New file |
| | |
| | | import { |
| | | BackSide, |
| | | BoxGeometry, |
| | | Mesh, |
| | | ShaderMaterial, |
| | | UniformsUtils, |
| | | Vector3 |
| | | } from '../three.module.js'; |
| | | |
| | | /** |
| | | * Based on "A Practical Analytic Model for Daylight" |
| | | * aka The Preetham Model, the de facto standard analytic skydome model |
| | | * https://www.researchgate.net/publication/220720443_A_Practical_Analytic_Model_for_Daylight |
| | | * |
| | | * 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 |
| | | */ |
| | | |
| | | class Sky extends Mesh { |
| | | |
| | | constructor() { |
| | | |
| | | const shader = Sky.SkyShader; |
| | | |
| | | const material = new ShaderMaterial( { |
| | | name: 'SkyShader', |
| | | fragmentShader: shader.fragmentShader, |
| | | vertexShader: shader.vertexShader, |
| | | uniforms: UniformsUtils.clone( shader.uniforms ), |
| | | side: BackSide, |
| | | depthWrite: false |
| | | } ); |
| | | |
| | | super( new BoxGeometry( 1, 1, 1 ), material ); |
| | | |
| | | } |
| | | |
| | | } |
| | | |
| | | Sky.prototype.isSky = true; |
| | | |
| | | Sky.SkyShader = { |
| | | |
| | | uniforms: { |
| | | 'turbidity': { value: 2 }, |
| | | 'rayleigh': { value: 1 }, |
| | | 'mieCoefficient': { value: 0.005 }, |
| | | 'mieDirectionalG': { value: 0.8 }, |
| | | 'sunPosition': { value: new Vector3() }, |
| | | 'up': { value: new Vector3( 0, 1, 0 ) } |
| | | }, |
| | | |
| | | vertexShader: /* glsl */` |
| | | uniform vec3 sunPosition; |
| | | uniform float rayleigh; |
| | | uniform float turbidity; |
| | | uniform float mieCoefficient; |
| | | uniform vec3 up; |
| | | |
| | | varying vec3 vWorldPosition; |
| | | varying vec3 vSunDirection; |
| | | varying float vSunfade; |
| | | varying vec3 vBetaR; |
| | | varying vec3 vBetaM; |
| | | varying float vSunE; |
| | | |
| | | // 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; |
| | | |
| | | }`, |
| | | |
| | | fragmentShader: /* glsl */` |
| | | varying vec3 vWorldPosition; |
| | | varying vec3 vSunDirection; |
| | | varying float vSunfade; |
| | | varying vec3 vBetaR; |
| | | varying vec3 vBetaM; |
| | | varying float vSunE; |
| | | |
| | | uniform float mieDirectionalG; |
| | | uniform vec3 up; |
| | | |
| | | 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; |
| | | // 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 ); |
| | | } |
| | | |
| | | void main() { |
| | | |
| | | vec3 direction = normalize( vWorldPosition - cameraPos ); |
| | | |
| | | // optical length |
| | | // cutoff angle at 90 to avoid singularity in next formula. |
| | | float zenithAngle = acos( max( 0.0, dot( up, direction ) ) ); |
| | | 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( direction, 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 |
| | | 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 retColor = pow( texColor, vec3( 1.0 / ( 1.2 + ( 1.2 * vSunfade ) ) ) ); |
| | | |
| | | gl_FragColor = vec4( retColor, 1.0 ); |
| | | |
| | | #include <tonemapping_fragment> |
| | | #include <encodings_fragment> |
| | | |
| | | }` |
| | | |
| | | }; |
| | | |
| | | export { Sky }; |