/// <summary>
/// Returns intensity (incl. color) of the source contribution to the given scene point.
/// Internal integration support.
/// </summary>
/// <param name="intersection">Scene point (only world coordinates and normal vector are needed).</param>
/// <param name="rank">Rank of this sample, 0 <= rank < total (for integration).</param>
/// <param name="total">Total number of samples (for integration).</param>
/// <param name="rnd">Global (per-thread) instance of the random generator.</param>
/// <param name="dir">Direction to the source is set here (zero vector for omnidirectional source). Not normalized!</param>
/// <returns>Intensity vector in current color space or null if the point is not lit.</returns>
public override double[] GetIntensity(Intersection intersection, int rank, int total, RandomJames rnd, out Vector3d dir)
{
if (rnd == null)
{
return(GetIntensity(intersection, out dir));
}
SamplingState ss;
lock ( states )
{
if (!states.TryGetValue(rnd.GetHashCode(), out ss))
{
ss = new SamplingState(this, rnd);
states.Add(rnd.GetHashCode(), ss);
}
}
// generate a [new] sample:
ss.generateSample(rank, total);
dir = ss.sample - intersection.CoordWorld;
if (Vector3d.Dot(dir, intersection.Normal) <= 0.0)
{
return(null);
}
if (Dim == null || Dim.Length < 3)
{
return(intensity);
}
double dist = dir.Length;
double dimCoef = 1.0 / (Dim[0] + dist * (Dim[1] + dist * Dim[2]));
int bands = intensity.Length;
double[] result = new double[bands];
for (int i = 0; i < bands; i++)
{
result[i] = intensity[i] * dimCoef;
}
return(result);
}
