mirror of
https://github.com/Doodle3D/Doodle3D-Slicer.git
synced 2024-11-26 15:34:57 +01:00
263 lines
8.2 KiB
JavaScript
Executable File
263 lines
8.2 KiB
JavaScript
Executable File
/**
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* @author zz85 / https://github.com/zz85
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*
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* Based on "A Practical Analytic Model for Daylight"
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* aka The Preetham Model, the de facto standard analytic skydome model
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* http://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf
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*
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* First implemented by Simon Wallner
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* http://www.simonwallner.at/projects/atmospheric-scattering
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*
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* Improved by Martin Upitis
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* http://blenderartists.org/forum/showthread.php?245954-preethams-sky-impementation-HDR
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*
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* Three.js integration by zz85 http://twitter.com/blurspline
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*/
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THREE.ShaderLib['sky'] = {
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uniforms: {
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luminance: { type: "f", value:1 },
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turbidity: { type: "f", value:2 },
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reileigh: { type: "f", value:1 },
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mieCoefficient: { type: "f", value:0.005 },
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mieDirectionalG: { type: "f", value:0.8 },
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sunPosition: { type: "v3", value: new THREE.Vector3() }
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},
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vertexShader: [
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"varying vec3 vWorldPosition;",
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"void main() {",
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"vec4 worldPosition = modelMatrix * vec4( position, 1.0 );",
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"vWorldPosition = worldPosition.xyz;",
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"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
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"}",
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].join("\n"),
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fragmentShader: [
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"uniform sampler2D skySampler;",
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"uniform vec3 sunPosition;",
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"varying vec3 vWorldPosition;",
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"vec3 cameraPos = vec3(0., 0., 0.);",
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"// uniform sampler2D sDiffuse;",
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"// const float turbidity = 10.0; //",
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"// const float reileigh = 2.; //",
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"// const float luminance = 1.0; //",
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"// const float mieCoefficient = 0.005;",
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"// const float mieDirectionalG = 0.8;",
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"uniform float luminance;",
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"uniform float turbidity;",
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"uniform float reileigh;",
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"uniform float mieCoefficient;",
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"uniform float mieDirectionalG;",
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"vec3 sunDirection = normalize(sunPosition);",
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"float reileighCoefficient = reileigh;",
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"// constants for atmospheric scattering",
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"const float e = 2.71828182845904523536028747135266249775724709369995957;",
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"const float pi = 3.141592653589793238462643383279502884197169;",
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"const float n = 1.0003; // refractive index of air",
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"const float N = 2.545E25; // number of molecules per unit volume for air at",
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"// 288.15K and 1013mb (sea level -45 celsius)",
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"const float pn = 0.035; // depolatization factor for standard air",
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"// wavelength of used primaries, according to preetham",
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"const vec3 lambda = vec3(680E-9, 550E-9, 450E-9);",
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"// mie stuff",
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"// K coefficient for the primaries",
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"const vec3 K = vec3(0.686, 0.678, 0.666);",
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"const float v = 4.0;",
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"// optical length at zenith for molecules",
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"const float rayleighZenithLength = 8.4E3;",
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"const float mieZenithLength = 1.25E3;",
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"const vec3 up = vec3(0.0, 1.0, 0.0);",
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"const float EE = 1000.0;",
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"const float sunAngularDiameterCos = 0.999956676946448443553574619906976478926848692873900859324;",
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"// 66 arc seconds -> degrees, and the cosine of that",
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"// earth shadow hack",
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"const float cutoffAngle = pi/1.95;",
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"const float steepness = 1.5;",
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"vec3 totalRayleigh(vec3 lambda)",
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"{",
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"return (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));",
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"}",
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// see http://blenderartists.org/forum/showthread.php?321110-Shaders-and-Skybox-madness
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"// A simplied version of the total Reayleigh scattering to works on browsers that use ANGLE",
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"vec3 simplifiedRayleigh()",
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"{",
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"return 0.0005 / vec3(94, 40, 18);",
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// return 0.00054532832366 / (3.0 * 2.545E25 * pow(vec3(680E-9, 550E-9, 450E-9), vec3(4.0)) * 6.245);
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"}",
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"float rayleighPhase(float cosTheta)",
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"{ ",
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"return (3.0 / (16.0*pi)) * (1.0 + pow(cosTheta, 2.0));",
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"// return (1.0 / (3.0*pi)) * (1.0 + pow(cosTheta, 2.0));",
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"// return (3.0 / 4.0) * (1.0 + pow(cosTheta, 2.0));",
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"}",
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"vec3 totalMie(vec3 lambda, vec3 K, float T)",
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"{",
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"float c = (0.2 * T ) * 10E-18;",
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"return 0.434 * c * pi * pow((2.0 * pi) / lambda, vec3(v - 2.0)) * K;",
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"}",
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"float hgPhase(float cosTheta, float g)",
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"{",
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"return (1.0 / (4.0*pi)) * ((1.0 - pow(g, 2.0)) / pow(1.0 - 2.0*g*cosTheta + pow(g, 2.0), 1.5));",
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"}",
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"float sunIntensity(float zenithAngleCos)",
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"{",
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"return EE * max(0.0, 1.0 - exp(-((cutoffAngle - acos(zenithAngleCos))/steepness)));",
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"}",
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"// float logLuminance(vec3 c)",
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"// {",
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"// return log(c.r * 0.2126 + c.g * 0.7152 + c.b * 0.0722);",
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"// }",
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"// Filmic ToneMapping http://filmicgames.com/archives/75",
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"float A = 0.15;",
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"float B = 0.50;",
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"float C = 0.10;",
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"float D = 0.20;",
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"float E = 0.02;",
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"float F = 0.30;",
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"float W = 1000.0;",
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"vec3 Uncharted2Tonemap(vec3 x)",
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"{",
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"return ((x*(A*x+C*B)+D*E)/(x*(A*x+B)+D*F))-E/F;",
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"}",
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"void main() ",
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"{",
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"float sunfade = 1.0-clamp(1.0-exp((sunPosition.y/450000.0)),0.0,1.0);",
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"// luminance = 1.0 ;// vWorldPosition.y / 450000. + 0.5; //sunPosition.y / 450000. * 1. + 0.5;",
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"// gl_FragColor = vec4(sunfade, sunfade, sunfade, 1.0);",
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"reileighCoefficient = reileighCoefficient - (1.0* (1.0-sunfade));",
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"float sunE = sunIntensity(dot(sunDirection, up));",
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"// extinction (absorbtion + out scattering) ",
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"// rayleigh coefficients",
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// "vec3 betaR = totalRayleigh(lambda) * reileighCoefficient;",
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"vec3 betaR = simplifiedRayleigh() * reileighCoefficient;",
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"// mie coefficients",
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"vec3 betaM = totalMie(lambda, K, turbidity) * mieCoefficient;",
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"// optical length",
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"// cutoff angle at 90 to avoid singularity in next formula.",
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"float zenithAngle = acos(max(0.0, dot(up, normalize(vWorldPosition - cameraPos))));",
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"float sR = rayleighZenithLength / (cos(zenithAngle) + 0.15 * pow(93.885 - ((zenithAngle * 180.0) / pi), -1.253));",
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"float sM = mieZenithLength / (cos(zenithAngle) + 0.15 * pow(93.885 - ((zenithAngle * 180.0) / pi), -1.253));",
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"// combined extinction factor ",
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"vec3 Fex = exp(-(betaR * sR + betaM * sM));",
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"// in scattering",
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"float cosTheta = dot(normalize(vWorldPosition - cameraPos), sunDirection);",
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"float rPhase = rayleighPhase(cosTheta*0.5+0.5);",
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"vec3 betaRTheta = betaR * rPhase;",
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"float mPhase = hgPhase(cosTheta, mieDirectionalG);",
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"vec3 betaMTheta = betaM * mPhase;",
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"vec3 Lin = pow(sunE * ((betaRTheta + betaMTheta) / (betaR + betaM)) * (1.0 - Fex),vec3(1.5));",
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"Lin *= mix(vec3(1.0),pow(sunE * ((betaRTheta + betaMTheta) / (betaR + betaM)) * Fex,vec3(1.0/2.0)),clamp(pow(1.0-dot(up, sunDirection),5.0),0.0,1.0));",
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"//nightsky",
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"vec3 direction = normalize(vWorldPosition - cameraPos);",
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"float theta = acos(direction.y); // elevation --> y-axis, [-pi/2, pi/2]",
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"float phi = atan(direction.z, direction.x); // azimuth --> x-axis [-pi/2, pi/2]",
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"vec2 uv = vec2(phi, theta) / vec2(2.0*pi, pi) + vec2(0.5, 0.0);",
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"// vec3 L0 = texture2D(skySampler, uv).rgb+0.1 * Fex;",
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"vec3 L0 = vec3(0.1) * Fex;",
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"// composition + solar disc",
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"//if (cosTheta > sunAngularDiameterCos)",
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"float sundisk = smoothstep(sunAngularDiameterCos,sunAngularDiameterCos+0.00002,cosTheta);",
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"// if (normalize(vWorldPosition - cameraPos).y>0.0)",
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"L0 += (sunE * 19000.0 * Fex)*sundisk;",
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"vec3 whiteScale = 1.0/Uncharted2Tonemap(vec3(W));",
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"vec3 texColor = (Lin+L0); ",
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"texColor *= 0.04 ;",
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"texColor += vec3(0.0,0.001,0.0025)*0.3;",
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"float g_fMaxLuminance = 1.0;",
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"float fLumScaled = 0.1 / luminance; ",
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"float fLumCompressed = (fLumScaled * (1.0 + (fLumScaled / (g_fMaxLuminance * g_fMaxLuminance)))) / (1.0 + fLumScaled); ",
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"float ExposureBias = fLumCompressed;",
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"vec3 curr = Uncharted2Tonemap((log2(2.0/pow(luminance,4.0)))*texColor);",
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"vec3 color = curr*whiteScale;",
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"vec3 retColor = pow(color,vec3(1.0/(1.2+(1.2*sunfade))));",
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"gl_FragColor.rgb = retColor;",
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"gl_FragColor.a = 1.0;",
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"}",
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].join("\n")
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};
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THREE.Sky = function () {
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var skyShader = THREE.ShaderLib[ "sky" ];
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var skyUniforms = THREE.UniformsUtils.clone( skyShader.uniforms );
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var skyMat = new THREE.ShaderMaterial( {
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fragmentShader: skyShader.fragmentShader,
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vertexShader: skyShader.vertexShader,
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uniforms: skyUniforms,
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side: THREE.BackSide
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} );
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var skyGeo = new THREE.SphereGeometry( 450000, 32, 15 );
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var skyMesh = new THREE.Mesh( skyGeo, skyMat );
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// Expose variables
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this.mesh = skyMesh;
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this.uniforms = skyUniforms;
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};
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