Introduction

Description of behavior of all monsters in all mental states, except for danger.

Combat Monsters

This category includes:

1. nosalis
2. aqua_male_small 
3. aqua_female
4. harpy
5. lurker
6. watchman
7. dog 
8. humanimal 
9. wolf
10. cannibal.

Basic Behavior Concept

Unlike human NPCs, monsters do not possess group behavior with role distribution. Each one works on its own. Still, in the uber alert state they will, like human NPCs, synchronize threats and timers among themselves.

1. Disturbed

• This mental state only affects the interest of the monster. It does not play any motions, it simply tries to look toward the threat.

2. Light Alert

• In this state, the monster has to look at the threat, turning if necessary.

3. Alert

• In this state, the monster has to check the location of the threat without alerting others.

4. Uber Alert

• In this state, the monster has to check the location of the threat, alerting others.

Some monsters have a number of quirks associated with their abilities (demons fly, dogs sniff, lurkers hide in holes) which will be described separately.

Basic Behavior Mechanic

Light Alert

Reaction → Threat Inspection → Calming Down

Reaction

1. A monster plays an interest animation directed at the threat.
2. The monster turns towards the threat.
3. Once the motions are over, the monster switches to the next state.

Threat Inspection

• If a threat is nearby, a monster plays the motions of looking around. At the end of the motion, the monster switches to the next state.
• If the threat is not nearby but is visible (raypick), the monster plays the motions of looking at the threat. At the end of the motion, the monster switches to the next state.
• If the threat is not nearby and is not visible, the monster plays the motions of looking around. At the end of the motion, the monster switches to the next state.

Calming Down

Once motions of looking around or looking at the threat are over, the monster will switch to the free state.

Alert                                                                       

Reaction → Looking for Threat → Threat Inspection → Calming Down

Reaction

Same as Reaction in Light Alert.

Looking for Threat

A path to the threat is calculated and the monster begins the movement. While walking along the path, the monster constantly checks the threat’s visibility to keep looking at it.

• If the threat isn’t visible, the monster looks along the path vector and points of interest.
• If the threat is visible, the monster looks toward the threat.
• If the threat is far away, the path to it is not calculated.
• If there is no calculated path to the threat or the threat is too far, this state is skipped.
• When the monster comes close to the threat, it stops and enters the next state.

Threat Inspection

Same as Threat Inspection in Light Alert.

Calming Down

Same as Calming Down in Light Alert.

Uber Alert

Reaction → Looking for Threat → Threat Inspection → Territory Inspection → Calming Down

Reaction

Same as Reaction in Light Alert.

Looking for Threat

Same as Looking for Threat in alert.

Threat Inspection

·        If a threat is nearby, a monster plays the motions of looking around. At the end of the motion, the monster switches to the next state.

·        If the threat is not nearby but is visible (raypick), the monster plays the motions of looking at the threat. After that, the motions of looking around. At the end of the motion, the monster switches to the Calming Down state.

·        If the threat is not nearby and is not visible, the monster plays the motions of looking around. At the end of the motion, the monster switches to the Calming Down state.

Territory Inspection

Current pattern used, where monsters check different locations around the area where the threat was detected.

Calming Down

Same as Calming Down in Light Alert.

Corpse Found

•         The monster perceives the corpse as an uber alert threat. The corpse has an expiration time during which it is perceived as a threat, and once that time elapses it is ignored.

Killing In Sight

Reaction

• The monster that first saw the corpse receives an uber alert visual threat with the position of an initiator.
• The monsters that discovered the corpse reacts according to the standard flow of uber alert sound threats.

Specific Properties of These Monsters 

Smell Mechanic (Dogs/Wolves)

The keen sense of smell lets the entity detect the “trail” and follow it to check it out.

Chain of events:

Reaction → Searching For The Source → Inspection → Repeat or Calming down

Reaction

The entity plays the motions of sniffing and then switches to the state of “Searching For The Source”.

Searching For The Source

The entity moves (pathfind) along the trail, constantly switching between points in the trail’s sequence.

·         If the time specified in the entity’s properties for the search elapses, the entity switches to the Inspection state.

·         If the trail was lost (there are no valid traces within the scent radius), the entity switches to the Inspection state.

Inspection

The entity stops to check the location by sniffing it.

After The Inspection

·         If a “track” is found in the smell radius, the loop repeats, starting with Searching For The Source.

·         If no “track” is found in the smell radius, the entity stops the search and calms down.

The tracks in this case are:

1. Player’s tracks
   1. The player leaves an array of X tracks, each of which lives for Y amount of time (no tracks are left outside of the AI map).
2. A corpse of an entity belonging to the same group, or a corpse of an entity from a group that the assigned NPC leader belongs to (referred to as the “friendly group” below):
1. If the entity from the “friendly group” was killed and the entity’s group did not find out about it, once a certain period of time passes (which can be changed in settings), the corpse becomes a “track” for the group members.
2. If the dead entity from the “friendly group” has already been sniffed or seen by any of the other members of same group, it stops being treated as a new “track” for the whole group.

Particularities: 

·         An entity can only use its sense of smell in the free/disturbed state, i.e. any threat with a state higher than disturbed will take priority over smell.

·         If the entity smells several corpses and the player at once, it chooses the nearest track as its target.

Search Mechanic With a Dog and Leader NPC

If the dog’s leader is alive and is in the uber alert state, AND the dog does not have a unique threat of its own, it uses this mechanic.

Leader Search → Territory Inspection → Repeat

Leader Search

The dog moves toward its leader using sniffing motions. Having reached the leader (an exposed value in meters), the dog switches to Territory Inspection.

Territory Inspection

Same as Territory Inspection in uber alert. 

Once the leader departs and moves further from the dog than a specific distance (an exposed value in meters), the dog switches to Leader Search.

Neutral Monsters

The category includes:

1. rat
2. rabbit
3. deer
4. snake 
5. slave.

Basic Behavior Concept

1. Disturbed

This mental state only affects the interest of the monster. It does not play any motions but simply tries to look toward the threat.

1. Light Alert

In this state, the monster has to stop what it’s doing and look at the threat, turning if necessary.

1. Alert
   1. Some monsters hide in their lairs.
1. In this state, the monster has to get scared and retreat.
2. Uber Alert
   1. Some monsters hide in their lairs.
1. In this state, the monster has to get scared and retreat.
3. Kill In Sight
1. Same as Uber Alert but the monster learns the enemy’s location.
4. Finding A Corpse
1. Same as Uber Alert.

Basic Behavior Mechanic

Light Alert

Same as the Light Alert described above.

Alert And Uber Alert

Safe → Calming down

Safe

Runs away until the timer elapses.

• While running away, it uses the same mechanism as in Species Behavior, i.e. either runs to a particular cover or in the direction opposite to the threat (chosen by the designer).
• While running away, it alerts others.

Calming Down

Once the timer elapses, switches to the free state.

Corpse Found

Treats a corpse as an uber alert threat. The corpse has an expiration time during which it is perceived as a threat, once that time elapses it is ignored.

Kill In Sight

Reaction

• The monster that first saw the corpse receives an uber alert visual threat with a position of the initiator.
• The monsters who found the corpse will react according to the standard flow of uber alert sound threats.

Specific Properties of These Monsters.

Using The Slave Entity

1. In the uni_cannibal subscript, mark the entity as slave.
2. In the state of light alert and above, cease all logic.
3. Use rusik\uni_npc_mental subscript with type=slave to be able to catch the correct end of the fright state.

If the slave goes to sleep or sits down, use the rusik\uni_slave_state subscript to point it out, then the slave will be able to correctly switch to fear from the sitting or prone position and then return back to sitting or prone.

1. Sitting – floor_sit_idle_0
2. Sleeping – monsters\canibal\free_idle_sleep_left_side_0

Other Monsters

The categories include:

1. big_mother
2. aqua_male_big
3. grizly
4. simple_anomaly
5. catfish
6. water worm
7. desert worm
8. nosalis_female 
9. arahind
10. mantabat
11. raven.

Behavior concept

Scripted monsters with unique, entirely scripted behaviors.