private int North(HealCoor basin, NeighborHor hor, out int newRing, out int newPixelInRing)
{
newRing = basin.Ring - 1;
var ringFirstP = basin.P - basin.PixelInRing + 1;
var eastIndex = hor == NeighborHor.East ? 1 : 0;
int newP;
switch (basin.NorthCap)
{
case true:
if ((basin.PixelInRing - eastIndex) % basin.Ring == 0)
{
newRing++;
newP = hor == NeighborHor.East ? basin.EastInRing : basin.WestInRing;
}
else
{
newP = basin.P;
ringFirstP -= basin.PixelsCountInRing - 4;
newP -= basin.PixelsCountInRing - 4
+ eastIndex + (basin.PixelInRing - 1) / basin.Ring;
}
break;
case false:
newP = basin.P;
// border between equator and south cap
if (basin.Ring == 3 * _healpixManager.Nside)
{
ringFirstP -= basin.PixelsCountInRing;
newP -= basin.PixelInRing == eastIndex ? 1 : basin.PixelsCountInRing + eastIndex;
}
else
{
var ringFromPole = _healpixManager.RingsCount - basin.Ring + 1;
ringFirstP -= basin.PixelsCountInRing + 4;
newP -= basin.PixelsCountInRing + 4
+ (eastIndex == 1 ? 0 : -1) - (basin.PixelInRing - 1) / ringFromPole;
}
break;
default:
ringFirstP -= basin.PixelsCountInRing;
// exact equator
if (basin.Ring % 2 == 0 && _healpixManager.K > 0)
{
newP = hor == NeighborHor.East ? basin.EastInRing : basin.P;
}
else
{
newP = hor == NeighborHor.East ? basin.P : basin.WestInRing;
}
newP -= basin.PixelsCountInRing; // PixelsCountInRing on equator and first polar cap the same
break;
}
newPixelInRing = newP - ringFirstP + 1;
return(newP);
}
/// <returns>P, from 0</returns>
private int North(HealCoor basin, NeighborHor hor)
{
int newRing, newPixelInRing;
return(North(basin, hor, out newRing, out newPixelInRing));
}
