Access EntityManager from MonoBehaviour (Entities 0.2.0)

Unity Engine
,
1

Hi,

After upgrading to Entities 0.2.0, I can’t get things running anymore. I use procedural generation in MonoBehaviour, which accesses the EntityManager, creating entities at the start of runtime. At some stage I’ll be updating the MonoBehaviour procedural code to a system, but still want to move forward with this setup for now.

Previously I was accessing the EntityManager with World.Active.EntityManager. When replacing this with World.DefaultGameObjectInjectionWorld.EntityManager, I get a message saying that no World is created yet. Looking at the script execution order, I see that the DefaultWorldInitializationProxy runs after all other scripts (and reverts to that position when trying to move it). When I try and run DefaultWorldInitialization.Initialize(“Default World”, false) to create a world prior to running the MonoBehaviours, it freezes.

Any advice much appreciated, thanks!

2

So from now on, you are responsible for initializing a default world and setting up World.DefaultGameObjectInjectionWorld in your CustomBootstrap.

For example, from the release log:

class MyCustomBootStrap : ICustomBootstrap
{
  public bool Initialize(string defaultWorldName)
  {
      Debug.Log("Executing bootstrap");
      var world = new World("Custom world");
      World.DefaultGameObjectInjectionWorld = world;
      var systems = DefaultWorldInitialization.GetAllSystems(WorldSystemFilterFlags.Default);

      DefaultWorldInitialization.AddSystemsToRootLevelSystemGroups(world, systems);
      ScriptBehaviourUpdateOrder.UpdatePlayerLoop(world);
      return true;
  }
}
1 Like
3

Thanks @Singtaa ! Still can’t get things running, but the debugger doesn’t even reach this, so it must be something else that happened during the upgrade. Will keep looking.

4

Have you tried deleting the Library folder to force Unity to recompile everything from scratch?

5

Yes had tried that, but it’s still hanging. I might try re-installing the latest packages.

6

Where are you calling World.DefaultGameObjectInjectionWorld.EntityManager from in your monobehaviour.

7

I call it in the Start function, then that entityManager variable is used later on in the script. Now I can’t even launch the project in the editor, it crashes during the Unity splash screen. Will uninstall and start again…

8

Tried reinstalling packages, deleting library folder and different Unity versions but couldn’t get 0.2.0 working. Now just upgraded to 0.3.0 and it’s all working again finally :slight_smile: