public DiskLight(Transformation objectToWorld, float radius = 1, SampledSpectrum spectrum = null)
: base(objectToWorld, spectrum)
{
_radius = radius;
_normal = ObjectToWorld.TransformNormal(new Vector3(0, -1, 0)).Normalized();
NSamples = (uint)Math.Max(1, _radius / 4f);
}
public override Point Sample(float u1, float u2, out Normal ns)
{
var z = MathUtility.Lerp(u1, _zMin, _zMax);
var t = u2 * _phiMax;
var p = new Point(_radius * MathUtility.Cos(t), _radius * MathUtility.Sin(t), z);
ns = Normal.Normalize(ObjectToWorld.TransformNormal(new Normal(p.X, p.Y, 0)));
if (ReverseOrientation)
ns *= -1.0f;
return ObjectToWorld.TransformPoint(ref p);
}
public override Point Sample(float u1, float u2, out Normal ns)
{
Point p = new Point(0, 0, 0) + _radius * MonteCarloUtilities.UniformSampleSphere(u1, u2);
ns = Normal.Normalize(ObjectToWorld.TransformNormal(new Normal(p.X, p.Y, p.Z)));
if (ReverseOrientation)
{
ns *= -1.0f;
}
return(ObjectToWorld.TransformPoint(ref p));
}
public override Point Sample(float u1, float u2, out Normal ns)
{
var p = new Point();
MonteCarloUtilities.ConcentricSampleDisk(u1, u2, out p.X, out p.Y);
p.X *= _radius;
p.Y *= _radius;
p.Z = _height;
ns = Normal.Normalize(ObjectToWorld.TransformNormal(new Normal(0, 0, 1)));
if (ReverseOrientation)
{
ns *= -1.0f;
}
return(ObjectToWorld.TransformPoint(ref p));
}
