Easy See is an easy to use, scalable package, you can use it to easily see objects within the visual field (set objects tag), the field of vision can define your own, you can set the distance, angle and direction.
Click here to buy Easy See on the Unity Asset Store.
Click here to view WebGL Demo.
How to use?
"EasySee.cs" script add to GameObject.
set "select mode" to 3D or 2D
Vision(Range of you can see)
Angle(Range of angles)
Event(When the target appears in the visible range (tag target is to player),the method has been executed)
When selected already has easysee script GameObject show Visualization Perspective editor
Find glowing sphere
There are many spheres, they hide in the dark, you need to find them.
Holding a flashlight in your hand, when the ball is in the light, it will glow appears, continue to look to the next until all found.
Fleeing enemy vision
There are many enemies nearby, can't be seen by them, when them found you, they will be angry and discoloration, and always follow you, until you get rid of them.