AI: Difference between revisions

==Combat behavior part 1 : "Hokey religions and ancient weapons..."==

Of course an action game like Oni is not complete without guns blazing and fists flying through the air. But combat in real life is usually very fickle and everything has to be considered. How can Oni AI possibly deal with such a complex task?

:Oni AI character has to have definite awareness of the enemy in order to actively attack him. Alert level of the AI character when in combat mode is Combat (duh). Definite awareness can be achieved by these ways:

:*Enemy was seen by this AI character's central vision field.

:*AI character is made to attack the enemy by [[BSL]] function '''ai2_attack'''.

:*AI character was hurt by the enemy, be it melee or gun damage.

Once combat mode is entered, then as long as HostileThreatDefinite timer for this enemy does not reach zero, AI character will always know exact location of this enemy and will attempt to attack it. The moment HostileThreatDefinite timer is depleted, AI character loses the privilege of knowing exact location, awareness decerases from definite to strong and AI character either switches from combat mode with this enemy to pursuit mode with this enemy (see section [[#Pursuit of enemy alias "I will find you..."|Pursuit of enemy]]) or, in case of other enemy being present in central vision field, picks this new enemy as a target to attack and keeps old enemy in strong (and later weak and later forgotten) awareness.

:Since generally method of combat depends on distance between participants, some sort of spacing is needed. Oni uses system of three ranges around AI, called combat ranges. See picture on right. Perimeters of these ranges can be set in [[CMBT]] profile.

:These ranges work as "triggers" to make the AI character execute various behaviors, based on enemy's position. Moreover, Oni can distinguish between states when enemy entered specified range or exited specified range. So all range possibilities in Oni which can be assigned some combat behavior are:

:*Short - enemy is closest to the AI character

:*Medium - enemy is approaching the AI character and crossed from Long Range into Medium Range.

:*Long - enemy is approaching the AI character and starts from the Long Range.

:*Medium Retreat - enemy is retreating from Short Range into Medium Range.

:*Long Retreat - enemy is retreating from Medium Range into Long Range.

:Well of course nothing is perfect and in Oni there is a bit of an issue with proper switching between combat ranges, so Long and Medium ranges are used only once at the beginning of enemy approach. Only Short, Medium Retreat and Long Retreat ranges are used on regular basis in a combat. Even when enemy runs into Long Retreat and goes back to to medium range, engine does not switch AI behavior range to Medium, but (contrary to its name) to Medium Retreat.

OK, we have positioning, now for actual behaviors AI character can be set to execute within these ranges. There are fourteen possible combat behaviors (in brackets are xml strings):

:*None (None) - simply nothing

:*Stare (Stare) - AI character stands and stares, does not even rotate to face enemy

:*Hold and fire (HoldAndFire) - AI character stands still and fires a weapon. If this character does not have a weapon, then she/he switches to melee.

:*Firing charge (FiringCharge) - AI character runs towards the enemy and fires a weapon. If this character does not have a weapon, then she/he switches to melee.

:*Melee (Melee) - AI character always uses melee, even when she/he holds a loaded weapon.

:*Barabbas shoot (BarabasShoot) - AI character stands still and fires a weapon with hardcoded three seconds pause between shots. If this character does not have a weapon, then he switches to melee. If this character meets certain conditions, she/he can start health regeneration. More detailed info about regeneration mechanics [[Barabas' regeneration| can be read HERE.]]

:*Barabbas advance (BarabasAdvance) - AI character runs towards the enemy and fires a weapon with '''secondary fire mode''' (as if player pressed right button). If this character does not have a weapon, then she/he switches to melee. If this character meets certain conditions, she/he can start health regeneration. More detailed info about regeneration mechanics [[Barabas' regeneration| can be read HERE.]]

:*Barabbas melee (BarabasMelee) - AI character uses melee, even with loaded weapon in hand. If this character meets certain conditions, she/he can start health regeneration. More detailed info about regeneration mechanics [[Barabas' regeneration| can be read HERE.]]

:*Superninja fireball (SuperNinjaFireball) - Mukade's long range behavior. With this behavior AI cannot shoot weapons and cannot use melee, simply runs towards the enemy. However, if weapon is held, character can use melee (probably something from weapon melee override). AI character is occasionally teleported into the back of the enemy (AnimType 222 - Teleport In) if distance to enemy is greater than 100. It seems like it should work regularly once distance to enemy exceeds 100, but in reality something screws this teleport mechanics ^_^. Anyway, to add more to this behavior AI executes two special TRAM animations:

:**AnimType 224 - Ninja Fireball, after the use there is 20 seconds pause before then this [[TRAM]] is used again.

:**AnimType 225 - Ninja Invisible, grants 10 second cloak, after the use there is 20 seconds pause before this TRAM is used again.

::'''IMPORTANT''' There is an annoying problem with this behavior. When it is called, it checks character's position height-wise from the origin of the game world (coordinates 0,0,0) and if the height is below 550, this character is automatically moved to height 550 (which in almost all cases means death by falling).

:*Superninja advance (SuperNinjaAdvance) - Mukade's medium range behavior. With this behavior AI cannot shoot weapons and cannot use melee, simply runs towards the enemy. However, if weapon is held, character can use melee (probably something from weapon melee override). This behavior gives ability to use AnimType 225 - Ninja Invisible which grants 10 seconds invisibility. In order to be able to use this ability, AI has to be at least 50 (or 40?) units far from its enemy. Cooldown for this special technique is 20 seconds. Again, annoying '''over 550 height check''' is present.

:*Superninja melee (SuperNinjaMelee) - Mukade's short range behavior. With this behavior AI cannot shoot weapons but can use melee. This behavior gives ability to use AnimType 225 - Ninja Invisible which grants 10 seconds invisibility. In order to be able to use this ability, AI has to be at least 50 (or 40?) units far from its enemy. Cooldown for this special technique is 20 seconds. This behavior also grants ability to teleport away from enemy to certain distance (around 100 units) if any one of these conditions is met:

:**This character get thrown by any throw.

::Again, annoying '''over 550 height check''' is present.

:*Run for alarm (RunForAlarm) - see section [[#Alarm behavior - "She's everywhere!"|Alarm behavior]].

:*Mutant Muro melee (MutantMuroMelee) - AI character is only allowed to melee, will not fire weapons. This behavior casts chenille (overpower effect) on the user. Of course in order to see visible effect character has to have set <HasDaodanPowers> to 1 in [[ONCC]]. This chenille mode does not grant damage overpower effect, melee attacks deal their usual damage. If ONCC has set both <HasDaodanPowers> and <HasSuperShield> to 1, the chenille mode called by this behavior grants super shield.

::Chenille mode lasts forever if it is not terminated either via BSL or by AI character performing a [[TRAM]] which has a DisableShield flag. After 10 seconds interval, chenille is turned back on. Another specialty of this behavior is automatic backwards evasion move when about 35 points of damage or a throw are applied on the AI character. Chenille mode is turned off if this AI character switches to some other combat behavior because the enemy moved to some other combat range.

:*Mutant Muro thunderbolt (MuroThunderbolt) - Upon initial contact AI chracter turns on chenille mode and runs towards enemy. If chenille mode is turned off, then until definite awareness of the enemy is lost this behavior will not cast chenille mode again. This behavior also allows the AI character to use special long range attack - chracter turns off chenille, goes into AnimState 69 (Thunderbolt) and loops special TRAM animation of AnimState 69 (Thunderbolt) and AnimType 231 (Muro_Thunderbolt). That lasts for 10 seconds. Then AI makes 5 seconds pause during which it runs towards enemy. If after those 5 seconds AI character is still executing Mutant Muro thunderbolt behavior, AI character starts again looping the TRAM animation which has AnimType 231 and AnimState 69.

::This behavior's special (looping TRAM animation) lasts even when enemy enters some other combat range with the exception of Short range. If enemy enters Short range while the looped animation is running, the loop is forced to stop and AI character starts using Short range behavior.

Modding hints: Combat behaviors can have severe impact on AI performance in a fight but can as well hinder the AI

:*Remember: due to a glitch, crucial behaviors for combat are Short, MediumRetreat and LongRetreat. Long And Medium are used only at the beginning of an ecounter.

:*In general, use common sense. There is little use in setting Firing Charge as Short range behavior.

:*Barabbas Shoot and Barabbas Melee behaviors have access to heal ability which can be a great asset for introducing mutants or stronger enemy units. However, remember that Barabbas Shoot limits rate of fire to one shot per three seconds.

:*Barabbas Advance is the only behavior which allows AI to fire a weapon with secondary fire mode. However the behavior is quite glitched (AI character often looks away and fires stray shots). Still, with proper gun and proper setup it can be useable for boss fights.

:*Superninja's behaviors sound excellent for cunning enemy units, however annoying check for character's minimal allowed height from world origin and subsequent forced repositions severely impact these behaviors' usefulness. Despite the height limit, with deliberately designed level which is uplifted enough on purpose, the behavior will not cause random AI character repositioning. Then it can be used to its fullest.

::One other important thing about these behaviors - if AI character does not have required [[TRAM]]s in her/his [[TRAC]], the AI character can get stuck if she/he uses these behaviors.

:*If there is no console with ALARM CONOSLE flag within Alarm sarch distance, then behavior "Run For Alarm" will make AI enemy just stand and stare. Set this behavior with caution and consider using a workaround where medium and short combat ranges have very close diameters with Run For Alarm being MediumRetreat behavior, so Run For Alarm behavior is executed only for a brief amount of time as AI practically immediately switches to LongRetreat. However even one frame is enough because if alarm is found, AI character is requested to perform alarm run which can override combat (see section [[#Alarm behavior - "She's everywhere!"|Alarm behavior]] for more info).

:*MutantMuro melee can be used to create tricky foes which have to be eliminated from distance because if player comes up close, these enemies will turn on their (super)shield and won't put it away (no TRAM with DisableShield flag). That means player has to put some distance between him and these AI characters in order to make them disable the shield.

:*MutantMuro thunderbolt should NEVER be assigned to Short range behavior as that will negatively affect its special attack. Set it as LongRetreat or MediumRetreat. This kind of behavior (with proper [[TRAM]]s) can be used to create foes who will perform special long range attack if player tries to keep a distance. This ranged attack does not have to be the same as Muro's tractor thunderbolt. For quick example, AI character can be made to fire a sort of aggressive plasma beam.

==Combat behavior part 2 : "Guns or not, my fists are hot."==