/// <summary>
/// Gets a unit sphere from the cache.
/// </summary>
/// <param name="subdivisions">
/// The number of subdivisions.
/// </param>
/// <returns>
/// A unit sphere mesh.
/// </returns>
private static MeshGeometry3D GetUnitSphere(int subdivisions)
{
if (UnitSphereCache.ContainsKey(subdivisions))
{
return UnitSphereCache[subdivisions];
}
var mb = new MeshBuilder(false, false);
mb.AddRegularIcosahedron(new Vector3(), 1, false);
for (int i = 0; i < subdivisions; i++)
{
mb.SubdivideLinear();
}
for (int i = 0; i < mb.positions.Count; i++)
{
var v = mb.positions[i];
v.Normalize();
mb.positions[i] = v;
}
var mesh = mb.ToMeshGeometry3D();
UnitSphereCache[subdivisions] = mesh;
return mesh;
}