AI: Difference between revisions

==Congitive possiblities of AI characters ... "COME TO YOUR SENSES!"==

[[File:VisionFields.JPG|thumb|right|alt=Visualization of vision fields.|An example of Blue Striker's central and peripheral vision.]]

When talking about life-like AI, senses have to be taken into an account. Sight, hearing, taste, smell, touch. Unfortunately Oni emulates only sight and hearing.

'''Sight''' is important. Without it the only option for AI to recognize the enemy is to be attacked by the enemy first. Unlike majority of action games, Oni AI characters have two visions:

:*Central - enemy seen by central vision = enemy recognized and attacked.

:*Peripheral - enemy seen by peripheral vision = alert risen to low and AI goes into pursuit mode with given enemy, see '''LINK TO PURSUIT'''

Modding hints - parameters of vision fields are stored in ONCC, under '''<VisionConstants>'''. Central vision field distance has to be greater than peripheral vision field distance, otherwise peripheral vision detection will be somehow broken (it will not detect). Since peripheral vision makes AI pursue the enemy but not attack it, it can be set quite large in order to surprise lousy stealth players. But be warned - nobody likes cheating AI ^_^.

'''Hearing''' is crucial in Oni. Majority of AI character interaction is done via sound system. Oni recognizes these types of sound (in brackets visualization when '''ai2_showsounds''' is set to 1):

:*Unimportant (blue) - is ignored to some extent if alert level of AI is lull, but after some period of time AI will register it.

:*Interesting (green) - causes alert rise to low level.

:*Danger (yellow) - causes alert rise to medium level.

:*Melee (orange) - causes alert rise to medium level but AI reacts a bit differently than in case of Danger sound.

:*Gunfire (red) - causes alert rise to high level.

:For more info about AI alert levels, see section [[#Reactions on stimuli a.k.a. "What was that?!"|Reaction on stimuli]]. These sound types are used by impact effects [[ONIE]] and danger sound type can be set in particle as a "danger radius".

:Modding hints: Sound system and ONIE are mighty tools if modder knows how to use them. Even doors can be attached a sound sphere of any one of those listed above, so a modder can create doors which draw attention (sound type interesting) of nearby AI characters if these doors are manipulated.

:Another example is a workaround for AI to get alerted by dead bodies -

::Set dead particle in ONCC to be one special custom made - this particle will for given time keep emiting custom impact effect. That custom impact effect will have no sound or effect attached, but will be set to be hearable by AI as a gunfire within a large radius (200 units).

==Reactions on stimuli a.k.a. "What was that?!"==

In real life each human being is unique with its reactions. But even then reaction differ - when calm or when nervous or when suspicious, a man does not always react the same way. And what about Oni?

In Oni, reaction on stimulus is based on type of stimulus (see previous section) and on level of AI alert level. Oni AI characters have these alert levels:

:Level of alert can be set via BSL as '''ai2_setalert''' ''ai_name/chr_index'' '''desired level of alert'''. Levels of alert play the role of "behavior modifier". Artificial Intelligence reacts on seen or heard allies/enemies according to its own level of alert. Level of alert can be increased by:

:*hearing a sound which causes rise of alert level (for detailed info read previous section)

:*special rise of alert level from Lull to Low is by enemy being seen by peripheral vision or by enemy causing too many unimportant sounds

:*special rise of alert level to Combat is by being hit by the enemy or by alarm being triggered (see [[OBD:BINA/OBJC/CONS]]) or by script functions '''ai2_tripalarm''', '''ai2_makeaware''' or '''ai2_attack''' (see [[BSL:Functions]]).

:Alert level also affects movement mode of AI driven characters. There are six movement modes - creep, walk, walk_noaim, run, run_noaim, by_alert_level. Those "_noaim" movement modes are forcing AI character to not aim with weapon in case the AI is armed (so AI character walks or runs with the gun in hand but it does not aim with it). Movement mode can be forced via bsl command '''ai2_setmovementmode'''. Alert level affects movement mode only if movement mode is set as '''by_alert_level'''. In that case:

:* Lull and Low alerts use walk_noaim

:* Medium, High and Combat use run

:If patrol path ([[PATR]]) is assigned to a character, it can override movement mode for patrol path purposes and for example force Lull alert character to run with aimed weapon. However, when AI is disturbed and starts pursuit of ally/enemy, movement mode is then chosen by coresponding alert level (given the fact the movement mode is set as '''by_alert_level''').

:Level of alert can decrease via BSL ai2_setalert or with time , exact location of timers unknown (maybe hardcoded).

Next component of AI reaction logic is its '''awareness''' of ally/enemy. Oni recognizes between ally (friendlythreat) and enemy (hostilethreat). Oni AI characters always know whether the disturbance was caused by ally or enemy. That means if player is playing as standard Konoko, shoots and some Striker gets alerted, the Striker knows which character (from [[CHAR]]) shot, which team does the character belong to and according to it the Striker reacts (but more about it later). Oni defines four levels of awareness:

:'''firendlythreat'''

:*Definite - AI is 100% sure where ally stands and ignores him. Is achieved by seeing the ally with central vision field or by being hit by his gun by accident or by being told of its presence by BSL commands ai2_makeaware, ai2_tripalarm or ai2_attack.

:*Strong - AI has strong awareness of ally presence, but cannot pinpoint exact location of the ally character itself. Is caused by all sound types, which are described in previous section. Also if ally is off central vision field and <FriendlyThreatDefiniteTimer> runs out, AI decreases level of awareness from definite to strong.

:*Weak - AI has weak awareness of the character's presence. It is caused either by seeing ally with peripheral vision or by <FriendlyThreatStrongTimer> running out.

:*Forgotten - AI has ecountered some ally, but over time forgot about its presence. <FriendlyThreatWeakTimer> ran out.

:*Definite - AI is 100% sure where enemy stands and will go attack her/him. Is achieved by seeing the enemy with central vision field or by being hit by her/him (or her/his gun) or by being told of its presence by BSL commands ai2_makeaware, ai2_tripalarm or ai2_attack.

:*Strong - AI has strong awareness of enemy presence, but cannot pinpoint exact location of the enemy character itself. Is caused by all sound types, which are described in previous section. If enemy manages to get is off central vision field and <HostileThreatDefiniteTimer> runs out, AI decreases level of awareness from definite to strong. If AI is allowed to investigate, corresponding pursuit behavior is excuted (more about this later).

:*Weak - AI has weak awareness of enemy's presence. It is caused either by seeing enemy with peripheral vision or by <HostileThreatStrongTimer> running out. If AI is allowed to investigate, corresponding pursuit behavior is excuted (more about this later)

:*Forgotten - AI has ecountered some enemy, but over time forgot about its presence. <EnemyThreatWeakTimer> ran out.

:When AI character is freshly spawned, it does not have any contact with other characters (Tabula Rasa). Through sounds and vision, AI learns about presence of other characters and reacts on them according to team affiliation, alert level and awareness. Even when AI character "forgets" about ally/enemy, it does not completely abandon their existence. For example startle behavior when AI character sees an enemy is played only once vs this particular enemy. Even when AI character forgets, it won't play startle animation next time it sees this one enemy, but goes directly attack him.

:Friendly warning: awareness "Forgotten" '''IS NOT''' equal to '''ai2_forget''' command. "Ai2_forget" clears AI character's memory back to Tabula Rasa status.