Vanilla Overrides#
Summary
Extra metadata to define custom merging for any json resource
Required
Only when overriding any vanilla resource (under minecraft namespace)
Example
Replacing iron ingots with iron nuggets for zombies (loot table)
One rough edge of compatibility between data packs are the vanilla namespaced resources. The default game's biomes, loot tables, advancements — these are difficult to override as other packs might clash causing a loss of behavior. We have solved this problem by integrating a custom merging solution into Weld.
Weld is a tool to help merge data and resource packs in an efficient manner. Similar to how the game automatically merges tag files, Weld allows you to define extra metadata to define how you would like your JSON-type files to merge. This allows you to define an override which is compatible with other weld-enabled packs!
Note
The goal of Weld is to preserve the original author's intent with their modification/creation of the file being merged.
Metadata#
Smithed metadata is stored within the __smithed__ element of the JSON file. Here, you can define how you want to inject your data into the vanilla resource. This is done through a set of rules which are defined in the rules element.
Note
Any extra fields, such as the __smithed__ field, will be ignored by the game when loaded. This allows you to define a valid loot table file while also being able to customize is when weld is used on your pack.
{
// Fields from `minecraft:blocks/dirt`
"__smithed__": {
"rules": [
{
"type": "append",
"target": "pools",
"source": {
"value": {
"rolls": 1,
"bonus_rolls": 0,
"entries": [
{
"type": "minecraft:item",
"name": "minecraft:iron_ingot"
}
]
}
}
}
]
}
}
Note
We use comments in our json blocks here but they will not work in-game.
Here, we define a list of rules which apply multiple adjustments to the loot table. In this example, we define an append rule which targets the original pools field and appends a new entry defined by the source field. This will result in a loot table with a new pool that will drop an iron ingot.
It's pretty common to define your intended resource in the vanilla namespace, then use the __smithed__ rule to define how you want to merge into the vanilla resource when welded. This allows you to have the intended behavior if your pack is used without weld, a really important feature.
Examples#
The simplest usage: appending into pools
The most common use case of welding for the purposes of this convention is appending a new pool or entry into a vanilla loot table. This example adds a pool that drops iron_nuggets into the zombie loot table.
{
"type": "minecraft:entity",
"pools": [
{
"rolls": 1,
"entries": [
{
"type": "minecraft:item",
"functions": [
{
"function": "minecraft:set_count",
"count": {
"type": "minecraft:uniform",
"min": 0,
"max": 2
},
"add": false
},
{
"function": "minecraft:looting_enchant",
"count": {
"type": "minecraft:uniform",
"min": 0,
"max": 1
}
}
],
"name": "minecraft:rotten_flesh"
}
]
},
{
"rolls": 1,
"entries": [
{
"type": "minecraft:item",
"name": "minecraft:iron_ingot"
},
{
"type": "minecraft:item",
"name": "minecraft:carrot"
},
{
"type": "minecraft:item",
"name": "minecraft:potato",
"functions": [
{
"function": "minecraft:furnace_smelt",
"conditions": [
{
"condition": "minecraft:entity_properties",
"predicate": {
"flags": {
"is_on_fire": true
}
},
"entity": "this"
}
]
}
]
}
],
"conditions": [
{
"condition": "minecraft:killed_by_player"
},
{
"condition": "minecraft:random_chance_with_looting",
"chance": 0.025,
"looting_multiplier": 0.01
}
]
},
// This pool is new behavior from TCC
{
"rolls": 1,
"entries": [
{
"type": "item",
"weight": 1,
"name": "minecraft:iron_nugget",
"functions": [
{
"function": "set_count",
"count": {
"min": 0,
"max": 1
}
},
{
"function": "looting_enchant",
"count": {
"min": 0,
"max": 1
}
}
]
}
]
}
],
"random_sequence": "minecraft:entities/zombie",
"__smithed__": {
"rules": [
// This rule then appends our new pool into the vanilla one.
{
"type":"append",
"target":"pools",
"source": {
// We use `reference` source as a way to re-use the json we wrote earlier.
"type":"reference",
"path":"pools[2]"
}
}
]
}
}
Merging into an empty loot table
There might be times where you might be working with an empty resource file where you are adding your own data. In this case, weld will dynamically create the expected object within the JSON as you target it. For example, appending into a non-existant pools field will dynamically create an array.
An example of this behavior can be seen from GM4's bat grenades where add bat leather and gunpowder to bats, a mob that has an empty loot table by default.
Fun Fact
Both GM4's bat grenades and TCC add a rabbit hide equivalent to this loot table!
{
"type": "minecraft:entity",
"pools": [
{
"rolls": 1,
"entries": [
{
"type": "item",
"name": "minecraft:gunpowder",
"functions": [
{
"function": "set_count",
"count": {
"min": 1,
"max": 3
}
}
]
}
]
},
{
"rolls": 1,
"entries": [
{
"type": "item",
"name": "minecraft:rabbit_hide",
"functions": [
{
"function": "set_nbt",
"tag": "{CustomModelData:3420001}"
},
{
"function": "set_name",
"name": {
"translate": "item.gm4.bat_leather",
"fallback": "Bat Leather",
"italic": false
}
},
{
"function": "set_lore",
"lore": [
{
"translate": "text.gm4.bat_leather.1",
"fallback": "Would make for a very strange,",
"italic": true,
"color": "dark_gray"
},
{
"translate": "text.gm4.bat_leather.2",
"fallback": "very tiny jacket",
"italic": true,
"color": "dark_gray"
}
]
}
],
"weight": 1
},
{
"type": "empty",
"weight": 5
}
]
}
],
"random_sequence": "minecraft:entities/bat",
"__smithed__": {
"rules": [
{
"type": "smithed:append",
"target": "pools",
"source": {
"type": "smithed:reference",
"path": "pools[0]"
}
},
{
"type": "smithed:append",
"target": "pools",
"source": {
"type": "smithed:reference",
"path": "pools[1]"
}
}
]
}
}
Replacing a vanilla item with a new / custom one
This simplified loot table is just changing iron_ingot to emerald using the replace rule.
{
"type": "minecraft:entity",
"pools": [
{
"rolls": 1.0,
"entries": [
{
"type": "minecraft:item",
"name": "minecraft:iron_ingot"
}
]
}
],
"random_sequence": "minecraft:entities/zombie_villager",
"__smithed__": {
"rules": [
// Replace `iron_ingot` with `emerald`
{
"type":"replace",
"target": "pools[0].entries[0].name",
"source": {
"value": "minecraft:emerald",
}
}
]
}
}