This is a mouse position detector. It has the same function as the mouse x and mouse y blocks, except that the mouse x and mouse y blocks cannot detect mouse position if the mouse is offstage, while this can. USES: In many 3d games, the amount that the player turns is determined by mouse movement, but when the mouse moves offstage, the movement system is messed up. Maybe this could be used to reduce the effect of this problem. Press space to turn on a faster one that only reads mouse x position in range of fullscreen. Its purpose is for 3d games.