public static MyDColor Integrate(double x0, double x1, Func <double, MyDColor> f, int num = 15)
{
double dx = (x1 - x0) / (num - 1);
MyDColor acc = new MyDColor();
MyDColor f0 = f(x0);
MyDColor f1 = f(x1);
acc.R = (f0.R + f1.R) / 2;
acc.G = (f0.G + f1.G) / 2;
acc.B = (f0.B + f1.B) / 2;
for (int i = 1; i < (num - 1); i++)
{
var fi = f(x0 + i * dx);
acc.R += fi.R;
acc.G += fi.G;
acc.B += fi.B;
}
acc.R *= dx;
acc.G *= dx;
acc.B *= dx;
return(acc);
}
public bool TryGetValues(double dist,
ref MyDColor attenuation,
ref MyDColor airColorR,
ref MyDColor airColorM,
ref MyDColor directPart)
{
double[] values = new double[12];
if (!inters.TryGetValue(dist, values))
{
return(false);
}
attenuation.R = values[0];
attenuation.G = values[1];
attenuation.B = values[2];
airColorR.R = values[3];
airColorR.G = values[4];
airColorR.B = values[5];
airColorM.R = values[6];
airColorM.G = values[7];
airColorM.B = values[8];
directPart.R = values[9];
directPart.G = values[10];
directPart.B = values[11];
return(true);
}
private static MyColor ScaleColor(ref MyDColor tot)
{
double scale = -45.0;
var color = new MyColor(
(byte)(255 * Math.Max(0.0, Math.Min(1.0, 1 - Math.Exp(scale * tot.R)))),
(byte)(255 * Math.Max(0.0, Math.Min(1.0, 1 - Math.Exp(scale * tot.G)))),
(byte)(255 * Math.Max(0.0, Math.Min(1.0, 1 - Math.Exp(scale * tot.B)))));
return(color);
}
private static MyDColor InverseScaleColor(ref MyColor color)
{
double scale = -45.0;
MyDColor tot = new MyDColor()
{
R = Math.Log(1.0 - color.R / 255.0) / scale,
G = Math.Log(1.0 - color.G / 255.0) / scale,
B = Math.Log(1.0 - color.B / 255.0) / scale,
};
return(tot);
}
public MyColor SkyColorAtPointDist(GeoPolar2d p, double dist, MyColor ground, double nDotL)
{
double theta = skyColor.GetTheta(p);
MyDColor attenuation = new MyDColor();
MyDColor airColorR = new MyDColor();
MyDColor airColorM = new MyDColor();
MyDColor directPart = new MyDColor();
aerialPers.Value.TryGetValues(dist, ref attenuation, ref airColorR, ref airColorM, ref directPart);
MyColor color = Nishita.CombineForAerialPrespective(ground, theta, nDotL, ambientLight,
ref attenuation,
ref airColorR,
ref airColorM,
ref directPart);
return(color);
}
internal void SkyColorAtPointComputer(double h0, double dist,
out MyDColor attenuation,
out MyDColor airColorR,
out MyDColor airColorM,
out MyDColor directPart)
{
attenuation = ElementLightAP(h0, dist, 0);
airColorR = new MyDColor();
airColorM = new MyDColor();
directPart = new MyDColor();
var hitEarth = Intersect(h0, sinPhiSun, 0);
if (!hitEarth.HasValue || hitEarth.Value < 0)
{
// Air has no color if there is no sunlight
double lmaxP = Intersect(h0, sinPhiSun, H_atmosphere).Value;
double sunAttenuationRbase = TOverBeta(h0, sinPhiSun, lmaxP, H_R);
MyDColor sunAttenuationR = new MyDColor()
{
R = Math.Exp(-BetaR0[(int)Channel.R] * sunAttenuationRbase),
G = Math.Exp(-BetaR0[(int)Channel.G] * sunAttenuationRbase),
B = Math.Exp(-BetaR0[(int)Channel.B] * sunAttenuationRbase),
};
double sunAttenuationM = Math.Exp(-mieScale * BetaM0 * TOverBeta(h0, sinPhiSun, lmaxP, H_M));
// *P_R(theta)
var rayR = new MyDColor()
{
R = BetaR0[(int)Channel.R],
G = BetaR0[(int)Channel.G],
B = BetaR0[(int)Channel.B],
}.Mult(Math.Exp(-h0 / H_R));
// P_M(theta)
var rayM = mieScale * BetaM0 * Math.Exp(-h0 / H_M);
var airColor = Integrate(0, dist, l => ElementLightAP(h0, l, 0));
airColorR = airColor.Mult(sunAttenuationR).Mult(sunAttenuationM).Mult(rayR);
airColorM = airColor.Mult(sunAttenuationR).Mult(sunAttenuationM).Mult(rayM);
directPart = sunAttenuationR.Mult(sunAttenuationM).Mult(attenuation);
}
}
internal static MyColor CombineForAerialPrespective(MyColor ground, double theta, double nDotL, double ambiantLight,
ref MyDColor attenuation,
ref MyDColor airColorR,
ref MyDColor airColorM,
ref MyDColor directPart)
{
var pr = P_R(theta);
var pm = P_M(theta);
var dground = InverseScaleColor(ref ground);
// var ambient = dground.Mult(ambiantLight).Mult(attenuation);
//var direct = dground.Mult(nDotL * 2).Mult(directPart);
//var total = airColorR.Mult(pr).Add(airColorM.Mult(pm)).Add(ambient).Add(direct);
var total = new MyDColor();
total.R = airColorR.R * pr + airColorM.R * pm + (dground.R * ambiantLight * attenuation.R) + (dground.R * nDotL * 2 * directPart.R);
total.G = airColorR.G * pr + airColorM.G * pm + (dground.G * ambiantLight * attenuation.G) + (dground.G * nDotL * 2 * directPart.G);
total.B = airColorR.B * pr + airColorM.B * pm + (dground.B * ambiantLight * attenuation.B) + (dground.B * nDotL * 2 * directPart.B);
return(ScaleColor(ref total));
}