public void SetViewCenter(HorizontalCoordinate viewCenterCoord)
{
ViewCenterVector = viewCenterCoord.ToVector();
HorizontalCoordinate vertAxisCoord = new HorizontalCoordinate(viewCenterCoord.Azimuth + Angle.Right, Angle.Zero);
vertAxis = vertAxisCoord.ToVector();
horzAxis = Vector3.Cross(this.ViewCenterVector, vertAxis);
}
public static HorizontalCoordinate From(Matrix matrix)
{
// Invert the matrix
matrix = Matrix.Invert(matrix);
// Transform (0, 0, -1) -- the vector extending from the lens
Vector3 zAxisTransformed = Vector3.Transform(-Vector3.UnitZ, matrix);
// Get the horizontal coordinates
HorizontalCoordinate horzCoord = From(zAxisTransformed);
// Find the theoretical HorizontalCoordinate for the transformed +Y vector if the phone is upright
Angle yUprightAltitude = Angle.Zero;
Angle yUprightAzimuth = Angle.Zero;
if (horzCoord.Altitude.Degrees > 0)
{
yUprightAltitude = Angle.Right - horzCoord.Altitude;
yUprightAzimuth = Angle.Straight + horzCoord.Azimuth;
}
else
{
yUprightAltitude = Angle.Right + horzCoord.Altitude;
yUprightAzimuth = horzCoord.Azimuth;
}
Vector3 yUprightVector = new HorizontalCoordinate(yUprightAzimuth, yUprightAltitude).ToVector();
// Find the real transformed +Y vector
Vector3 yAxisTransformed = Vector3.Transform(Vector3.UnitY, matrix);
// Get the angle between the upright +Y vector and the real transformed +Y vector
double dotProduct = Vector3.Dot(yUprightVector, yAxisTransformed);
Vector3 crossProduct = Vector3.Cross(yUprightVector, yAxisTransformed);
crossProduct.Normalize();
// Sometimes dotProduct is slightly greater than 1, which
// raises an exception in the angleBetween calculation, so....
dotProduct = Math.Min(dotProduct, 1);
Angle angleBetween = Angle.FromRadians(Vector3.Dot(zAxisTransformed, crossProduct) * Math.Acos(dotProduct));
horzCoord.Tilt = angleBetween;
return(horzCoord);
}
public void GetAngleOffsets(HorizontalCoordinate objectCoord, ref Angle horzAngle, ref Angle vertAngle)
{
Vector3 objectVector = objectCoord.ToVector();
Vector3 horzObjectCross = Vector3.Cross(objectVector, -horzAxis);
Vector3 vertObjectCross = Vector3.Cross(objectVector, vertAxis);
horzObjectCross.Normalize();
vertObjectCross.Normalize();
double x = Vector3.Dot(horzObjectCross, vertAxis);
double y = Vector3.Dot(horzObjectCross, this.ViewCenterVector);
horzAngle = -Angle.ArcTangent(y, x);
x = Vector3.Dot(vertObjectCross, horzAxis);
y = Vector3.Dot(vertObjectCross, this.ViewCenterVector);
vertAngle = -Angle.ArcTangent(y, x);
}
// Called external to update HorizontalCoordinate
public void Update(Time time, GeographicCoordinate location)
{
bool needsUpdate = false;
if (!this.Time.Equals(time))
{
this.Time = time;
needsUpdate = true;
OnTimeChanged();
}
if (!this.Location.Equals(location))
{
this.Location = location;
needsUpdate = true;
}
if (needsUpdate)
{
this.HorizontalCoordinate = HorizontalCoordinate.From(this.EquatorialCoordinate, this.Location, this.Time);
}
}