AI: Difference between revisions

==Alarm behavior - "She's everywhere!"==

In order to make AI look more humane, it is a good idea to grant it ability to interact with the world the same way player does. In Oni that means for example to give AI option to use consoles.

:BSL scripting provides a command to make AI go and use a console - '''ai2_doalarm''' ''ai_name/index'' '''number of console'''. This way AI can be told to use any console. But there is a method to make AI character use a console completely on it own.

:In order to utilize those mechanics, there is a need for a console which has ALARM CONSOLE flag set (see [[OBD:BINA/OBJC/CONS]]). In XML this flag has a string '''IsAlarm'''. Such a console then can be used by AI characters without scripting.

:Next, there are Alarm parameters in [[CMBT]] profiles which define AI character's alarm behavior:

:*Search distance - a perimeter around the character where engine checks for any console with ALARM CONSOLE flag. In xml it is named <SearchDistance>.

:*Ignore distance - a perimeter around AI character where this AI character (which is currently executing alarm behavior) acknowledges enemies. Enemies outside of this perimeter are ignored by the AI character. In xml it is named <EnemyIgnoreDistance>.

:*Attack distance - a perimeter around AI character where this AI character (which is currently executing alarm behavior) temporarily stops its run for the console and attacks enemies if they are within this range and AI character sees them with central vision field. In xml it is named <EnemyAttackDistance>.

:*Damage threshold - in xml named <DamageThreshold>. Time interval for which AI character keeps awareness of enemy who attacked it. If this enemy crosses Attack distance perimeter, AI temporarily stops its run for alarm and immediately attacks this enemy (does not have to see him with central vision field).

:*Fight timer - in xml called <FightTimer>, duh. Numer of frames for which AI character should fight with the enemy before it attempts to resume its run for alarm.

:Logic for alarm running is set, now how to trip it? There are three ways how to make character run and use a console without BSL. the console must have ALARM CONSOLE flag set and ust lie within Search distance perimeter:

:*in [[CMBT]]: If no gun behavior set to "Run for Alarm". In xml it is RunForAlarm string inside <NoGunBehavior>. By setting this parameter, AI character will attempt to run and use a console when it does not have a loaded weapon or spare clips in inventory (then it reload and continues shooting). If there is no alarm console nearby, AI will switch to Melee.

:*in [[CMBT]]: Behaviors (Long, Medium, Short, MediumRetreat, LongRetreat) can be set to be "Run for Alarm". DO NOT confuse with "Run for alarm If no gun" behavior! This behavior is never used in retail Oni, the reason probably being the fact if there is no useable console within Alarm search distance radius, then AI character simply stands and stares even when enemy is visible with central vision field.

:*In [[CHAR]]: Lost behavior "FindAlarm" - When AI character makes definite contact with enemy and then enemy manages to escape, AI executes "Lost" behavior (see "Pursuit of enemy" section). This behavior is typically set as ReturnToJob, but FindAlarm works well with no known issues. If alarm console is not found within search distance, AI returns to its job.

:A couple of notes regarding AI character:

:*in order to register enemy and attack her/him pre-emptively, AI character must have "HostileThreatDefinite" timer set in ONCC file to some value over 60 (Oni runs 60 frames per second).

:*"If no gun" behavior "Run for Alarm" can get glitched. "Alarm enemy attack distance" is set to some value, let's say 100. Now when AI character runs for alarm and enemy attacks it, then if in this [[CMBT]] profile there is not set melee override for range at least 100 (via melee override or by heving "Melee" set in corresponding combat ranges, see section [[#Combat behavior part 1 : "Hokey religions and ancient weapons..."|Combat behavior]]), chances are AI will get stuck in a loop trying to reach both enemy and console at the same time.

:*Similar issue can happen with combat behavior Run For Alarm as well, but this time problems rise when this combat behavior Run For Alarm is set as Short range behavior.

:A couple of notes regarding target console:

:*Console must be in "activated" mode. If console is in deactivated or used modes, alarm behavior will not be executed.

:*Console must be directly accessible. Oni AI cannot use consoles in order to open path to get to the point of interest (target console in this case). Target console must be directly accessible. Still, it can be directly accessible across the whole level ^_^.

:As already mentioned, Alarm behavior can be tripped by BSL command ai2_doalarm. In that case alarm behavior is executed but this time console is set by command instead of being looked for via Search distance. Also, by ai2_doalarm AI can be made to use any console, not only those with ALARM CONSOLE flag.

Modding hints: ability of AI to use consoles is an excellent tool for increasing a challenge.

:*Beware of setting Run For Alarm combat behavior as close range one. Such a setup causes glitches.

:*On the other side, combat behavior Run For Alarm can be deliberately used to add element of surprise to fights. In [[CMBT]] profile, set Run For Alarm as either Medium or MediumRetreat behavoir, then shorten interval between <MediumRange> and <ShortRange> values (for example set "Medium Range" to 60 and "Short Range" to 59). Thanks to this setup, AI can attempt to find an alarm console while still being capable of fighting even when no alarm is nearby.

:*In [[BSL]] a modder can easily distinguish if console was used by player or AI thanks to '''chr_is_player('''ai_name''')''' function. All what is required is a BSL function being triggered when console is used. Here is example where console triggers a function called '''console1_used''':

  if(chr_is_player(ai_name))

  {

  *Some code in case player used the console*

  }

  else

  {

  *Some code in case AI used the console*

  }

:*Other way of using alarm mechanics is to create a feeling of cooperation - player has to achieve something and in order to do so, an AI driven sidekick who goes after needed console and uses it is required.

:*In extreme case, AI character can be even made to though the level on it own, moving from one console to another. That can be used to create chasing levels - AI character has to activate a certain number of consoles while player is required to stop this AI character from doing so. Thanks to Alarm behavior the task of tripping consoles can be fully completed by AI, no scripting needed. such a setup is on the one side prone to possible AI glitches, but on the other side can add element of randomness and increase replayability.