Introduction To Behavior Packs
This page explains how to reproduce the example from https://learn.microsoft.com/en-us/minecraft/creator/documents/behaviorpack?view=minecraft-bedrock-stable with Allay.
Before building your first Add-On for Minecraft: Bedrock Edition, you will need to create a pack to hold your custom content. There are two types of packs that a creator can make: resource packs and behavior packs. A behavior pack is a folder structure that contains files that drive entity behaviors, loot drops, spawn rules, items, recipes, and trade tables. This tutorial covers how behavior packs are created and how to add behaviors to an in-game cow entity to make it aggressive.
.
├── allay.toml
└── src/
├── BP/
+ │ └── entities/
+ │ └── cow.json
├── RP/
├── SP/
└── WT/
Every entity’s behaviors are defined in its JSON file that lives inside the code that makes Minecraft work. You’re going to create a new cow behavior file that Minecraft will use instead of its usual “vanilla” one.
{
"format_version": "1.16.0",
"minecraft:entity": {
"description": {
"identifier": "minecraft:cow",
"is_spawnable": true,
"is_summonable": true,
"is_experimental": false
},
"component_groups": {
"minecraft:cow_baby": {
"minecraft:is_baby": {},
"minecraft:scale": {
"value": 0.5
},
"minecraft:ageable": {
"duration": 1200,
"feed_items": "wheat",
"grow_up": {
"event": "minecraft:ageable_grow_up",
"target": "self"
}
},
"minecraft:behavior.follow_parent": {
"priority": 6,
"speed_multiplier": 1.1
}
},
"minecraft:cow_adult": {
"minecraft:experience_reward": {
"on_bred": "Math.Random(1,7)",
"on_death": "query.last_hit_by_player ? Math.Random(1,3) : 0"
},
"minecraft:loot": {
"table": "loot_tables/entities/cow.json"
},
"minecraft:behavior.breed": {
"priority": 3,
"speed_multiplier": 1.0
},
"minecraft:breedable": {
"require_tame": false,
"breed_items": "wheat",
"breeds_with": {
"mate_type": "minecraft:cow",
"baby_type": "minecraft:cow",
"breed_event": {
"event": "minecraft:entity_born",
"target": "baby"
}
}
},
"minecraft:interact": {
"interactions": [
{
"on_interact": {
"filters": {
"all_of": [
{
"test": "is_family",
"subject": "other",
"value": "player"
},
{
"test": "has_equipment",
"domain": "hand",
"subject": "other",
"value": "bucket:0"
}
]
}
},
"use_item": true,
"transform_to_item": "bucket:1",
"play_sounds": "milk",
"interact_text": "action.interact.milk"
}
]
}
}
},
"components": {
"minecraft:is_hidden_when_invisible": {},
"minecraft:type_family": {
"family": [
"cow",
"mob"
]
},
"minecraft:breathable": {
"total_supply": 15,
"suffocate_time": 0
},
"minecraft:navigation.walk": {
"can_path_over_water": true,
"avoid_water": true,
"avoid_damage_blocks": true
},
"minecraft:movement.basic": {},
"minecraft:jump.static": {},
"minecraft:can_climb": {},
"minecraft:collision_box": {
"width": 0.9,
"height": 1.3
},
"minecraft:nameable": {},
"minecraft:health": {
"value": 10,
"max": 10
},
"minecraft:hurt_on_condition": {
"damage_conditions": [
{
"filters": {
"test": "in_lava",
"subject": "self",
"operator": "==",
"value": true
},
"cause": "lava",
"damage_per_tick": 4
}
]
},
"minecraft:movement": {
"value": 0.25
},
"minecraft:despawn": {
"despawn_from_distance": {}
},
"minecraft:behavior.float": {
"priority": 0
},
"minecraft:behavior.panic": {
"priority": 1,
"speed_multiplier": 1.25
},
"minecraft:behavior.mount_pathing": {
"priority": 2,
"speed_multiplier": 1.5,
"target_dist": 0.0,
"track_target": true
},
"minecraft:behavior.breed": {
"priority": 3,
"speed_multiplier": 1.0
},
"minecraft:behavior.tempt": {
"priority": 4,
"speed_multiplier": 1.25,
"items": [
"wheat"
]
},
"minecraft:behavior.follow_parent": {
"priority": 5,
"speed_multiplier": 1.1
},
"minecraft:behavior.random_stroll": {
"priority": 6,
"speed_multiplier": 0.8
},
"minecraft:behavior.look_at_player": {
"priority": 7,
"look_distance": 6.0,
"probability": 0.02
},
"minecraft:behavior.random_look_around": {
"priority": 9
},
"minecraft:leashable": {
"soft_distance": 4.0,
"hard_distance": 6.0,
"max_distance": 10.0
},
"minecraft:balloonable": {},
"minecraft:rideable": {
"seat_count": 1,
"family_types": [
"zombie"
],
"seats": {
"position": [
0.0,
1.105,
0.0
]
}
},
"minecraft:physics": {},
"minecraft:pushable": {
"is_pushable": true,
"is_pushable_by_piston": true
},
"minecraft:conditional_bandwidth_optimization": {},
"minecraft:behavior.nearest_attackable_target": {
"priority": 2,
"must_see": true,
"reselect_targets": true,
"within_radius": 25.0,
"entity_types": [
{
"filters": {
"test": "is_family",
"subject": "other",
"value": "player"
},
"max_dist": 32
}
]
},
"minecraft:behavior.melee_attack": {
"priority": 3
},
"minecraft:attack": {
"damage": 3
}
},
"events": {
"minecraft:entity_spawned": {
"randomize": [
{
"weight": 95,
"trigger": "minecraft:spawn_adult"
},
{
"weight": 5,
"add": {
"component_groups": [
"minecraft:cow_baby"
]
}
}
]
},
"minecraft:entity_born": {
"add": {
"component_groups": [
"minecraft:cow_baby"
]
}
},
"minecraft:entity_transformed": {
"remove": {},
"add": {
"component_groups": [
"minecraft:cow_adult"
]
}
},
"minecraft:ageable_grow_up": {
"remove": {
"component_groups": [
"minecraft:cow_baby"
]
},
"add": {
"component_groups": [
"minecraft:cow_adult"
]
}
},
"minecraft:spawn_adult": {
"add": {
"component_groups": [
"minecraft:cow_adult"
]
}
}
}
}
}
This is that code that, when added to the components section of a cow.json file, turns cows into
aggressive killing machines:
"minecraft:behavior.nearest_attackable_target": {
"priority": 2,
"must_see": true,
"reselect_targets": true,
"within_radius": 25.0,
"entity_types": [
{
"filters": {
"test": "is_family",
"subject": "other",
"value": "player"
},
"max_dist": 32
}
]
},
"minecraft:behavior.melee_attack": {
"priority": 3
},
"minecraft:attack": {
"damage": 3
}
Now allay build the project and export it to Minecraft.