text: //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  // WARNING: This file was auto-generated, any change will be overridden in next release. Please use configs/es6.conf.js then run "npm run convert". //
  //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  import { Mesh } from './Mesh.js'
  import { ShaderMaterial } from '../materials/ShaderMaterial.js'
  import { BoxBufferGeometry } from '../geometries/BoxGeometry.js'
  import { Vector3 } from '../math/Vector3.js'
  import { BackSide } from '../constants.js'
  import { UniformsUtils } from '../renderers/shaders/UniformsUtils.js'
  
  var Sky = function () {
  
  	var shader = Sky.SkyShader;
  
  	var material = new ShaderMaterial( {
  		fragmentShader: shader.fragmentShader,
  		vertexShader: shader.vertexShader,
  		uniforms: UniformsUtils.clone( shader.uniforms ),
  		side: BackSide
  	} );
  
  	Mesh.call( this, new BoxBufferGeometry( 1, 1, 1 ), material );
  
  };
  
  Sky.prototype = Object.create( Mesh.prototype );
  
  Sky.SkyShader = {
  
  	uniforms: {
  		luminance: { value: 1 },
  		turbidity: { value: 2 },
  		rayleigh: { value: 1 },
  		mieCoefficient: { value: 0.005 },
  		mieDirectionalG: { value: 0.8 },
  		sunPosition: { value: new Vector3() }
  	},
  
  	vertexShader: [
  		'uniform vec3 sunPosition;',
  		'uniform float rayleigh;',
  		'uniform float turbidity;',
  		'uniform float mieCoefficient;',
  
  		'varying vec3 vWorldPosition;',
  		'varying vec3 vSunDirection;',
  		'varying float vSunfade;',
  		'varying vec3 vBetaR;',
  		'varying vec3 vBetaM;',
  		'varying float vSunE;',
  
  		'const vec3 up = vec3( 0.0, 1.0, 0.0 );',
  
  		// constants for atmospheric scattering
  		'const float e = 2.71828182845904523536028747135266249775724709369995957;',
  		'const float pi = 3.141592653589793238462643383279502884197169;',
  
  		// wavelength of used primaries, according to preetham
  		'const vec3 lambda = vec3( 680E-9, 550E-9, 450E-9 );',
  		// this pre-calcuation replaces older TotalRayleigh(vec3 lambda) function:
  		// (8.0 * pow(pi, 3.0) * pow(pow(n, 2.0) - 1.0, 2.0) * (6.0 + 3.0 * pn)) / (3.0 * N * pow(lambda, vec3(4.0)) * (6.0 - 7.0 * pn))
  		'const vec3 totalRayleigh = vec3( 5.804542996261093E-6, 1.3562911419845635E-5, 3.0265902468824876E-5 );',
  
  		// mie stuff
  		// K coefficient for the primaries
  		'const float v = 4.0;',
  		'const vec3 K = vec3( 0.686, 0.678, 0.666 );',
  		// MieConst = pi * pow( ( 2.0 * pi ) / lambda, vec3( v - 2.0 ) ) * K
  		'const vec3 MieConst = vec3( 1.8399918514433978E14, 2.7798023919660528E14, 4.0790479543861094E14 );',
  
  		// earth shadow hack
  		// cutoffAngle = pi / 1.95;
  		'const float cutoffAngle = 1.6110731556870734;',
  		'const float steepness = 1.5;',
  		'const float EE = 1000.0;',
  
  		'float sunIntensity( float zenithAngleCos ) {',
  		'	zenithAngleCos = clamp( zenithAngleCos, -1.0, 1.0 );',
  		'	return EE * max( 0.0, 1.0 - pow( e, -( ( cutoffAngle - acos( zenithAngleCos ) ) / steepness ) ) );',
  		'}',
  
  		'vec3 totalMie( float T ) {',
  		'	float c = ( 0.2 * T ) * 10E-18;',
  		'	return 0.434 * c * MieConst;',
  		'}',
  
  		'void main() {',
  
  		'	vec4 worldPosition = modelMatrix * vec4( position, 1.0 );',
  		'	vWorldPosition = worldPosition.xyz;',
  
  		'	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );',
  		'	gl_Position.z = gl_Position.w;', // set z to camera.far
  
  		'	vSunDirection = normalize( sunPosition );',
  
  		'	vSunE = sunIntensity( dot( vSunDirection, up ) );',
  
  		'	vSunfade = 1.0 - clamp( 1.0 - exp( ( sunPosition.y / 450000.0 ) ), 0.0, 1.0 );',
  
  		'	float rayleighCoefficient = rayleigh - ( 1.0 * ( 1.0 - vSunfade ) );',
  
  		// extinction (absorbtion + out scattering)
  		// rayleigh coefficients
  		'	vBetaR = totalRayleigh * rayleighCoefficient;',
  
  		// mie coefficients
  		'	vBetaM = totalMie( turbidity ) * mieCoefficient;',
  
  		'}'
  	].join( '\n' ),
  
  	fragmentShader: [
  		'varying vec3 vWorldPosition;',
  		'varying vec3 vSunDirection;',
  		'varying float vSunfade;',
  		'varying vec3 vBetaR;',
  		'varying vec3 vBetaM;',
  		'varying float vSunE;',
  
  		'uniform float luminance;',
  		'uniform float mieDirectionalG;',
  
  		'const vec3 cameraPos = vec3( 0.0, 0.0, 0.0 );',
  
  		// constants for atmospheric scattering
  		'const float pi = 3.141592653589793238462643383279502884197169;',
  
  		'const float n = 1.0003;', // refractive index of air
  		'const float N = 2.545E25;', // number of molecules per unit volume for air at
  									// 288.15K and 1013mb (sea level -45 celsius)
  
  		// optical length at zenith for molecules
  		'const float rayleighZenithLength = 8.4E3;',
  		'const float mieZenithLength = 1.25E3;',
  		'const vec3 up = vec3( 0.0, 1.0, 0.0 );',
  		// 66 arc seconds -> degrees, and the cosine of that
  		'const float sunAngularDiameterCos = 0.999956676946448443553574619906976478926848692873900859324;',
  
  		// 3.0 / ( 16.0 * pi )
  		'const float THREE_OVER_SIXTEENPI = 0.05968310365946075;',
  		// 1.0 / ( 4.0 * pi )
  		'const float ONE_OVER_FOURPI = 0.07957747154594767;',
  
  		'float rayleighPhase( float cosTheta ) {',
  		'	return THREE_OVER_SIXTEENPI * ( 1.0 + pow( cosTheta, 2.0 ) );',
  		'}',
  
  		'float hgPhase( float cosTheta, float g ) {',
  		'	float g2 = pow( g, 2.0 );',
  		'	float inverse = 1.0 / pow( 1.0 - 2.0 * g * cosTheta + g2, 1.5 );',
  		'	return ONE_OVER_FOURPI * ( ( 1.0 - g2 ) * inverse );',
  		'}',
  
  		// Filmic ToneMapping http://filmicgames.com/archives/75
  		'const float A = 0.15;',
  		'const float B = 0.50;',
  		'const float C = 0.10;',
  		'const float D = 0.20;',
  		'const float E = 0.02;',
  		'const float F = 0.30;',
  
  		'const float whiteScale = 1.0748724675633854;', // 1.0 / Uncharted2Tonemap(1000.0)
  
  		'vec3 Uncharted2Tonemap( vec3 x ) {',
  		'	return ( ( x * ( A * x + C * B ) + D * E ) / ( x * ( A * x + B ) + D * F ) ) - E / F;',
  		'}',
  
  		'void main() {',
  		// optical length
  		// cutoff angle at 90 to avoid singularity in next formula.
  		'	float zenithAngle = acos( max( 0.0, dot( up, normalize( vWorldPosition - cameraPos ) ) ) );',
  		'	float inverse = 1.0 / ( cos( zenithAngle ) + 0.15 * pow( 93.885 - ( ( zenithAngle * 180.0 ) / pi ), -1.253 ) );',
  		'	float sR = rayleighZenithLength * inverse;',
  		'	float sM = mieZenithLength * inverse;',
  
  		// combined extinction factor
  		'	vec3 Fex = exp( -( vBetaR * sR + vBetaM * sM ) );',
  
  		// in scattering
  		'	float cosTheta = dot( normalize( vWorldPosition - cameraPos ), vSunDirection );',
  
  		'	float rPhase = rayleighPhase( cosTheta * 0.5 + 0.5 );',
  		'	vec3 betaRTheta = vBetaR * rPhase;',
  
  		'	float mPhase = hgPhase( cosTheta, mieDirectionalG );',
  		'	vec3 betaMTheta = vBetaM * mPhase;',
  
  		'	vec3 Lin = pow( vSunE * ( ( betaRTheta + betaMTheta ) / ( vBetaR + vBetaM ) ) * ( 1.0 - Fex ), vec3( 1.5 ) );',
  		'	Lin *= mix( vec3( 1.0 ), pow( vSunE * ( ( betaRTheta + betaMTheta ) / ( vBetaR + vBetaM ) ) * Fex, vec3( 1.0 / 2.0 ) ), clamp( pow( 1.0 - dot( up, vSunDirection ), 5.0 ), 0.0, 1.0 ) );',
  
  		// nightsky
  		'	vec3 direction = normalize( vWorldPosition - cameraPos );',
  		'	float theta = acos( direction.y ); // elevation --> y-axis, [-pi/2, pi/2]',
  		'	float phi = atan( direction.z, direction.x ); // azimuth --> x-axis [-pi/2, pi/2]',
  		'	vec2 uv = vec2( phi, theta ) / vec2( 2.0 * pi, pi ) + vec2( 0.5, 0.0 );',
  		'	vec3 L0 = vec3( 0.1 ) * Fex;',
  
  		// composition + solar disc
  		'	float sundisk = smoothstep( sunAngularDiameterCos, sunAngularDiameterCos + 0.00002, cosTheta );',
  		'	L0 += ( vSunE * 19000.0 * Fex ) * sundisk;',
  
  		'	vec3 texColor = ( Lin + L0 ) * 0.04 + vec3( 0.0, 0.0003, 0.00075 );',
  
  		'	vec3 curr = Uncharted2Tonemap( ( log2( 2.0 / pow( luminance, 4.0 ) ) ) * texColor );',
  		'	vec3 color = curr * whiteScale;',
  
  		'	vec3 retColor = pow( color, vec3( 1.0 / ( 1.2 + ( 1.2 * vSunfade ) ) ) );',
  
  		'	gl_FragColor = vec4( retColor, 1.0 );',
  
  		'}'
  	].join( '\n' )
  
  };
  
  export { Sky }
  