Feature Request: Make ship AI a separate equippable item for NPCs

[Du4lity5151]

Why?

Currently, the game's AI is fixed functionality that acts the same regardless of the ship. While in many cases this is fine, allowing it to be a separate equippable item (e.g. core\assets\items\ai\imperialAI\imperialAI.json) with parameters that define it's accuracy, firing frequency, preferred distance from player, etc. can open possibilities for adjustable difficulty levels, as well as unique ship behavior characteristics from different ships, especially within the context of factions having ships whose AI behaves distinctly from other factions.

How?

Make moduleName\assets\items\ai\nameAI\nameAI.json a valid example, whose config file may look something like this, but may include more parameters for more detailed behavior definition:

{ "fixedGunAccuracy": 0.5, "firingFrequency": 0.7, "preferredDistanceFromPlayer": 100 }

Where:

• fixedGunAccuracy refers to a value between 0 and 1 that determines the percentage of it's aiming accuracy with fixed guns
• firingFrequency refers to a value between 0 and 1 that determines the percentage of how willingly it will fire, 1 being always, whenever it is aimed at the player
• preferredDistanceFromPlayer refers to how much of a unit measurement of distance in which it will try to achieve before firing at the player

Equipping on NPC
It should not be an item the player can pick up or buy, but can be equipped on an NPC within a config file such as systemsConfig.json. Example:
{ "hull": "core:imperialBig", "items": "core:fixedGun core:fixedShotGun core:mediumArmor+core:heavyArmor core:shield+core:bigShield core:imperialAI", "density": 3 }

[BenjaminAmos]

In my mind, items are classified as such because they can be bought and sold in-game. If it is an intrinsic property of the ship itself then it should probably be specified as part of a ship's HullConfig. If it can be configured at runtime but is not a direct commodity then that gets a bit more complex.

I agree that the AI parameter config files you suggest would be a good approach. There definitely should be a more configurable way to specify and tweak a ship's AI pilot. There is an open question of how we expose this though, as it very much ties into how ships spawning is handled in the code right now.

For context, I should probably briefly explain how things are handled currently. Every SolShip has an assigned Pilot, which issues commands to control the ship's movements. For the player, this is UiControlledPilot. NPC ships use AiPilot. The main places where AiPilot instances are created in-game are:

• MercenaryUtils.java:44 (when spawning mercenaries)
• GalaxyFiller.java:111 (when spawning random wandering ships)
• GalaxyFiller.java:234 (when creating a guard)
• PlanetObjectsBuilder.java:359 (when spawning planetary guards)
• PlanetObjectsBuilder.java:383 (when spawning planetary ships)
• ChunkFiller.java:199 (when spawning random wandering ships)
• MazeBuilder.java:169 (when spawning random ships in mazes)

I mention this primarily for my own reference but you may find it useful as well.

For each of the scenarios above, there needs to be a way to pass the AI configuration data through to those points in the code. It will likely require some re-architecting that needs more looking into. My current line of thinking is that we add a layer on-top of HullConfig (i.e. the files you see in assets/ships/someShip.json), which is purely responsible for ship spawning variants (ShipSpawnConfig). These would be referenced in places where we current reference HullConfig at the moment. It may look something like the following:

{
    "hull": "core:imperialBig",
    "items": "core:someGun*2",
    "ai": {
        "movementBehaviour": {
            "type:" "guard"
        },
        "shootingBehaviour": {
            "type": "builtin",
            "fixedGunAccuracy": 0.5,
            "firingFrequency": 0.7,
            "preferredDistanceFromTarget": 100
        },
        "attackBehaviour": {
             "type": "guard"
        }
    }
}

(This would be similar to, if not an outright replacement of, mainStationConfig.json.)

[Du4lity5151]

In my mind, items are classified as such because they can be bought and sold in-game. If it is an intrinsic property of the ship itself then it should probably be specified as part of a ship's HullConfig. If it can be configured at runtime but is not a direct commodity then that gets a bit more complex.

Although initially the intent of this feature was to make AI more varied within the game content rather than be a player-equippable item, someone within the Discord server did mention the possibility of implementing it as an item you would equip onto your mercenaries to modify their behavior, which could be another interesting application of this feature. Therefore, this could be a viable use case for making it available for purchase or loot, but making something that can only be equipped by NPCs still may be a challenge depending on the codebase.

[Du4lity5151]

If a mercenary's AI is unequipped or does not ship with one, it would most likely stop turning, moving, and shooting. For immersion reasons, I would personally prefer if it freezes mid-flight while drifting in space, to pressure the player to equip another AI before it drifts further away, but an alternative that sacrifices immersion for ease of play would be to set default behavior to cancel out any motion upon unequipping AI.

If shipped with multiple AIs, e.g.
"mercenaries": [ { "hull": "core:imperialMedium", "items": "3*rep core:smallShield core:imperialAI core:minerAI", "money": 200 } ]
We could give the player flexibility to choose which AI suits their needs and either set a default AI, e.g.
"mercenaries": [ { "hull": "core:imperialMedium", "items": "3*rep core:smallShield core:imperialAI core:minerAI", "defaultai": "core:imperialAI", "money": 200 } ]
or leave the AIs unequipped by default and let the player choose which one to use if not specified.