EntitasGenericAddon.Examples.IdFeature

IdFeature

Basic get entity by id functionality example

Dependencies

• Entitas ~1.13.0
• EntitasGenericAddon

Installation

Copy IdFeature folder to your project.

Dll wouldn't work, because this example requires modification of sources to add new Scope to Id component

Usage

First make Id inherit some Scope<T> in IdScopes.cs

// IdScopes.cs
using Entitas.Generic;

namespace Custom.Scripts
{
public partial struct Id
  : Scope<Game>
  //, Scope<Cmd>
{
}

public class Game : IScope { }
public class Cmd : IScope { }
}

Then it becomes possible to get entity by id

public static void IdFeatureExample()
{
  // some init code above

  Lookup_ScopeManager.RegisterAll( );
  var contexts = new Contexts();
  contexts.AddScopedContexts();

  // init id feature right after contexts.AddScopedContexts();
  contexts.IdFeature_InitAuto();

  // get ScopedContext<T>
  var contextGame = contexts.Get<Game>();
  var contextCmd = contexts.Get<Cmd>();

  // use PrimaryEntityIndex through context
  contextGame.GetEntity( nameof(Id), 32 ); // OK
  contextCmd.GetEntity( nameof(Id), 32 ); // Runtime Error or Bug

  // Generic use of PrimaryEntityIndex with Compile time correctness
  contextGame.GetSingleEntBy<Game,Id,Int32>(nameof(Id), 32); // OK
  contextCmd.GetSingleEntBy<Cmd,Id,Int32>(nameof(Id), 32); // Compilation error

  // Extension method for cleaner API
  var ent = contextGame.GetEntityById<Game,Id>( 32 );  // OK
  contextCmd.GetEntityById<Cmd,Id>( 32 );  // Compilation error
}

Authors

• c0ffeeartc