What I'm trying to reproduce is kind of what Jet Pack Joyride has in place. When an enemy, projectile, or anything harmful is incoming, an alert is shown on the screen in the direction the harmful thing is coming.
In this case, the alerts need are happening anywhere 360 degrees. How do I do this? Of course the alerts are going to appear on the HUD but how do I make them appear in the direction that the enemy is/will appear?