Sky = function Sky() {
	
		var skyShader = _three2['default'].ShaderLib['sky'];
		var skyUniforms = _three2['default'].UniformsUtils.clone(skyShader.uniforms);
	
		var skyMat = new _three2['default'].ShaderMaterial({
			fragmentShader: skyShader.fragmentShader,
			vertexShader: skyShader.vertexShader,
			uniforms: skyUniforms,
			side: _three2['default'].BackSide
		});
	
		var skyGeo = new _three2['default'].SphereBufferGeometry(450000, 32, 15);
		var skyMesh = new _three2['default'].Mesh(skyGeo, skyMat);
	
		// Expose variables
		this.mesh = skyMesh;
		this.uniforms = skyUniforms;
	}
@author zz85 / https://github.com/zz85

Based on 'A Practical Analytic Model for Daylight'
aka The Preetham Model, the de facto standard analytic skydome model
http://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf

First implemented by Simon Wallner
http://www.simonwallner.at/projects/atmospheric-scattering

Improved by Martin Upitis
http://blenderartists.org/forum/showthread.php?245954-preethams-sky-impementation-HDR

Three.js integration by zz85 http://twitter.com/blurspline