public static PolarPoint ToPolar(Point point)
{
if (PolarCache == null)
{
PolarCache = CreatePolarCache();
}
int quadrant = 0;
int x = point.X;
int y = point.Y;
if (y < 0)
{
x = -x;
y = -y;
quadrant = 128;
}
if (x < 0)
{
int tmp = -x;
x = y;
y = tmp;
quadrant += 64;
}
int shift = Calc.HighestBit((uint)(x | y) >> PolarCacheBits);
PolarPointB polarB = PolarCache[y >> shift, x >> shift];
return(new PolarPoint(polarB.Distance << shift, (byte)(polarB.Angle + quadrant)));
}
static PolarPointB[,] CreatePolarCache()
{
PolarPointB[,] cache = new PolarPointB[PolarCacheRadius, PolarCacheRadius];
for (int y = 0; y < PolarCacheRadius; ++y)
{
for (int x = 0; x < PolarCacheRadius; ++x)
{
cache[y, x].Distance = Convert.ToInt16(Math.Round(Math.Sqrt(Calc.Sq(x) + Calc.Sq(y))));
if (y > 0 || x > 0)
{
cache[y, x].Angle = Angle.AtanB(new Point(x, y));
}
else
{
cache[y, x].Angle = 0;
}
}
}
return(cache);
}
