The Spark Plug Tools Dynamic Vision Cone plug-in generates a dynamic, customizable
vision cone that can be resized by arc angle and distance from the origin,
and then affected further by dynamic scene colliders.
The resulting cone can conform to dynamic and static scene geometry by specifying
a collider mask, and each vision cone in a scene can be set to use different
parameters for collision tests based on application or gaming need.
This solution was used extensively in the multi-platform mobile and tablet game Plight of the Zombie (link)
More info and live demo
