private void ComputeKey(int level, Envelope itemEnv)
{
double quadSize = DoubleBits.PowerOf2(level);
//double quadSize = pow2.power(level);
_pt.X = Math.Floor(itemEnv.MinX / quadSize) * quadSize;
_pt.Y = Math.Floor(itemEnv.MinY / quadSize) * quadSize;
_env.Initialize(_pt.X, _pt.X + quadSize, _pt.Y, _pt.Y + quadSize);
}
/// <summary>
/// Computes the exponent for the largest power of two
/// less than the absolute value of the argument.
/// In other words, finds the value n such that
/// 2ˆn <= abs(num) < 2ˆ(n+1)
/// </summary>
/// <param name="num"></param>
/// <returns>The exponent.</returns>
public static int Exponent(double num)
{
num = Math.Abs(num);
double log = Math.Log(num);
double log2 = log / LOG_2;
int exp = (int)Math.Floor(log2);
int exp2 = DoubleBits.Exponent(num);
if (exp != exp2)
{
//System.out.println(DoubleBits.toBinaryString(num));
//System.out.println(num + " pow2 mismatch: " + exp + " DoubleBits: " + exp2);
double pow2exp = DoubleBits.PowerOf2(exp);
double pow2exp2 = DoubleBits.PowerOf2(exp2);
//System.out.println(pow2exp + " pow2exp2 = " + pow2exp2);
}
return(exp);
}