} length of a
 */
export declare function length(a: any): number;
/**
 * Normalize a vec4
 *
 * @param {vec4} out the receiving vector
 * @param {vec4} a vector to normalize
 * @returns {vec4} out
 */
export declare function normalize(out: any, a: any): any;
/**
 * Calculates the dot product of two vec4's
 *
 * @param {vec4} a the first operand
 * @param {vec4} b the second operand
 * @returns {Number} dot product of a and b
 */
export declare function dot(a: any, b: any): number;
/**
 * Performs a linear interpolation between two vec4's
 *
 * @param {vec4} out the receiving vector
 * @param {vec4} a the first operand
 * @param {vec4} b the second operand
 * @param {Number} t interpolation amount between the two inputs
 * @returns {vec4} out
 */
export declare function lerp(out: any, a: any, b: any, t: any): any;