)
Scope to draw multiple things in screen space of a camera.
If you draw 2D coordinates (i.e. (x,y,0)) they will be projected onto a plane approximately [2*near clip plane of the camera] world units in front of the camera (but guaranteed to be between the near and far planes).
The lower left corner of the camera is (0,0,0) and the upper right is (camera.pixelWidth, camera.pixelHeight, 0)