public Normal3 Sample(Random random)
{
/// Get Point uniformly on Disc
double angle = random.NextDouble() * 2 * Math.PI;
double r = random.NextDouble() + random.NextDouble();
r = r < 1 ? r : 2 - r;
double u = r * Math.Cos(angle);
double v = r * Math.Sin(angle);
/// Raise Disc point to Hemisphere
double w = Math.Sqrt(1 - u * u - v * v);
Normal3 uDirection = Normal3.AnyPerpendicular(Orientation);
Normal3 vDirection = Normal3.Perpendicular(Orientation, uDirection);
return(new Normal3(uDirection * (float)u + vDirection * (float)v + Orientation * (float)w));
}
public Normal3 Sample(Random random)
{
/// Compute Height
double theta = Math.Pow((random.NextDouble() - 0.5d) * Math.PI, Exponent);
double r = Math.Cos(theta);
double w = Math.Sin(theta);
/// Compute u and v
double angle = random.NextDouble() * 2 * Math.PI;
double u = r * Math.Cos(angle);
double v = r * Math.Sin(angle);
/// Transform to Orientation
Normal3 uDirection = Normal3.AnyPerpendicular(Orientation);
Normal3 vDirection = Normal3.Perpendicular(Orientation, uDirection);
return(new Normal3(uDirection * (float)u + vDirection * (float)v + Orientation * (float)w));
}
