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- uniform sampler2D skySampler;
-
- varying vec4 fragPos; //fragment coordinates
- varying vec3 wT, wB, wN; //tangent binormal normal
- //varying vec3 wPos, pos, viewPos, sunPos;
- varying vec3 wPos, pos, viewPos;
- uniform vec3 cameraPos;
- uniform float bias, lumamount, contrast;
- //varying float luminance;
-
- uniform float luminance;
-
- uniform float sunx;
- uniform float suny;
- uniform float sunz;
-
- vec3 sunPos = vec3(sunx, suny, sunz);
- //vec3 sunPos = (sunx,suny,sunz);
-
- vec3 sunDirection = normalize(sunPos);
-
- uniform float turbidity, reileigh;
- float reileighCoefficient = reileigh;
-
- const float mieCoefficient = 0.005;
- const float mieDirectionalG = 0.80;
-
- vec3 tangentSpace(vec3 v)
- {
- vec3 vec;
- vec.xy=v.xy;
- vec.z=sqrt(1.0-dot(vec.xy,vec.xy));;
- vec.xyz= normalize(vec.x*wT+vec.y*wB+vec.z*wN);
- return vec;
- }
-
- // constants for atmospheric scattering
- const float e = 2.71828182845904523536028747135266249775724709369995957;
- 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)
- const float pn = 0.035; // depolatization factor for standard air
-
- // wavelength of used primaries, according to preetham
- const vec3 lambda = vec3(680E-9, 550E-9, 450E-9);
-
- // mie stuff
- // K coefficient for the primaries
- const vec3 K = vec3(0.686, 0.678, 0.666);
- const float v = 4.0;
-
- // optical length at zenith for molecules
- const float rayleighZenithLength = 8.4E3;
- const float mieZenithLength = 1.25E3;
- const vec3 up = vec3(0.0, 0.0, 1.0);
-
- const float EE = 120.0;
- const float sunAngularDiameterCos = 0.999956676946448443553574619906976478926848692873900859324;
-
- // earth shadow hack
- const float cutoffAngle = pi/1.95;
- const float steepness = 1.0; //1.5
-
-
- vec3 totalRayleigh(vec3 lambda)
- {
- 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));
- }
-
- float rayleighPhase(float cosTheta)
- {
- return (3.0 / (16.0*pi)) * (1.0 + pow(cosTheta, 2.0));
- // return (1.0 / (3.0*pi)) * (1.0 + pow(cosTheta, 2.0));
- // return (3.0 / 4.0) * (1.0 + pow(cosTheta, 2.0));
- }
-
- vec3 totalMie(vec3 lambda, vec3 K, float T)
- {
- float c = (0.2 * T ) * 10E-18;
- return 0.434 * c * pi * pow((2.0 * pi) / lambda, vec3(v - 2.0)) * K;
- }
-
- float hgPhase(float cosTheta, float g)
- {
- 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));
- }
-
- float sunIntensity(float zenithAngleCos)
- {
- return EE * max(0.0, 1.0 - exp(-((cutoffAngle - acos(zenithAngleCos))/steepness)));
- //return (EE * max(0.0, 1.0 - exp(-((cutoffAngle - acos(zenithAngleCos))/steepness))))*.001;
- //return 5;
- }
-
- float logLuminance(vec3 c)
- {
- return log(c.r * 0.2126 + c.g * 0.7152 + c.b * 0.0722);
- }
-
-
- float A = 0.15;
- float B = 0.50;
- float C = 0.10;
- float D = 0.20;
- float E = 0.02;
- float F = 0.30;
- float W = 1000.0;
-
- vec3 Uncharted2Tonemap(vec3 x)
- {
- return ((x*(A*x+C*B)+D*E)/(x*(A*x+B)+D*F))-E/F;
- }
-
-
- void main()
- {
- float sunfade = 1.0-clamp(1.0-exp(-(sunPos.z/500.0)),0.0,1.0);
-
- reileighCoefficient = reileighCoefficient - (1.0* (1.0-sunfade));
-
- float sunE = sunIntensity(dot(sunDirection, up));
-
- // extinction (absorbtion + out scattering)
- // rayleigh coefficients
- vec3 betaR = totalRayleigh(lambda) * reileighCoefficient;
-
- // mie coefficients
- vec3 betaM = totalMie(lambda, K, turbidity) * mieCoefficient;
-
- // optical length
- // cutoff angle at 90 to avoid singularity in next formula.
- float zenithAngle = acos(max(0.0, dot(up, normalize(wPos - cameraPos))));
- float sR = rayleighZenithLength / (cos(zenithAngle) + 0.15 * pow(93.885 - ((zenithAngle * 180.0) / pi), -1.253));
- float sM = mieZenithLength / (cos(zenithAngle) + 0.15 * pow(93.885 - ((zenithAngle * 180.0) / pi), -1.253));
-
-
-
- // combined extinction factor
- vec3 Fex = exp(-(betaR * sR + betaM * sM));
-
- // in scattering
- float cosTheta = dot(normalize(wPos - cameraPos), sunDirection);
-
- float rPhase = rayleighPhase(cosTheta*0.5+0.5);
- vec3 betaRTheta = betaR * rPhase;
-
- float mPhase = hgPhase(cosTheta, mieDirectionalG);
- vec3 betaMTheta = betaM * mPhase;
-
-
- vec3 Lin = pow(sunE * ((betaRTheta + betaMTheta) / (betaR + betaM)) * (1.0 - Fex),vec3(1.5));
- 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));
-
- //nightsky
- vec3 direction = normalize(wPos - 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 = texture2D(skySampler, uv).rgb+0.1 * Fex;
- vec3 L0 = vec3(0.1) * Fex;
-
- // composition + solar disc
- //if (cosTheta > sunAngularDiameterCos)
- float sundisk = smoothstep(sunAngularDiameterCos,sunAngularDiameterCos+0.00002,cosTheta);
- //if (normalize(wPos - cameraPos).z>0.0)
- L0 += (sunE * 19000.0 * Fex)*sundisk;
-
-
- vec3 whiteScale = 1.0/Uncharted2Tonemap(vec3(W));
-
- vec3 texColor = (Lin+L0);
- texColor *= 0.04 ;
- texColor += vec3(0.0,0.001,0.0025)*0.3;
-
- float g_fMaxLuminance = 1.0;
- float fLumScaled = 0.1 / luminance;
- float fLumCompressed = (fLumScaled * (1.0 + (fLumScaled / (g_fMaxLuminance * g_fMaxLuminance)))) / (1.0 + fLumScaled);
-
- float ExposureBias = fLumCompressed;
-
- 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*sunfade))));
-
-
- gl_FragColor.rgb = retColor;
-
- gl_FragColor.a = 1.0;
- }
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