public override Color GetPixel(int x, int y)
{
double theta = (double)x / m_Size.Width * DMS.TAU; //longitude
double phi = (double)y / m_Size.Height * DMS.HALFTAU; //angle down from north pole (latitude-ish)
Point2D pt = new Point2D(theta, phi);
//"unroll" by adding TAU * number of turns to theta, (and then back it off one)
while( DMS.TAU * pt.Y > m_x * pt.X )
{
pt.X += DMS.TAU;
}
pt.X -= DMS.TAU;
//undo our spiral by rotating it clockwise
pt.Theta -= m_alpha;
//scale it so that we're referencing the stretched textStrip in it's native resolution
pt.Scale(m_stretchedSize.Width / (m_n * m_y));
//unstretch it
double horiz = pt.X * 2.0 / m_stretchedSize.Width; // 0 ... 2
horiz -= 1.0; // -1 ... 1
horiz *= m_maxStretched; // -m_maxStretched ... m_maxStretched
horiz = unstretch(horiz); // -m_maxUnstretched ... m_maxUnstretched
horiz /= m_maxUnstretched; // -1 ... 1
horiz += 1.0; // 0 ... 2
horiz *= 0.5 * m_textStripeSize.Width; // 0 ... textwidth
pt.X = horiz;
//wind our strip back up so we can reference the right pixel in the source
while (pt.X >= m_Source.Width)
{
pt.X -= m_Source.Width;
pt.Y += m_textStripeSize.Height;
}
if (pt.Y >= m_Source.Height || pt.Y < 0.0 || pt.X < 0.0 )
return m_Blank;
return m_Source.GetPixel((int)pt.X, (int)pt.Y);
}
public Color GetSpherePixel(Point3D point)
{
if (mSourceType == DMSImageType.Equirectangular)
{
//latitude and longitude are pulled straight from spherical coordinates of the 3d pooint
double longitude = point.Theta / DMS.TAU;
double latitude = point.Phi / DMS.HALFTAU; //but really 0 is at the north pole.
if (longitude < 0.0 ) longitude += 1.0;
Point2D EquirectangularLocation = new Point2D( longitude, latitude );
return GetPixel(EquirectangularLocation);
}
else
{
// we can get the location on a mirror ball image from the spherical coordinates by taking the sin of phi.
Point2D MirrorBallLocation = Point2D.FromPolar(Math.Sin(point.Phi/2.0), point.Theta);
//the coordinates are from -1 to 1, we need to convert them to 0 to 1
MirrorBallLocation += new Point2D(1, 1);
MirrorBallLocation.Scale(0.5);
return GetPixel(MirrorBallLocation);
}
}