/// <summary>
/// Calculates latitude/longitude for given screen coordinate.
/// </summary>
public virtual void PickingRayIntersection(
int screenX,
int screenY,
out Angle latitude,
out Angle longitude)
{
if (m_ProjectionMatrix == null || m_ViewMatrix == null)
{
latitude = Angle.FromDegrees(0);
longitude = Angle.FromDegrees(0);
return;
}
Vector3d v1 = Vector3d.Empty;
v1.X = screenX;
v1.Y = screenY;
v1.Z = viewPort.MinZ;
v1.Unproject(viewPort, m_ProjectionMatrix, m_ViewMatrix, m_WorldMatrix);
Vector3d v2 = Vector3d.Empty;
v2.X = screenX;
v2.Y = screenY;
v2.Z = viewPort.MaxZ;
v2.Unproject(viewPort, m_ProjectionMatrix, m_ViewMatrix, m_WorldMatrix);
Vector3d p1 = new Vector3d(v1.X, v1.Y, v1.Z);
Vector3d p2 = new Vector3d(v2.X, v2.Y, v2.Z);
double a = (p2.X - p1.X) * (p2.X - p1.X) + (p2.Y - p1.Y) * (p2.Y - p1.Y) + (p2.Z - p1.Z) * (p2.Z - p1.Z);
double b = 2.0 * ((p2.X - p1.X) * (p1.X) + (p2.Y - p1.Y) * (p1.Y) + (p2.Z - p1.Z) * (p1.Z));
double c = p1.X * p1.X + p1.Y * p1.Y + p1.Z * p1.Z - _worldRadius * _worldRadius;
double discriminant = b * b - 4 * a * c;
if (discriminant <= 0)
{
latitude = Angle.NaN;
longitude = Angle.NaN;
return;
}
double t1 = ((-1.0) * b - Math.Sqrt(b * b - 4 * a * c)) / (2 * a);
Vector3d i1 = new Vector3d(p1.X + t1 * (p2.X - p1.X), p1.Y + t1 * (p2.Y - p1.Y), p1.Z + t1 * (p2.Z - p1.Z));
Vector3d i1t = SMath.CartesianToSpherical(i1.X, i1.Y, i1.Z);
Vector3d mousePointer = i1t;
latitude = Angle.FromRadians(mousePointer.Y);
longitude = Angle.FromRadians(mousePointer.Z);
}
// Compute Sun geocentric cartesian position given actual position on the globe,
// heading, elevation and sun distance
public static Vector3d GetGeocentricPosition(Vector3 position, Angle heading, Angle elevation, double sunDistance)
{
// Untransformed sun pos from globe center
Vector3 sun = SMath.SphericalToCartesian(elevation.Degrees, SMath.RadiansToDegrees(Math.PI - heading.Radians), sunDistance);
// Now transform it to current location
Vector3 pos = SMath.CartesianToSpherical(position.X, position.Y, position.Z);
Matrix sunTrans = Matrix.Identity;
sunTrans *= Matrix.Translation(0, 0, pos.X); // radius pos
sunTrans *= Matrix.RotationY((float)Math.PI / 2 - pos.Y); // lat pos
sunTrans *= Matrix.RotationZ(pos.Z); // lon pos
sun.TransformCoordinate(sunTrans);
return(new Vector3d(-sun.X, -sun.Y, -sun.Z));
}
