private static SphereDistribution CalculateDistribution(int numChildren)
{
// todo: estimate good radius from number
float radius = 2f;
var angles = new PitchYaw[numChildren];
while (!TryCalculateDistributionForRadius(radius, angles))
{
radius *= 1.1f;
}
return(new SphereDistribution(radius, angles));
}
private static bool TryCalculateDistributionForRadius(float radius, PitchYaw[] anglesToFill)
{
var numChildren = anglesToFill.Length;
if (numChildren == 0)
{
return(true);
}
var middleIndex = numChildren / 2 - 1 + numChildren % 2;
var currentIndex = middleIndex;
var pitch = 0f;
while (currentIndex < numChildren)
{
var horizontalCapacity = HorizontalCapacity(radius, pitch);
var pitchStep = PitchStep(radius);
var nextPitch = pitch + pitchStep;
if (nextPitch + pitchStep / 2 > 0.66f * MathHelper.PiOver2)
{
return(false);
}
var localPitchStep = pitchStep / horizontalCapacity;
var yawStep = YawStep(radius, pitch);
var localBorder = Math.Min(currentIndex + horizontalCapacity, numChildren);
if (currentIndex == middleIndex)
{
anglesToFill[currentIndex] = new PitchYaw(0, 0);
currentIndex++;
}
for (int i = currentIndex; i < localBorder; i++)
{
anglesToFill[i] = new PitchYaw(anglesToFill[i - 1].Pitch + localPitchStep, anglesToFill[i - 1].Yaw + yawStep);
}
currentIndex = localBorder;
pitch = nextPitch;
}
for (int i = middleIndex - 1; i >= 0; i--)
{
var opposite = anglesToFill[middleIndex + (middleIndex - i)];
anglesToFill[i] = new PitchYaw(-opposite.Pitch, -opposite.Yaw);
}
return(true);
}
