Adding Loot Tables, Spawn Rules & Crafting Recipes

Next, we'll enhance the custom Ghost entity by adding some more basic mechanics to it:

Loot Tables ​

First, we'll make the ghost drop Ectoplasm upon death: create the following file:

{
    "pools": [
        {
            "rolls": 1,
            "entries": [
                {
                    "type": "item",
                    "name": "wiki:ectoplasm",
                    "weight": 1,
                    "functions": [
                        {
                            "function": "set_count",
                            "count": {
                                "min": 1,
                                "max": 3
                            }
                        }
                    ]
                }
            ]
        }
    ]
}

• Loot tables consist of pools. Each pool defines a different set of loot that will be dropped. A pool consists of 3 parts, rolls, entries and conditions. The conditions are optional and won't be covered in this guide.

• The rolls section defines how many times a random entry will be chosen from the following entries object.

• The entries part defines the items from which the loot table can choose. Each roll a new item will be chosen.

• type defines what will be chosen. You can set it to item or loot_table to either chose an item or an different loot table.

• name defines the identifier of the item (with its namespace) that will be selected.

• weight is optional and defines how likely it is, that this item will be selected. If there is more than one item in the entries section, the weight attribute can be used to make the probability of one item more or less likely. If it isn't set, it defaults to 1.

• functions provide a powerful way of customizing the item that will be returned. They can add enchantments to an item, set an item's name or simply setting the number of items that will be dropped. To define the number of items, we use set_count. It takes the count attribute, which sets the maximum and minimum amount of items that will be dropped.

For more information on loot tables, see our extended guide: Loot Tables!

Spawn Rules ​

Next, we'll make the ghost spawn in deserts at night:

{
    "format_version": "1.8.0",
    "minecraft:spawn_rules": {
        "description": {
            "identifier": "wiki:ghost",
            "population_control": "monster"
        },
        "conditions": [
            {
                "minecraft:spawns_on_surface": {},
                "minecraft:brightness_filter": {
                    "min": 0,
                    "max": 7,
                    "adjust_for_weather": true
                },
                "minecraft:difficulty_filter": {
                    "min": "easy",
                    "max": "hard"
                },
                "minecraft:weight": {
                    "default": 80
                },
                "minecraft:herd": {
                    "min_size": 1,
                    "max_size": 3
                },
                "minecraft:biome_filter": {
                    "test": "has_biome_tag",
                    "operator": "==",
                    "value": "desert"
                }
            }
        ]
    }
}

• You already know what format_version does.
• Inside the minecraft:spawn_rules part we define our spawn rules.
• The description defines the basic properties of the file.
  • The identifier is used to define which entity these spawn rules apply to.
  • population_control is used to limit the amount of entities that will be spawned. Once the pool that is defined inside of population_control is full, no more entities will be spawned.
• With conditions we can define rules that limit the spawning of this entity to special cases. We will shortly describe each condition used here, but you can learn more conditions and how to use them here.
  • spawns_on_surface allows the mob to only spawn on surfaces.
  • minecraft:brightness_filter limits the spawning to areas with a lighting level thats between the defined values. If adjust_for_weather is true, the light level decrease during rain and storms will be ignored.
  • minecraft:difficulty_filter defines the difficulty level needed to spawn the entity.
  • weight defines how often this entity will spawn. The higher this value, the more often the mob will spawn.
  • minecraft:herddefines how many entities will be spawned at once.
  • With minecraft:biome_filter we define the biomes in which the entity is able to spawn.

To learn more about spawn rules, take a look at our list of vanilla spawn rules.

Crafting Recipes ​

And finally, as an introduction to recipes, we'll make the Ectoplasm craftable into Ectoplasm Blocks:

{
    "format_version": "1.20.10",
    "minecraft:recipe_shaped": {
        "description": {
            "identifier": "wiki:ectoplasm_block"
        },
        "tags": ["crafting_table"],
        "pattern": [
            // 3×3 grid of Ectoplasm items
            "###",
            "###",
            "###"
        ],
        "key": {
            "#": {
                "item": "wiki:ectoplasm"
            }
        },
        "unlock": [
            {
                "item": "wiki:ectoplasm" // Unlock this recipe when the player acquires an Ectoplasm item
            }
        ],
        "result": {
            "item": "wiki:ectoplasm_block"
        }
    }
}

• format_version is already known.
• With recipe_shaped we define, that each ingredient has a set place in the crafting grid. There are some other types that can be used, you can find more information here.
• Inside description we define the identifier of this recipe, which is the name of the recipe.
• tags is a list of crafting tags which determine the blocks (crafting table, furnace, etc) that are able to use this recipe.
• pattern defines the arrangement of the items inside the crafting grid. Each # represents the item that is set under key. In this case, the whole 3x3 grid has to be filled with "wiki:ectoplasm", our own item. It is possible to define more items, just add an entry to key and set the key to a character, that you can use inside pattern.
• result contains an item, which is set to the item that will be the output of this recipe.

For more information on this topic, visit our page about recipes!

What You Have Learned ​

Your Progress So Far ​

What you've done:

• Setup your pack
• Create a custom item
• Create a custom entity
• Create the entity's loot, spawn rules, and a custom recipe

Congratulations! you have finished the Guide and created your first Add-on. 🎉