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I've been going over this for a couple of days and I'm stumped. This is hopefully a clear update on a question I asked 2 days ago.

I have a ball object with script, collider, rigid body etc. attached. It also has a Plane mesh with a Mesh Renderer attached. The Mesh Renderer has a 2 element array to hold materials. Both are of shader type Particles/Alpha Blended so I don't have to worry about lighting. Element 0 is called m_BallRed. It has a texture map which was originally greyscale but I've set the Tint Color to a red color - that's what I want to change when the game is played. Element 1 is called m_BallHighlight. Element 1 won't change; it's a texture map with an alpha channel which sits on top of the main texture map so I can have highlights that aren't affected by the underlying Tint in Element 0.

When the game is playing I have many different coloured balls in play. I want to change the tint of element 0 of any particular ball to one of several different colors. I figure the best way is to have a series of materials called m_BallRed, m_BallBlue, m_BallYellow etc. When circumstances dictate I want to invoke a ChangeColor() function on the ball which currently contains the following line:

transform.Find("Plane").GetComponent().materials[0] = new Material(Shader.Find("m_BallYellow"));

Once that works I can set about customising the Function, maybe to accept a parameter to specify which color to change the ball to, but I'm getting a NullReferenceException at run time - 'UnityEngine.Material..ctor (UnityEngine.Shader shader)' for that line. So I guess I'm trying to access something that isn't there. Or I'm accessing the chlild Plane's MeshRenderer array of materials wrong. Or... or.... ? Anyone?

Answer 1

0

You could just have an array with the three materials, when wanting to change material you then use this array.

E.g.

MeshRenderer planeRenderer;
Material[] mats; (You could use the inspector to assign the three materials)

Awake()
{
  planeRenderer = GetComponentInChildren<MeshRenderer>();
}

ChangeColour(Color c)
{
  if (c == Color.red)
    planeRenderer.material = mats[0];
  else if (c == Color.blue)
    planeRenderer.material = mats[1];
  else
    planeRenderer.material = mats[2];
}

Try not to use Find all the time, since that can be expensive. Instead cache the things you need.

Oh, and the code is just off the top of my head, so if there are any mistakes in the code. Sorry :)

answered Dec 16 '10 at 02:19 PM

Ejlersen
1.3k ● 1 ● 6 ● 11

Yeah, much better approach to have it cached and look them up in an array.

Dec 16 '10 at 03:00 PM Statement ♦♦

...and that's helped me a lot! I had to tweak my code somewhat to get it to fit but I now have a good base to move forward with. Tak tak!

Dec 16 '10 at 11:46 PM Simon Foster

Whoops! I got my helpers mixed up! Tak tak = thanks a lot!

Dec 16 '10 at 11:47 PM Simon Foster

Vassego! (7 more characters)

Dec 17 '10 at 12:19 AM Statement ♦♦

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Answer 2

But I'm getting a NullReferenceException at run time - 'UnityEngine.Material..ctor (UnityEngine.Shader shader)' for that line. So I guess I'm trying to access something that isn't there.

Yeah, your Shader.Find didn't find anything. (It return null if nothing was found).

So your question is basically condensed to:

Why doesn't Shader.Find("m_BallYellow") return my expected shader?

Your material is called m_BallYellow. With your code, you are trying to find the shader that is called m_BallYellow. But there is no such shader, only such material!

So my answer?

You probably want to find the "Particles/Alpha Blended" shader, and set properties on that.

Material newMaterial = new Material(Shader.Find("Particles/Alpha Blended"));

Community

Changing the material in an array of materials at run time

So my answer?

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