function clamp( x ) {

			return Math.min( Math.max( x, -1 ), 1 );

		}
@author mrdoob / http://mrdoob.com/
@author kile / http://kile.stravaganza.org/
@author philogb / http://blog.thejit.org/
@author mikael emtinger / http://gomo.se/
@author egraether / http://egraether.com/
@author WestLangley / http://github.com/WestLangley