Camera.WorldToViewportPoint

function WorldToViewportPoint (position : Vector3) : Vector3

Description

Transforms position from world space into viewport space.

Viewport space is normalized and relative to the camera. The bottom-left of the camera is (0,0); the top-right is (1,1). The z position is in world units from the camera.

// Finds out whether target is on the left or right side of the screen
var target : Transform;

function Update () {
var viewPos = camera.WorldToViewportPoint (target.position);
// viewport coordinates range from zero to one
if( viewPos.x > 0.5 )
print ("target is on the right side!");
else
print ("target is on the left side!");
}