/// <summary>
/// Test whether this sphere penetrates another, and by how far.
/// </summary>
/// <param name="other"></param>
/// <returns>The distance by which my sphere penetrates the other, or -1 if they don't touch</returns>
public float PenetrationBy(Sphere other)
{
// dist between cell centres (squared)
float distSq = Vector3.LengthSq(this.Centre - other.Centre);
// sum of the two radii
float radii = this.Radius + other.Radius;
// If the dist from centre to centre is smaller than the sum of the radii we are in contact
if (distSq < (radii * radii))
{
// return the penetration distance
return (radii - (float)Math.Sqrt(distSq));
}
return -1;
}
/// <summary>
/// Combine two bounding spheres to create a single sphere enclosing both.
/// Overload accepting a Sphere as argument
/// </summary>
public void CombineBounds(Sphere add)
{
CombineBounds(add.Centre, add.Radius);
}
/// <summary>
/// Test whether this sphere penetrates another.
/// Faster than PenetrationBy() but doesn't return penetration distance (use if dist not needed)
/// </summary>
/// <param name="other"></param>
/// <returns>The distance by which my sphere penetrates the other, or -1 if they don't touch</returns>
public bool IsPenetrating(Sphere other)
{
// dist between cell centres (squared)
float distSq = Vector3.LengthSq(this.Centre - other.Centre);
// sum of the two radii
float radii = this.Radius + other.Radius;
// If the dist from centre to centre is smaller than the sum of the radii we are in contact
if (distSq < (radii * radii))
return true;
return false;
}
/// <summary>
/// Return the SQUARE of the distance between this sphere's centre and another's
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public float CentreToCentreSq(Sphere other)
{
return Vector3.LengthSq(this.Centre - other.Centre);
}