Determines if a creature perceives another creature using its Spot skill vs. the other creature's Hide skill and its Listen skill vs. the other creature's Move Silently skill.
Constants
Constant
Description
PERCEPTION_HEARD
Heard (Listen beats Move Silently), no line of sight.
PERCEPTION_HEARD_AND_NOT_SEEN
Heard only (Hide beats Spot, Listen beats Move Silently). Usually arouses suspicion for a creature to take a closer look.
PERCEPTION_NOT_HEARD
Not heard (Move Silently beats Listen), no line of sight.
PERCEPTION_NOT_SEEN
Not seen (Hide beats Spot), too far away to heard or magically silcenced.
PERCEPTION_NOT_SEEN_AND_NOT_HEARD
Neither seen nor heard (Hide beats Spot, Move Silently beats Listen).
PERCEPTION_SEEN
Seen (Spot beats Hide), too far away to heard or magically silcenced.
PERCEPTION_SEEN_AND_HEARD
Both seen and heard (Spot beats Hide, Listen beats Move Silently).
PERCEPTION_SEEN_AND_NOT_HEARD
Seen only (Spot beats Hide, Move Silently beats Listen). Usually causes a creature to take instant notice.