Facing - caraminden/anathema-roguelike GitHub Wiki

Each character has a Facing, this value represents the direction in which that character is looking. A character's Facing determines the area in which is can detect enemies with its Vision. If a character becomes Aware of an enemy using its Vision one of the things it can determine about that enemy is its Facing. If a character knows the Facing of an enemy it can predict that enemy's Field of View, this is represented to the player as an outline of the area inside the Field of View.