Constructs a
Focususing the first threerealarguments as the x, y, and z-coordinates ofposition, and the fourth through the sixth argument as the x, y, and z-coordinates ofdirection. dist specifies the distance of theFocusfrom the plane of projection, ang the angle of rotation, which affects which direction is considered to be “up”, and ax the major axis to which theFocusis aligned.
Resets an existing
Focus. Corresponds to the constructor above.