class SkyMesh extends Mesh {
/**
* Constructs a new skydome.
*/
constructor() {
const material = new NodeMaterial();
super( new BoxGeometry( 1, 1, 1 ), material );
/**
* The turbidity uniform.
*
* @type {UniformNode<float>}
*/
this.turbidity = uniform( 2 );
/**
* The rayleigh uniform.
*
* @type {UniformNode<float>}
*/
this.rayleigh = uniform( 1 );
/**
* The mieCoefficient uniform.
*
* @type {UniformNode<float>}
*/
this.mieCoefficient = uniform( 0.005 );
/**
* The mieDirectionalG uniform.
*
* @type {UniformNode<float>}
*/
this.mieDirectionalG = uniform( 0.8 );
/**
* The sun position uniform.
*
* @type {UniformNode<vec3>}
*/
this.sunPosition = uniform( new Vector3() );
/**
* The up position.
*
* @type {UniformNode<vec3>}
*/
this.upUniform = uniform( new Vector3( 0, 1, 0 ) );
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
*/
this.isSky = true;
// Varyings
const vSunDirection = varyingProperty( 'vec3' );
const vSunE = varyingProperty( 'float' );
const vSunfade = varyingProperty( 'float' );
const vBetaR = varyingProperty( 'vec3' );
const vBetaM = varyingProperty( 'vec3' );
const vertexNode = /*@__PURE__*/ Fn( () => {
// constants for atmospheric scattering
const e = float( 2.71828182845904523536028747135266249775724709369995957 );
// const pi = float( 3.141592653589793238462643383279502884197169 );
// wavelength of used primaries, according to preetham
// const lambda = vec3( 680E-9, 550E-9, 450E-9 );
// this pre-calculation 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 totalRayleigh = vec3( 5.804542996261093E-6, 1.3562911419845635E-5, 3.0265902468824876E-5 );
// mie stuff
// K coefficient for the primaries
// const v = float( 4.0 );
// const K = vec3( 0.686, 0.678, 0.666 );
// MieConst = pi * pow( ( 2.0 * pi ) / lambda, vec3( v - 2.0 ) ) * K
const MieConst = vec3( 1.8399918514433978E14, 2.7798023919660528E14, 4.0790479543861094E14 );
// earth shadow hack
// cutoffAngle = pi / 1.95;
const cutoffAngle = float( 1.6110731556870734 );
const steepness = float( 1.5 );
const EE = float( 1000.0 );
// varying sun position
const sunDirection = normalize( this.sunPosition );
vSunDirection.assign( sunDirection );
// varying sun intensity
const angle = dot( sunDirection, this.upUniform );
const zenithAngleCos = clamp( angle, - 1, 1 );
const sunIntensity = EE.mul( max( 0.0, float( 1.0 ).sub( pow( e, cutoffAngle.sub( acos( zenithAngleCos ) ).div( steepness ).negate() ) ) ) );
vSunE.assign( sunIntensity );
// varying sun fade
const sunfade = float( 1.0 ).sub( clamp( float( 1.0 ).sub( exp( this.sunPosition.y.div( 450000.0 ) ) ), 0, 1 ) );
vSunfade.assign( sunfade );
// varying vBetaR
const rayleighCoefficient = this.rayleigh.sub( float( 1.0 ).mul( float( 1.0 ).sub( sunfade ) ) );
// extinction (absorption + out scattering)
// rayleigh coefficients
vBetaR.assign( totalRayleigh.mul( rayleighCoefficient ) );
// varying vBetaM
const c = float( 0.2 ).mul( this.turbidity ).mul( 10E-18 );
const totalMie = float( 0.434 ).mul( c ).mul( MieConst );
vBetaM.assign( totalMie.mul( this.mieCoefficient ) );
// position
const position = modelViewProjection;
position.z.assign( position.w ); // set z to camera.far
return position;
} )();
const colorNode = /*@__PURE__*/ Fn( () => {
// constants for atmospheric scattering
const pi = float( 3.141592653589793238462643383279502884197169 );
// optical length at zenith for molecules
const rayleighZenithLength = float( 8.4E3 );
const mieZenithLength = float( 1.25E3 );
// 66 arc seconds -> degrees, and the cosine of that
const sunAngularDiameterCos = float( 0.999956676946448443553574619906976478926848692873900859324 );
// 3.0 / ( 16.0 * pi )
const THREE_OVER_SIXTEENPI = float( 0.05968310365946075 );
// 1.0 / ( 4.0 * pi )
const ONE_OVER_FOURPI = float( 0.07957747154594767 );
//
const direction = normalize( positionWorld.sub( cameraPosition ) );
// optical length
// cutoff angle at 90 to avoid singularity in next formula.
const zenithAngle = acos( max( 0.0, dot( this.upUniform, direction ) ) );
const inverse = float( 1.0 ).div( cos( zenithAngle ).add( float( 0.15 ).mul( pow( float( 93.885 ).sub( zenithAngle.mul( 180.0 ).div( pi ) ), - 1.253 ) ) ) );
const sR = rayleighZenithLength.mul( inverse );
const sM = mieZenithLength.mul( inverse );
// combined extinction factor
const Fex = exp( mul( vBetaR, sR ).add( mul( vBetaM, sM ) ).negate() );
// in scattering
const cosTheta = dot( direction, vSunDirection );
// betaRTheta
const c = cosTheta.mul( 0.5 ).add( 0.5 );
const rPhase = THREE_OVER_SIXTEENPI.mul( float( 1.0 ).add( pow( c, 2.0 ) ) );
const betaRTheta = vBetaR.mul( rPhase );
// betaMTheta
const g2 = pow( this.mieDirectionalG, 2.0 );
const inv = float( 1.0 ).div( pow( float( 1.0 ).sub( float( 2.0 ).mul( this.mieDirectionalG ).mul( cosTheta ) ).add( g2 ), 1.5 ) );
const mPhase = ONE_OVER_FOURPI.mul( float( 1.0 ).sub( g2 ) ).mul( inv );
const betaMTheta = vBetaM.mul( mPhase );
const Lin = pow( vSunE.mul( add( betaRTheta, betaMTheta ).div( add( vBetaR, vBetaM ) ) ).mul( sub( 1.0, Fex ) ), vec3( 1.5 ) );
Lin.mulAssign( mix( vec3( 1.0 ), pow( vSunE.mul( add( betaRTheta, betaMTheta ).div( add( vBetaR, vBetaM ) ) ).mul( Fex ), vec3( 1.0 / 2.0 ) ), clamp( pow( sub( 1.0, dot( this.upUniform, vSunDirection ) ), 5.0 ), 0.0, 1.0 ) ) );
// nightsky
const L0 = vec3( 0.1 ).mul( Fex );
// composition + solar disc
const sundisk = smoothstep( sunAngularDiameterCos, sunAngularDiameterCos.add( 0.00002 ), cosTheta );
L0.addAssign( vSunE.mul( 19000.0 ).mul( Fex ).mul( sundisk ) );
const texColor = add( Lin, L0 ).mul( 0.04 ).add( vec3( 0.0, 0.0003, 0.00075 ) );
const retColor = pow( texColor, vec3( float( 1.0 ).div( float( 1.2 ).add( vSunfade.mul( 1.2 ) ) ) ) );
return vec4( retColor, 1.0 );
} )();
material.side = BackSide;
material.depthWrite = false;
material.vertexNode = vertexNode;
material.colorNode = colorNode;
}
}