Accueil / npm / three@0.186.1 / examples / jsm / objects / SkyMesh.js
SkyMesh.js
import {
BackSide,
BoxGeometry,
Mesh,
Vector3,
NodeMaterial
} from 'three/webgpu';
import { Fn, float, floor, fract, vec2, vec3, acos, add, mul, clamp, cos, dot, exp, max, min, mix, modelViewProjection, normalize, positionWorld, pow, smoothstep, sub, varyingProperty, vec4, uniform, cameraPosition, time, If, Loop } from 'three/tsl';
/**
* Represents a skydome for scene backgrounds. Based on [A Practical Analytic Model for Daylight](https://www.researchgate.net/publication/220720443_A_Practical_Analytic_Model_for_Daylight)
* aka The Preetham Model, the de facto standard for analytical skydomes.
*
* Note that this class can only be used with {@link WebGPURenderer}.
* When using {@link WebGLRenderer}, use {@link Sky}.
*
* More references:
*
* - {@link http://simonwallner.at/project/atmospheric-scattering/}
* - {@link http://blenderartists.org/forum/showthread.php?245954-preethams-sky-impementation-HDR}
*
* ```js
* const sky = new SkyMesh();
* sky.scale.setScalar( 10000 );
* scene.add( sky );
* ```
*
* It can be useful to hide the sun disc when generating an environment map to avoid artifacts
*
* ```js
* // disable before rendering environment map
* sky.showSunDisc.value = false;
* // ...
* // re-enable before scene sky box rendering
* sky.showSunDisc.value = true;
* ```
*
* @augments Mesh
* @three_import import { SkyMesh } from 'three/addons/objects/SkyMesh.js';
*/
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 cloud scale uniform.
*
* @type {UniformNode<float>}
*/
this.cloudScale = uniform( 0.0002 );
/**
* The cloud speed uniform.
*
* @type {UniformNode<float>}
*/
this.cloudSpeed = uniform( 0.00002 );
/**
* The cloud coverage uniform.
*
* @type {UniformNode<float>}
*/
this.cloudCoverage = uniform( 0.4 );
/**
* The cloud density uniform.
*
* @type {UniformNode<float>}
*/
this.cloudDensity = uniform( 0.4 );
/**
* The cloud elevation uniform.
*
* @type {UniformNode<float>}
*/
this.cloudElevation = uniform( 0.5 );
/**
* Whether to render the solar disc.
*
* @type {UniformNode<float>}
*/
this.showSunDisc = uniform( 1 );
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
* @deprecated Use isSkyMesh instead.
*/
this.isSky = true; // @deprecated, r182
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
*/
this.isSkyMesh = true;
// Varyings
const vSunDirection = varyingProperty( 'vec3' );
const vSunE = varyingProperty( 'float' );
const vBetaR = varyingProperty( 'vec3' );
const vBetaM = varyingProperty( 'vec3' );
const vertexNode = /*@__PURE__*/ Fn( () => {
// constants for atmospheric scattering
const e = float( 2.718281828459045 );
// const pi = float( 3.141592653589793 );
// 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 = sunDirection.y;
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 );
// sun fade
const sunfade = float( 1.0 ).sub( clamp( float( 1.0 ).sub( exp( this.sunPosition.y.div( 450000.0 ) ) ), 0, 1 ) );
// 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( 3.141592653589793 );
// 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( 0.9999566769464484 );
// 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, direction.y ) );
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, vSunDirection.y ), 5.0 ), 0.0, 1.0 ) ) );
// nightsky
const L0 = vec3( 0.1 ).mul( Fex );
// composition + solar disc
const sundisc = clamp( cosTheta.sub( sunAngularDiameterCos ).mul( 50000.0 ), 0.0, 1.0 ).mul( this.showSunDisc );
const sundiscColor = min( vSunE.mul( Fex ), 80.0 ).mul( 760.0 ).mul( sundisc );
const texColor = add( Lin, L0 ).mul( 0.04 ).add( sundiscColor ).add( vec3( 0.0, 0.0003, 0.00075 ) ).toVar();
// gradient at a lattice corner; sinless hash so every GPU produces the same clouds
const gradient = Fn( ( [ i ] ) => {
const p = fract( i.xyx.mul( vec3( 0.1031, 0.1030, 0.0973 ) ) ).toVar();
p.addAssign( dot( p, p.yzx.add( 33.33 ) ) );
return fract( p.xx.add( p.yz ).mul( p.zy ) ).mul( 2.0 ).sub( 1.0 );
} );
// 2D gradient noise: isotropic lobes like Perlin at value-noise cost
const noise = Fn( ( [ p ] ) => {
const i = floor( p );
const f = fract( p );
const u = f.mul( f ).mul( f ).mul( f.mul( f.mul( 6.0 ).sub( 15.0 ) ).add( 10.0 ) ); // quintic fade
const a = dot( gradient( i ), f );
const b = dot( gradient( i.add( vec2( 1.0, 0.0 ) ) ), f.sub( vec2( 1.0, 0.0 ) ) );
const c = dot( gradient( i.add( vec2( 0.0, 1.0 ) ) ), f.sub( vec2( 0.0, 1.0 ) ) );
const d = dot( gradient( i.add( vec2( 1.0, 1.0 ) ) ), f.sub( vec2( 1.0, 1.0 ) ) );
return mix( mix( a, b, u.x ), mix( c, d, u.x ), u.y ).mul( 1.6 ); // ~[-1,1]
} );
// fbm; per-octave drift makes clouds billow instead of scrolling as a rigid stamp
const fbm = Fn( ( [ position, drift ] ) => {
const p = vec2( position ).toVar();
const result = float( 0.0 ).toVar();
const amplitude = float( 1.0 ).toVar();
Loop( 4, () => {
result.addAssign( amplitude.mul( noise( p ) ) );
amplitude.mulAssign( 0.5 );
p.mulAssign( 2.0 ).addAssign( drift );
} );
return result;
} );
// Clouds
If( direction.y.greaterThan( 0.0 ).and( this.cloudCoverage.greaterThan( 0.0 ) ), () => {
// Project to cloud plane (higher elevation = clouds appear lower/closer)
const elevation = mix( 1.0, 0.1, this.cloudElevation );
const cloudUV = direction.xz.div( direction.y.mul( elevation ) ).toVar();
cloudUV.mulAssign( this.cloudScale );
cloudUV.addAssign( time.mul( this.cloudSpeed ) );
// Cloud density field
const evolve = time.mul( this.cloudSpeed ).mul( 300.0 );
const cloudNoise = fbm( cloudUV.mul( 1000.0 ), evolve ).mul( 0.7 ).add( 0.5 ).clamp( 0.0, 1.0 ).toVar();
// Large-scale coverage variation: clear gaps next to dense banks
const region = noise( cloudUV.mul( 300.0 ) ).mul( 0.37 ).add( 0.5 );
const cov = clamp( this.cloudCoverage.add( region.sub( 0.5 ).mul( 0.6 ) ), 0.0, 1.0 );
// Carve clouds where noise rises above the coverage level
const threshold = sub( 1.0, cov ).toVar();
const cloudMask = smoothstep( threshold, threshold.add( 0.3 ), cloudNoise ).toVar();
// Fade clouds near horizon (adjusted by elevation)
const horizonFade = smoothstep( 0.0, add( 0.03, mul( 0.06, this.cloudElevation ) ), direction.y );
cloudMask.mulAssign( horizonFade );
// Cloud lighting from the sky's own radiance
const dayFactor = smoothstep( - 0.08, 0.3, vSunDirection.y );
const sunColor = vSunE.mul( Fex ).mul( 0.22 ).mul( 0.04 ).toVar(); // 0.22 ~ albedo/pi, 0.04 = exposure; the aerial composite adds the eye-leg extinction
const skyAmbient = Lin.mul( 0.04 ).add( vec3( 0.0, 0.0003, 0.00075 ) );
// Beer-powder self-shadow from the sampled density
const depth = max( 0.0, cloudNoise.sub( threshold ) ).toVar();
const beer = exp( depth.mul( - 4.0 ) ).toVar();
const powder = sub( 1.0, beer.mul( beer ) ); // beer*beer == exp(-8*depth)
const shade = mix( 0.45, 1.0, beer.mul( powder ).mul( 2.6 ).clamp( 0.0, 1.0 ) ); // 2.6 = 1/0.385, normalizes beer*powder peak to 1
// Henyey-Greenstein forward lobe ( g = 0.7 ): silver lining on rims toward the sun
const silver = float( 0.51 ).div( pow( sub( 1.49, cosTheta.mul( 1.4 ) ), 1.5 ) ).clamp( 0.0, 3.0 ); // 0.51=1-g^2, 1.49=1+g^2, 1.4=2g
const edge = cloudMask.mul( sub( 1.0, cloudMask ) ).mul( 4.0 );
const cloudColor = skyAmbient.add( sunColor.mul( shade ) ).toVar();
cloudColor.addAssign( sunColor.mul( silver ).mul( edge ).mul( 0.6 ) );
cloudColor.mulAssign( dayFactor.max( 0.03 ) );
// Cloud opacity via Beer's law: density sets how solid the clouds get
const alpha = sub( 1.0, exp( depth.mul( this.cloudDensity ).mul( - 12.0 ) ) ).mul( horizonFade ).toVar();
// Occlude the sun disc/glow behind opaque cloud
texColor.subAssign( L0.mul( 0.04 ).add( sundiscColor ).mul( alpha ) );
// Composite through the atmosphere so distant clouds dissolve into haze
const cloudAerial = mix( texColor, cloudColor, Fex );
texColor.assign( mix( texColor, cloudAerial, alpha ) );
} );
return vec4( texColor, 1.0 );
} )();
material.side = BackSide;
material.depthWrite = false;
material.fog = false;
material.vertexNode = vertexNode;
material.colorNode = colorNode;
}
}
export { SkyMesh };