src/video/webgl/compositor.js
function (x, y, w, h) {
            this.gl.viewport(x, y, w, h);
        }
function (x, y, w, h) {
            this.gl.viewport(x, y, w, h);
        }
function ( x , y , w , h ) { this . gl . viewport ( x , y , w , h ) ; }
Sets the viewport
@name setViewport
@memberOf me.WebGLRenderer.Compositor
@function
@param {Number} x x position of viewport
@param {Number} y y position of viewport
@param {Number} width width of viewport
@param {Number} height height of viewport
Sets the viewport