Create An Dynamic Buffer list and Set Spawner Component Data and Instantiate

Unity Engine
, ,
1

Hello,
I’m going to make a game similar to tower defense. ECS seemed very suitable especially for war systems and I left OOP and turned to ECS.
Now I create a subscene and collect my building types there.
Just like in this video

i convert GameObject to Entity and load to dynamic buffer.

public class PrefabListAuthoring : MonoBehaviour, IDeclareReferencedPrefabs, IConvertGameObjectToEntity
{
    public GameObject[] prefabs;
    public void DeclareReferencedPrefabs(List<GameObject> referencedPrefabs)
    {
        foreach (var prefab in prefabs)
        {
            referencedPrefabs.Add(prefab);
        }
    }

    public void Convert(Entity entity, EntityManager dstManager, GameObjectConversionSystem conversionSystem)
    {
        var buffer = dstManager.AddBuffer<SpawnerListComponent>(entity);

        foreach (var prefab in prefabs)
        {
            buffer.Add(new SpawnerListComponent { prefab = conversionSystem.GetPrimaryEntity(prefab) });
        }
    }

Buildings are loading into dynamic buffer and now I just want to change the spawnerComponent Value when I press a number and display a new object on the screen with Spawner. But I couldn’t even select the object yet. Can you help me?

PS By the way, this is not my ultimate goal of course. With Raycast, I will instatiate building where the mouse clicks.

Dynamic Buffer :

public struct SpawnerListComponent : IBufferElementData
{
    public Entity prefab;
}

Component Data:

public struct SpawnerComponent : IComponentData
{
    public Entity prefab;
}

Dynamic Buffer to Component Data load or selection system:

public partial class SpawnerControlSys : SystemBase
{

    protected override void OnUpdate()
    {
        var e = GetSingleton<SpawnerComponent>().prefab;
        var buffer = EntityManager.GetBuffer<SpawnerListComponent>(e);

        if (Input.GetKeyDown(KeyCode.Alpha1))
        {
            Debug.Log("You pressed to Alpha1");
            EntityManager.SetComponentData(e, new SpawnerComponent { prefab = buffer[0].prefab });
        }
2

What do you mean by this?

3

The gameobject with SpawnerComponent prefab value is not changing. It only say none. I am trying to change that data and then create a system so I can spawn that prefab.

4

I still don’t think I understand what you are asking. But I’m going to take some stabs in the dark. Is your DynamicBuffer fully populated with non-Null entities?

5

Let me explain from top to bottom.
My main goal is to load different buildings into a dynamic buffer and then extract data from it and instantiate building with one spawner.
My approach is

  1. Converting Gameobject(Building) list to entity. MonoBehaviour, IDeclareReferencedPrefabs, IConvertGameObjectToEntity.
  2. Then load this GameObject(Building) list into a dynamic buffer. This part of script has already worked and when i look at the Debugger screen, GameObject(Building) list loaded to dynamic buffers and appeared.
  3. Then trying to load one building entity from the GameObject(Building) list that I have loaded into this buffer into spawner’s component data. (In this example, I tried to do it by pressing a number. But I will use the UI in the future.) I am trying to do this with a system. It didn’t work as I expected.
  4. Afterwards, constructing buildings on the screen with this spawner.

The missing part is to load any object from the GameObject (Building) list into the spawner component data(It is single object and I thought it can be a singleton) . When I press 1, Debug.Log appears, but the spawner component data prefab value does not change.

Maybe i’m thinking like an OOP guy because i did it like that: There is a Building List ( Scriptable object) (and then)=> a spawner object (and then)=> load to one of spawing building to this spawner object with UI (and then)=> click to screen (and then)=> instantiate building in the map.

I know you can do this task with blob asset but i don’t understand very well it and i am self-taught guy who is background 3d. It is hard and it is not like scriptable object. I find a blog which it tells scriptable object to blob asset.
If i can achieve that i won’t need this solution.

PS: Thank you.

6

Oh. I think I see your issue now. You are trying to set a new SpawnerPrefab component on the prefab currently held by the existing SpawnerPrefab singleton. Instead of GetSingleton().prefab, I think you want to use GetSingletonEntity(). I’m kinda surprised you didn’t get an error though.

7 
        var e = GetSingletonEntity<SpawnerComponent>();
        var bufferEntity = GetSingletonEntity<SpawnerListComponent>();
        var buffer = GetBuffer<SpawnerListComponent>(bufferEntity);

        if (Input.GetKeyDown(KeyCode.Alpha1))
        {
            Debug.Log("You pressed to Alpha1");
            EntityManager.SetComponentData(e, new SpawnerComponent { prefab = buffer[0].prefab });
        }

I changed the SpawnerControlSys code like that and work like a charm.
Thank you very much.