private IEnumerable <Star> GenerateArms(Random random)
{
int arms = random.Next(MinimumArms, MaximumArms);
float armAngle = (float)((Math.PI * 2) / arms);
int maxClusters = (Size / Spacing) / arms;
for (int arm = 0; arm < arms; arm++)
{
int clusters = (int)Math.Round(random.NormallyDistributedSingle(maxClusters * ClusterCountDeviation, maxClusters));
for (int i = 0; i < clusters; i++)
{
//Angle from center of this arm
float angle = random.NormallyDistributedSingle(0.5f * armAngle * ClusterCenterDeviation, 0) + armAngle * arm;
//Distance along this arm
float dist = Math.Abs(random.NormallyDistributedSingle(Size * 0.4f, 0));
//Center of the cluster
var center = Vector3.Transform(new Vector3(0, 0, dist), Quaternion.CreateFromAxisAngle(new Vector3(0, 1, 0), angle));
//Size of the cluster
var clsScaleDev = ArmClusterScaleDeviation * Size;
var clsScaleMin = MinArmClusterScale * Size;
var clsScaleMax = MaxArmClusterScale * Size;
var cSize = random.NormallyDistributedSingle(clsScaleDev, clsScaleMin * 0.5f + clsScaleMax * 0.5f, clsScaleMin, clsScaleMax);
var stars = new SphereGalaxy(cSize, densityMean: 0.00025f, deviationX: 2, deviationY: 1, deviationZ: 2).Generate(random);
foreach (var star in stars)
{
yield return(star.Offset(center).Swirl(Vector3.UnitY, Swirl));
}
}
}
}
private IEnumerable <Star> GenerateCenter(Random random)
{
//Add a single central cluster
var sphere = new SphereGalaxy(
size: Size * CenterClusterScale,
densityMean: CenterClusterDensityMean,
densityDeviation: CenterClusterDensityDeviation,
deviationX: CenterClusterScale,
deviationY: CenterClusterScale,
deviationZ: CenterClusterScale
);
var cluster = new ClusterGalaxy(sphere,
CenterClusterCountMean, CenterClusterCountDeviation, Size * CenterClusterPositionDeviation, Size * CenterClusterPositionDeviation, Size * CenterClusterPositionDeviation
);
foreach (var star in cluster.Generate(random))
{
yield return(star.Swirl(Vector3.UnitY, Swirl * 5));
}
}