public static SilverLiningSpectrum operator *(SilverLiningSpectrum s1, SilverLiningSpectrum s2)
{
SilverLiningSpectrum sOut = new SilverLiningSpectrum();
for (int i = 0; i < NSAMPLES; i++)
{
sOut.powers[i] = s1.powers[i] * s2.powers[i];
}
return(sOut);
}
private void ComputeSun (double altitude)
{
Vector3 sunPos = ephemeris.GetSunPositionHorizon ();
sunPos.Normalize ();
double cosZenith = sunPos.y;
if (lastSunT != T || lastSunZenith != cosZenith) {
lastSunT = T;
lastSunZenith = cosZenith;
lightingChanged = true;
double solarAltitude = DEGREES(Math.Asin(sunPos.y));
if (solarAltitude > 1.0)
{
perezBlend = 0;
} else if (solarAltitude < 0) {
perezBlend = 1.0f;
} else {
perezBlend = 1.0f - (float)solarAltitude;
}
if (cosZenith > 0) {
double zenithAngle = Math.Acos (cosZenith);
SilverLiningSpectrum solarDirect = new SilverLiningSpectrum ();
SilverLiningSpectrum solarScattered = new SilverLiningSpectrum ();
sunSpectrum.ApplyAtmosphericTransmittance (zenithAngle, cosZenith, T, altitude, ref solarDirect, ref solarScattered);
sunTransmittedLuminance = solarDirect.ToXYZ ();
sunScatteredLuminance = solarScattered.ToXYZ ();
// Apply sunset color tweaks
double alpha = zenithAngle / (PI * 0.5);
for (int i = 0; i < boostExp; i++)
alpha *= alpha;
sunScatteredLuminance.x *= (float)(1.0 + alpha * XBoost);
sunScatteredLuminance.y *= (float)(1.0 + alpha * YBoost);
sunScatteredLuminance.z *= (float)(1.0 + alpha * ZBoost);
} else {
// In twilight conditions, we lookup luminance based on experimental results
// on cloudless nights.
int lower = (int)Math.Floor (solarAltitude);
int higher = (int)Math.Ceiling (solarAltitude);
float alpha = (float)(solarAltitude - lower);
float a = 0;
float b = 0;
if (lower >= -16 && higher >= -16) {
a = twilightLuminance[lower];
b = twilightLuminance[higher];
}
// Blend light from sunset
const double epsilon = 0.001;
SilverLiningSpectrum solarDirect = new SilverLiningSpectrum ();
SilverLiningSpectrum solarScattered = new SilverLiningSpectrum ();
double zenithAngle = PI * 0.5 - epsilon;
sunSpectrum.ApplyAtmosphericTransmittance (zenithAngle, Math.Cos (zenithAngle), T, altitude, ref solarDirect, ref solarScattered);
sunTransmittedLuminance = solarDirect.ToXYZ ();
sunScatteredLuminance = solarScattered.ToXYZ ();
float Y = (1 - alpha) * a + alpha * b;
// luminance per lookup table
float x = 0.25f;
float y = 0.25f;
float minDirectional = 0.1f;
float X = x * (Y / y);
float Z = (1.0f - x - y) * (Y / y);
alpha = -(float)solarAltitude / 2.0f;
if (alpha > 1.0f)
alpha = 1.0f;
if (alpha < 0)
alpha = 0;
alpha = alpha * alpha;
sunTransmittedLuminance = sunTransmittedLuminance * Y * minDirectional * alpha + sunTransmittedLuminance * (1.0f - alpha);
Vector3 twilight = new Vector3 (X, Y, Z);
sunScatteredLuminance = twilight * alpha + sunScatteredLuminance * (1.0f - alpha);
// Apply sunset color tweaks
sunScatteredLuminance.x *= 1.0f + XBoost;
sunScatteredLuminance.y *= 1.0f + YBoost;
sunScatteredLuminance.z *= 1.0f + ZBoost;
}
if (isOvercast) {
sunTransmittedLuminance = (sunTransmittedLuminance * (overcastBlend * overcastTransmission)) + (sunTransmittedLuminance * (1.0f - overcastBlend));
sunScatteredLuminance = (sunScatteredLuminance * (overcastBlend * overcastTransmission)) + (sunScatteredLuminance * (1.0f - overcastBlend));
}
sunTransmittedLuminance = sunTransmittedLuminance * sunTransmissionScale;
sunScatteredLuminance = sunScatteredLuminance * sunScatteredScale;
}
}
public SilverLiningSky()
{
sunDistance *= (float)SilverLining.unitScale;
moonDistance *= (float)SilverLining.unitScale;
H *= (float)SilverLining.unitScale;
ephemeris = new SilverLiningEphemeris ();
InitTwilightLuminances ();
sunSpectrum = new SilverLiningSolarSpectrum ();
lunarSpectrum = new SilverLiningLunarSpectrum ();
XYZ2RGB = new SilverLiningMatrix3 (3.240479, -0.969256, 0.055648, -1.537150, 1.875992, -0.204043, -0.498535, 0.041556, 1.057311);
XYZ2RGB4 = new Matrix4x4 ();
XYZ2RGB4[0, 0] = 3.240479f;
XYZ2RGB4[0, 1] = -0.969256f;
XYZ2RGB4[0, 2] = 0.055648f;
XYZ2RGB4[0, 3] = 0.0f;
XYZ2RGB4[1, 0] = -1.537150f;
XYZ2RGB4[1, 1] = 1.875992f;
XYZ2RGB4[1, 2] = -0.204043f;
XYZ2RGB4[1, 3] = 0.0f;
XYZ2RGB4[2, 0] = -0.498535f;
XYZ2RGB4[2, 1] = 0.041556f;
XYZ2RGB4[2, 2] = 1.057311f;
XYZ2RGB4[2, 3] = 0.0f;
XYZ2RGB4[3, 0] = 0.0f;
XYZ2RGB4[3, 1] = 0.0f;
XYZ2RGB4[3, 2] = 0.0f;
XYZ2RGB4[3, 3] = 1.0f;
}
public void ApplyAtmosphericTransmittance(double zenithAngle, double cosZenith, double T, double alt,
ref SilverLiningSpectrum directIrradiance,
ref SilverLiningSpectrum scatteredIrradiance)
{
double beta = 0.04608 * T - 0.04586;
double zenithDeg = DEGREES(zenithAngle);
const double modelLimit = 90.0; //93.885
if (zenithDeg < modelLimit)
{
// SPECTRL2 air mass model
double m = 1.0 / (cosZenith + 0.50572 * Math.Pow(96.07995 - zenithDeg, -1.6364));
m *= airMassMultiplier;
// Account for high altitude. As you lose atmosphere, less scattering occurs.
H *= SilverLining.unitScale;
double isothermalEffect = Math.Exp(-(alt / H));
m *= isothermalEffect;
// ozone mass
double Mo = 1.003454 / Math.Sqrt(cosZenith * cosZenith + 0.006908);
const double omega = 0.945; // single scaterring albedo, 0.4 microns
const double omegap = 0.095; // Wavelength variation factor
const double assym = 0.65; // aerosol assymetry factor
double alg = Math.Log(1.0 - assym);
double afs = alg * (1.459 + alg * (0.1595 + alg * 0.4129));
double bfs = alg * (0.0783 + alg * (-0.3824 - alg * 0.5874));
double fsp = 1.0 - 0.5 * Math.Exp((afs + bfs / 1.8) / 1.8);
double fs = 1.0 - 0.5 * Math.Exp((afs + bfs * cosZenith) * cosZenith);
for (int i = 0; i < NSAMPLES; i++)
{
double um = 0.380 + (i * 0.005);
// Rayleigh scattering
double Tr = Math.Exp(-m / (Math.Pow(um, 4.0) * (115.6406 - (1.3366 / (um * um)))));
// Aerosols
double a;
if (um < 0.5)
{
a = 1.0274;
}
else
{
a = 1.2060;
}
double c1 = beta * Math.Pow(2.0 * um, -a);
double Ta = Math.Exp(-c1 * m);
// Water vapor
double aWM = Aw[i] * W * m;
double Tw = Math.Exp(-0.2385 * aWM / Math.Pow(1.0 + 20.07 * aWM, 0.45));
// Ozone
double To = Math.Exp(-Ao[i] * O3 * Mo);
// Mixed gas is only important in infrared
double Tm = Math.Exp((-1.41 * Au[i] * m) / Math.Pow(1.0 + 118.3 * Au[i] * m, 0.45));
// Aerosol scattering
double logUmOver4 = Math.Log(um / 0.4);
double omegl = omega * Math.Exp(-omegap * logUmOver4 * logUmOver4);
double Tas = Math.Exp(-omegl * c1 * m);
// Aerosol absorptance
double Taa = Math.Exp((omegl - 1.0) * c1 * m);
// Primed Rayleigh scattering (m = 1.8)
double Trp = Math.Exp(-1.8 / (um * um * um * um) * (115.6406 - 1.3366 / (um * um)));
// Primed water vapor scattering
double Twp = Math.Exp(-0.4293 * Aw[i] * W / Math.Pow((1.0 + 36.126 * Aw[i] * W), 0.45));
// Mixed gas
double Tup = Math.Exp(-2.538 * Au[i] / Math.Pow((1.0 + 212.94 * Au[i]), 0.45));
// Primed aerosol scattering
double Tasp = Math.Exp(-omegl * c1 * 1.8);
// Primed aerosol absorptance
double Taap = Math.Exp((omegl - 1.0) * c1 * 1.8);
// Direct energy
double xmit = Tr * Ta * Tw * To * Tm;
directIrradiance.powers[i] = powers[i] * xmit;
// diffuse energy
double c2 = powers[i] * To * Tw * Tm * cosZenith * Taa;
double c4 = 1.0;
if (um <= 0.45)
{
c4 = Math.Pow((um + 0.55), 1.8);
}
double rhoa = Twp * Tup * Taap * (0.5 * (1.0 - Trp) + (1.0 - fsp) * Trp * (1.0 - Tasp));
double dray = c2 * (1.0 - Math.Pow(Tr, 0.95)) / 2.0;
double daer = c2 * Math.Pow(Tr, 1.5) * (1.0 - Tas) * fs;
double drgd = (directIrradiance.powers[i] * cosZenith + dray + daer) * rho * rhoa / (1.0 - rho * rhoa);
scatteredIrradiance.powers[i] = (dray + daer + drgd) * c4;
if (scatteredIrradiance.powers[i] < 0)
{
scatteredIrradiance.powers[i] = 0;
}
}
}
else
{
for (int i = 0; i < NSAMPLES; i++)
{
directIrradiance.powers[i] = 0;
scatteredIrradiance.powers[i] = 0;
}
}
}
public void ApplyAtmosphericTransmittance(double zenithAngle, double cosZenith, double T, double alt,
ref SilverLiningSpectrum directIrradiance,
ref SilverLiningSpectrum scatteredIrradiance)
{
double beta = 0.04608 * T - 0.04586;
double zenithDeg = DEGREES(zenithAngle);
const double modelLimit = 90.0; //93.885
if (zenithDeg < modelLimit)
{
// SPECTRL2 air mass model
double m = 1.0 / (cosZenith + 0.50572 * Math.Pow(96.07995 - zenithDeg, -1.6364));
m *= airMassMultiplier;
// Account for high altitude. As you lose atmosphere, less scattering occurs.
H *= SilverLining.unitScale;
double isothermalEffect = Math.Exp(-(alt / H));
m *= isothermalEffect;
// ozone mass
double Mo = 1.003454 / Math.Sqrt ( cosZenith * cosZenith + 0.006908 );
const double omega = 0.945; // single scaterring albedo, 0.4 microns
const double omegap = 0.095; // Wavelength variation factor
const double assym = 0.65; // aerosol assymetry factor
double alg = Math.Log(1.0 - assym);
double afs = alg * (1.459 + alg * (0.1595 + alg * 0.4129));
double bfs = alg * (0.0783 + alg * (-0.3824 - alg * 0.5874));
double fsp = 1.0 - 0.5 * Math.Exp((afs + bfs / 1.8) / 1.8);
double fs = 1.0 - 0.5 * Math.Exp((afs + bfs * cosZenith) * cosZenith);
for (int i = 0; i < NSAMPLES; i++)
{
double um = 0.380 + (i * 0.005);
// Rayleigh scattering
double Tr = Math.Exp(-m / (Math.Pow(um, 4.0) * (115.6406 - (1.3366 / (um * um)))));
// Aerosols
double a;
if (um < 0.5) {
a = 1.0274;
} else {
a = 1.2060;
}
double c1 = beta * Math.Pow(2.0 * um, -a);
double Ta = Math.Exp(-c1 * m);
// Water vapor
double aWM = Aw[i] * W * m;
double Tw = Math.Exp(-0.2385 * aWM / Math.Pow(1.0 + 20.07 * aWM, 0.45));
// Ozone
double To = Math.Exp(-Ao[i] * O3 * Mo);
// Mixed gas is only important in infrared
double Tm = Math.Exp((-1.41 * Au[i] * m) / Math.Pow(1.0 + 118.3 * Au[i] * m, 0.45));
// Aerosol scattering
double logUmOver4 = Math.Log(um / 0.4);
double omegl = omega * Math.Exp (-omegap * logUmOver4 * logUmOver4);
double Tas = Math.Exp(-omegl * c1 * m);
// Aerosol absorptance
double Taa = Math.Exp((omegl - 1.0) * c1 * m);
// Primed Rayleigh scattering (m = 1.8)
double Trp = Math.Exp(-1.8 / (um * um * um * um) * (115.6406 - 1.3366 / (um * um)));
// Primed water vapor scattering
double Twp = Math.Exp(-0.4293 * Aw[i] * W / Math.Pow((1.0 + 36.126 * Aw[i] * W), 0.45));
// Mixed gas
double Tup = Math.Exp(-2.538 * Au[i] / Math.Pow((1.0 + 212.94 * Au[i]), 0.45));
// Primed aerosol scattering
double Tasp = Math.Exp(-omegl * c1 * 1.8);
// Primed aerosol absorptance
double Taap = Math.Exp((omegl - 1.0) * c1 * 1.8);
// Direct energy
double xmit = Tr * Ta * Tw * To * Tm;
directIrradiance.powers[i] = powers[i] * xmit;
// diffuse energy
double c2 = powers[i] * To * Tw * Tm * cosZenith * Taa;
double c4 = 1.0;
if (um <= 0.45) {
c4 = Math.Pow( (um + 0.55), 1.8);
}
double rhoa = Twp * Tup * Taap * (0.5 * (1.0 - Trp) + (1.0 - fsp) * Trp * (1.0 - Tasp) );
double dray = c2 * (1.0 - Math.Pow(Tr, 0.95)) / 2.0;
double daer = c2 * Math.Pow(Tr, 1.5) * (1.0 - Tas) * fs;
double drgd = ( directIrradiance.powers[i] * cosZenith + dray + daer) * rho * rhoa / (1.0 - rho * rhoa);
scatteredIrradiance.powers[i] = (dray + daer + drgd) * c4;
if (scatteredIrradiance.powers[i] < 0)
scatteredIrradiance.powers[i] = 0;
}
}
else
{
for (int i = 0; i < NSAMPLES; i++)
{
directIrradiance.powers[i] = 0;
scatteredIrradiance.powers[i] = 0;
}
}
}
public static SilverLiningSpectrum operator * (SilverLiningSpectrum s1, SilverLiningSpectrum s2)
{
SilverLiningSpectrum sOut = new SilverLiningSpectrum();
for (int i = 0; i < NSAMPLES; i++)
{
sOut.powers[i] = s1.powers[i] * s2.powers[i];
}
return sOut;
}
