Conditional Loot Functions - More RPG Library

More RPG Library provides conditional loot functions that allow you to create loot tables compatible with optional mod dependencies. These functions gracefully handle items that may not be registered.

Overview

Conditional loot comes in two forms:

Conditional Item Function - Replaces an item with another if it exists (with fallback)
Conditional Item Entry - Adds an item only if it exists (no fallback)

Both approaches ensure your loot tables remain functional even when optional mods are not installed.

Conditional Item Function

Replaces a base item with a conditional item if the conditional item is registered. If not registered, the base item is used as a fallback.

Syntax

loot_table.json

{
  "type": "minecraft:item",
  "name": "minecraft:diamond",
  "functions": [
    {
      "function": "more_rpg_classes:conditional_item",
      "conditional_item": "your_mod:jade_gem"
    },
    {
      "function": "minecraft:set_count",
      "count": {
        "min": 1,
        "max": 4
      }
    }
  ]
}

Parameters

conditional_item

Type: String (Item ID)
Required: Yes The item to use if it exists in the registry.

"conditional_item": "other_mod:custom_item"

How It Works

Item Check

The function checks if conditional_item is registered in the game.

Replace or Keep

If the item exists: Replace the base item with the conditional item
If the item doesn’t exist: Keep the base item (fallback)

Apply Additional Functions

Any subsequent functions (like set_count) are applied to the resulting item.

Examples

Cross-Mod Gem Drops

loot_table.json

{
  "type": "minecraft:chest",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "minecraft:item",
          "name": "minecraft:diamond",
          "functions": [
            {
              "function": "more_rpg_classes:conditional_item",
              "conditional_item": "custom_gems:ruby"
            },
            {
              "function": "minecraft:set_count",
              "count": {
                "min": 1,
                "max": 3
              }
            }
          ]
        }
      ]
    }
  ]
}

Result:

If custom_gems:ruby is registered: 1-3 rubies
If not registered: 1-3 diamonds

Optional Material with Enchantment

loot_table.json

{
  "type": "minecraft:item",
  "name": "minecraft:iron_ingot",
  "functions": [
    {
      "function": "more_rpg_classes:conditional_item",
      "conditional_item": "better_metals:steel_ingot"
    },
    {
      "function": "minecraft:set_count",
      "count": 5
    }
  ]
}

Use this function when you want to provide better rewards if a mod is installed, but still want to give something if it’s not.

Conditional Item Entry

Adds an item to the loot pool only if it exists. If the item isn’t registered, nothing is added to the loot table (no fallback).

Syntax

loot_table.json

{
  "type": "more_rpg_classes:conditional_item",
  "item": "your_mod:jade_gem",
  "count": {
    "type": "minecraft:uniform",
    "min": 1,
    "max": 3
  }
}

Parameters

item

Type: String (Item ID)
Required: Yes The item to add if it exists.

count

Type: Number provider
Required: No
Default: 1 Number of items to drop. Can be a constant or a number provider.

weight

Type: Integer
Required: No
Default: 1 Loot table weight for this entry.

quality

Type: Integer
Required: No
Default: 0 Loot table quality (affects luck-based selection).

Examples

Optional Bonus Items

loot_table.json

{
  "type": "minecraft:chest",
  "pools": [
    {
      "rolls": 2,
      "entries": [
        {
          "type": "minecraft:item",
          "name": "minecraft:gold_ingot",
          "weight": 10
        },
        {
          "type": "more_rpg_classes:conditional_item",
          "item": "rare_materials:adamantite_ore",
          "weight": 5,
          "count": {
            "type": "minecraft:uniform",
            "min": 1,
            "max": 2
          }
        }
      ]
    }
  ]
}

Result:

If rare_materials:adamantite_ore exists: Chance to get 1-2 adamantite ore
If not: Only gold ingots can drop

Multiple Optional Items

loot_table.json

{
  "type": "minecraft:chest",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "more_rpg_classes:conditional_item",
          "item": "custom_gems:ruby",
          "weight": 10,
          "count": 3
        },
        {
          "type": "more_rpg_classes:conditional_item",
          "item": "custom_gems:sapphire",
          "weight": 10,
          "count": 3
        },
        {
          "type": "more_rpg_classes:conditional_item",
          "item": "custom_gems:emerald_shard",
          "weight": 5,
          "count": 1
        }
      ]
    }
  ]
}

If none of the conditional items are registered, the loot pool will be empty. Consider including at least one vanilla fallback entry.

With Vanilla Fallback

loot_table.json

{
  "type": "minecraft:chest",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "more_rpg_classes:conditional_item",
          "item": "special_weapons:legendary_sword",
          "weight": 1
        },
        {
          "type": "minecraft:item",
          "name": "minecraft:diamond_sword",
          "weight": 9
        }
      ]
    }
  ]
}

Binding Spells to Items

The bind_spell_from_pools function allows you to bind random spells from spell pools to any item, turning it into a spell container.

Syntax

loot_table.json

{
  "type": "minecraft:item",
  "name": "minecraft:diamond_sword",
  "functions": [
    {
      "function": "more_rpg_classes:bind_spell_from_pools",
      "spell_pools": ["#wizards:arcane", "#wizards:frost"],
      "count": 1
    }
  ]
}

Parameters

spell_pools

Type: Array of strings
Required: Yes Spell pools or specific spells to bind. Use # prefix for tags.

count

Type: Number provider
Required: No
Default: 1 Number of spells to bind to the item.

chance

Type: Number provider (0.0 - 1.0)
Required: No
Default: 1.0 (100%) Probability of applying the spell binding.

Examples

Enchanted Sword with Spell

loot_table.json

{
  "type": "minecraft:item",
  "name": "minecraft:diamond_sword",
  "functions": [
    {
      "function": "more_rpg_classes:bind_spell_from_pools",
      "spell_pools": ["#wizards:fire"],
      "count": 1
    },
    {
      "function": "minecraft:enchant_randomly"
    }
  ]
}

Multi-Spell Staff

loot_table.json

{
  "type": "minecraft:item",
  "name": "wizards:arcane_staff",
  "functions": [
    {
      "function": "more_rpg_classes:bind_spell_from_pools",
      "spell_pools": ["#wizards:arcane", "#wizards:frost", "#wizards:fire"],
      "count": {
        "type": "minecraft:uniform",
        "min": 2,
        "max": 3
      }
    }
  ]
}

Chance-Based Spell Binding

loot_table.json

{
  "type": "minecraft:item",
  "name": "minecraft:golden_sword",
  "functions": [
    {
      "function": "more_rpg_classes:bind_spell_from_pools",
      "spell_pools": ["#paladins:holy"],
      "count": 1,
      "chance": 0.25
    }
  ]
}

If the item is not already a spell container, this function will convert it into one.

Comparison Table

Feature	Conditional Item Function	Conditional Item Entry
Entry Type	`minecraft:item` with function	`more_rpg_classes:conditional_item`
Fallback	Yes (base item)	No
Use Case	Better rewards if mod exists	Optional bonus items
If item missing	Returns base item	Returns nothing
Best For	Primary loot with upgrades	Secondary/bonus loot

Implementation Reference

Conditional Item Function

net.more_rpg_classes.util.loot.ConditionalItemLootFunction

Function ID: more_rpg_classes:conditional_item

Conditional Item Entry

net.more_rpg_classes.util.loot.ConditionalItemEntry

Entry Type: more_rpg_classes:conditional_item

Bind Spell Function

net.more_rpg_classes.util.loot.BindSpellFromPoolsLootFunction

Function ID: more_rpg_classes:bind_spell_from_pools

Get Started

Core Features

Spell Schools

Guides

Documentation Index

​Overview

​Conditional Item Function

​Syntax

​Parameters

​conditional_item

​How It Works

​Examples

​Cross-Mod Gem Drops

​Optional Material with Enchantment

​Conditional Item Entry

​Syntax

​Parameters

​item

​count

​weight

​quality

​Examples

​Optional Bonus Items

​Multiple Optional Items

​With Vanilla Fallback

​Binding Spells to Items

​Syntax

​Parameters

​spell_pools

​count

​chance

​Examples

​Enchanted Sword with Spell

​Multi-Spell Staff

​Chance-Based Spell Binding

​Comparison Table

​Implementation Reference

​Conditional Item Function

​Conditional Item Entry

​Bind Spell Function

Build docs developers (and LLMs) love

Overview

Conditional Item Function

Syntax

Parameters

conditional_item

How It Works

Examples

Cross-Mod Gem Drops

Optional Material with Enchantment

Conditional Item Entry

Syntax

Parameters

item

count

weight

quality

Examples

Optional Bonus Items

Multiple Optional Items

With Vanilla Fallback

Binding Spells to Items

Syntax

Parameters

spell_pools

count

chance

Examples

Enchanted Sword with Spell

Multi-Spell Staff

Chance-Based Spell Binding

Comparison Table

Implementation Reference

Conditional Item Function

Conditional Item Entry

Bind Spell Function