Help with GetComponentsInChildren

Unity Engine
1

I’m a bit stumped. If I call GetComponentInChildren, I get an object, but if I call GetComponent__s__InChildren I get nothing, not even the one that is there.

void Start()
{
  Renderer[] rend = GetComponentsInChildren(typeof(Renderer), true) as Renderer[];
  if( rend == null )
  {
    Debug.Log("Failed to find a renderer in " + gameObject.name );

    // I don't believe you
    Renderer rend2 = GetComponentInChildren(typeof(Renderer)) as Renderer;
    if( rend2 != null )
      Debug.Log("Liar. I found one. ");
  }
}

Liar prints for every object. Wha?!

2

I still have no idea why that doesn’t work, and would still love to hear if anyone knows.

The only way I could get it to work was to “manually” go through the children recursively and use their renderer member variable.

In case anyone cares:

void Start() 
{
  List<Renderer> rc = GetRenderersInChildren( transform );
  Renderer[] rend = rc.ToArray();
}

private List<Renderer> GetRenderersInChildren( Transform t )
{
  List<Renderer> renderers = new List<Renderer>();
  if( t.renderer != null )
    renderers.Add( t.renderer );
  foreach( Transform child in t )
    renderers.AddRange( GetRenderersInChildren( child ) );
  return renderers;
}
3

check:

(GetComponentsInChildren(typeof(Renderer), true)).Length

and tell us what u get.

4

If I recall correctly, it was returning values, but they could not be cast to Renderer.

5

u answered ur self :slight_smile:

I think it is because you r casting Component[ ] to Renderer[ ]

instead get the Component[ ] returned by GetComponentsInChildren, iterate through it and cast each element (u know is a renderer) to Renderer.

6

Why are we passing (typeof(Renderer)) if it is not returning Renderers? When you call the singular version, it works as expected:

Renderer rend = GetComponentInChildren(typeof(Renderer)) as Renderer;

works, but on the same object:

Renderer rends[] = GetComponentsInChildren(typeof(Renderer)) as Renderer[];

returns null. Maybe it is not an issue with Unity, but a C# array thing?

7

I believe built in arrays are not reference types, and therefore the ‘as’ keyword wouldn’t work.

You might be able to make the cast using a C-Style cast, however.

8 
Component[] rendererComponents = GetComponentsInChildren(typeof(Renderer)) ;

List<Renderer> answer = new List<Renderer>();

for(int i = 0; i < rendererComponents.Length; i++)
{
    answer.Add((Renderer)rendererComponents[i]);
}

this is it more or less, didn’t compile it just typed it here :slight_smile:

9

Thanks, I believe that will work. Hopefully this will save some people some time in the future.