(Call of Duty-esque) Directional Indicator

Hi! I'm at a complete loss on this. I would like to implement a circular direction indicator, like in Call of Duty's hit indication. It would work by getting two points, the 'player' position, and the 'target' position. It would require allowing more than one target position. (Contrary to the image, Origin would have to include rotation as well as position, for the direction indicators to be correctly facing.

 

http://docs.unity3d.com/ScriptReference/Vector3.Angle.html

use that to get the angle between the origin facing and the incoming fire vector (top down view so ignore the z(?) axis), then use that angle to rotate the gui element...

 

Or if you know the world position of the thing that shot you, you can then use WorldToScreenPoint/WorldToViewportPoint and rotate the gui towards that screen position.

 

do they work if the world position isn't within the camera's view i.e. being shot in the back etc.? I've always assumed they didn't...

 

Yes, The Z component of the returned Vector3 is the position in world units from the camera. If this is <0 the object is behind the camera, otherwise it is infront