Method for displaying a virtual object on a display screen

摘要

The position of an object is represented on a screen by an icon. The position of a reference point on the object is determined in world coordinates which are transformed into screen coordinates. These are used to draw the reference point and the object onto the screen. If the contents of the screen is subsequently to be redrawn with a different orientation (eg on selection of a different direction as up, or on selection of "heading up" mode), the screen coordinates of the reference point are transformed into new screen coordinates.