copy( source ) {

		this.name = source.name;
		this.usage = source.usage;

		const uniformsSource = source.uniforms;

		this.uniforms.length = 0;

		for ( let i = 0, l = uniformsSource.length; i < l; i ++ ) {

			const uniforms = Array.isArray( uniformsSource[ i ] ) ? uniformsSource[ i ] : [ uniformsSource[ i ] ];

			for ( let j = 0; j < uniforms.length; j ++ ) {

				this.uniforms.push( uniforms[ j ].clone() );

			}

		}

		return this;

	}
Copies the values of the given uniforms group to this instance.

@param {UniformsGroup} source - The uniforms group to copy.
@return {UniformsGroup} A reference to this uniforms group.