Resource Location

Minecraft's resource location is often used as an identifier for items but also for locations of asset files like models and textures. It consists of two strings: a domain and a path. The domain is usually a mod id. The path is a name (for items) or a path (for files). A Resource Location can be represented like this: domain:path. A Resource Location can not contain any characters. Upper case letters are not allowed. Numbers are allowed. Underscore is allowed.

Creating a Resource Location

There are two ways to do that:

Using the net.minecraft.util.ResourceLocation constructor (this class is auto imported since version 0.4.0)
- new ResourceLocation("domain:path")
- new ResourceLocation("domain", "path")
- new ResourceLocation("path") (defaults to minecraft domain)
Using the resource() game object handler (acts like a global method)
- resource("domain:path")
- resource("domain", "path")
- resource("path") (defaults to the pack id specified in the run config (see here))

We can see that both methods are mostly the same except that the game object handler defaults to the pack id instead of minecraft. This way is the preferred way.

Example

groovy

// the following 2 lines are equal
def rl1 = resource("groovyscript", "path/to/file") // groovyscript:path/to/file
def rl2 = resource("groovyscript:path/to/file") // groovyscript:path/to/file
// the domain defaults to the pack id if not specified
def rl3 = resource("furnace") // packid:furnace

In GroovyScript there usually exist overrides where you can directly insert mod id and path without creating a ResourceLocation.

Converting to file path

In the following .../.minecraft/ is the instance folder.
.minecraft/resources/ is the root resource folder (requires Resource Loader mod). Resources can be in any valid path as long as minecraft knows about it. Since version 0.4.0 the root folder may also be .minecraft/groovy/assets/. Resource packs are also a valid way to load resources.
The whole path is composed of

the root path
the domain (mod id)
the path (of the resource location)

Formatted: rootPath/domain/path

Examples

We use .minecraft/resources as the root here.

Resource Location	refers to File path
`minecraft:textures/gui/button.png`	`.minecraft/resources/minecraft/textures/gui/button.png`
`textures/gui/button.png`	`.minecraft/resources/minecraft/textures/gui/button.png`
`thaumcraft:research/SOME_RESEARCH.json`	`.minecraft/resources/thaumcraft/research/SOME_RESEARCH.json`

Model files

In model or blockstate json files you may also find resource locations. Lets take assets/minecraft/models/block/andesite.json for example (assets being the root folder). In there you will find

json

{
  "parent": "block/cube_all",
  "textures": {
    "all": "blocks/stone_andesite"
  }
}

Here "block/cube_all" and "blocks/stone_andesite" are both resource locations. So you might think the texture is located in assets/minecraft/blocks/stone_andesite, but that is not the case. The real path is assets/minecraft/textures/blocks/stone_andesite.png. The reason for that is that minecraft knows it should point to a texture and prepends textures/ and appends .png to the path. It's similar for "parent": "block/cube_all" except it points to another model.

Other uses

Resource locations are also used as identifiers for game registry entries for example items.
When you use the item bracket handler you do something like item('minecraft:iron_ingot'). Yes 'minecraft:iron_ingot' is a resource location, except it doesn't point to a resource. For game objects like items the resource location is also referred to as the registry name.

Warning

Note that you can't use item('iron_ingot'). This is disabled by GroovyScript. You must always input the full registry name.