public virtual Spectrum GetIlluminance(IRayTracer rayTracer, IMaterial material, Point3D point, Vector normal, Vector view)
{
// проверяем что нормали сонаправлены
var xx = Vector.Dot(normal, this.Direction);
if (xx > Constants.Epsilon || point.Z > this.Position.Z)
{
return(new Spectrum());
}
var formFactor = this.GetFormFactor(point);
// если нет расчетных точек, то генерим их на источнике
if (this.LightSamplePoints == null)
{
this.GenerateLightSamplePoints();
}
var result = new Spectrum();
// цикл по всем расчетным точкам на источнике
int raysHited = 0;
foreach (var lightSamplePoint in this.LightSamplePoints)
{
var toLight = lightSamplePoint.Point - point;
var toLightVector = new Vector(toLight, true);
//var toLightRay = new Ray( point, lightSamplePoint.Point );
if (!rayTracer.Occluded(point, toLightVector, Constants.Epsilon, toLight.Length - Constants.Epsilon))
{
// источник косинусный
var cosR = Math.Abs(-Vector.Dot(toLightVector, this.Direction));
result += material.Reflectance.BRDF(toLightVector.Reverse(), normal, view) * cosR;
raysHited++;
}
}
if (raysHited == 0)
{
return(new Spectrum());
}
// усредняем BRDF
result = result / (float)raysHited;
// форм фактор уменьшаяется за счет не попавших лучей
// (float) Math.PI - из ядра уравнения
result = this.Illuminance * result * formFactor * (raysHited / (float)(this.Samples));
//result = result * this.Illuminance / (float)( this.Samples );
return(result);
}
public Spectrum GetIlluminance(IRayTracer rayTracer, IMaterial material, Point3D point, Vector normal, Vector view)
{
var toLight = this.Position - point;
var toLightVector = new Vector(toLight, true);
//var toLightRay = new Ray( point + normal * Constants.Epsilon, this.Position );
if (!rayTracer.Occluded(point + normal * Constants.Epsilon, toLightVector, 0, toLight.Length))
{
return(this.Intensity * material.Reflectance.BRDF(toLightVector, normal, view) / toLight.Length2);
}
else
{
return(new Spectrum());
}
}