View Source Ecspanse.Resource behaviour (ECSpanse v0.10.0)

Resources are global components that don't belong to any entity.

They are best used for configuration, global state, statistics, etc.

Resources are defined by invoking use Ecspanse.Resource in their module definition.

Options

:state - a list with all the resource state struct keys and their initial values (if any). For example: [:player_count, max_players: 100]
:export_filter - :none | :resource - indicates if the resource should be exported. Defaults to :none. See Ecspanse.Snapshot for details.
- :none - no filter. The resource will be exported.
- :resource - the resource will not be exported.

There are two ways of providing the resources with their initial state:

At compile time, when invoking the use Ecspanse.Resource, by providing the :state option.

defmodule Demo.Resources.PlayerCount do
 use Ecspanse.Resource, state: [player_count: 0, max_players: 100]
end

At runtime when creating the resources from specs: t:Ecspanse.Resource.resource_spec()
```
Ecspanse.Command.insert_resource!({Demo.Resources.Lobby, [max_players: 50]})
```

There are some special resources that are created automatically by the framework:

Ecspanse.Resource.FPS - tracks the frames per second.

Note
Resources can be created, updated or deleted only from synchronous systems.

Summary

Implemented Callbacks

fetch()

Fetches the resource. It has the same functionality as Ecspanse.Query.fetch_resource/1, but it may be more convenient to use in some cases.

Types

resource_spec()

A resource_spec is the definition required to create a resource.

Callbacks

validate(resource)

Optional callback to validate the resource state.

Functions

debug()

Utility function. Returns all the resources and their state.

Implemented Callbacks

fetch()

@callback fetch() :: {:ok, component :: struct()} | {:error, :not_found}

Fetches the resource. It has the same functionality as Ecspanse.Query.fetch_resource/1, but it may be more convenient to use in some cases.

Implemented Callback
This callback is implemented by the library and can be used as such.

Examples:

    {:ok, %Demo.Resources.Config{} = resource} = Demo.Resources.Config.fetch()

    # it's the same as:

    {:ok, %Demo.Resources.Config{} = resource} = Ecspanse.Query.fetch_resource(Demo.Resources.Config)