How to change material ?

Scripting Issues
1

I have a car model which has only one material defined for the body part.

<Material> "Car paint 3" {
  <Scalar> diffr {0.0}
  <Scalar> diffg {0.7}
  <Scalar> diffb {0.0}
  <Scalar> specr {0.742455124855}
  <Scalar> specg {0.742455124855}
  <Scalar> specb {0.742455124855}
  <Scalar> shininess {127.75}
}

I change the car of the body by:

        self.npBody = self.carbody_view.find("**/body")
        material = self.npBody.findMaterial("*")
        material.setDiffuse(color)
        self.npBody.setMaterial(material)

But the color of the car become the new color blended with the original material color. How can I correct this ?

2

When you are using the auto-shader, you are not allowed to directly modify Material objects (because the auto-shader can’t detect this). Instead, create a new Material object:

material = Material(material)
material.setDiffuse(color)

And use an override when you reapply it, in case you’re not applying it to the actual node that contained the original material object:

self.npBody.setMaterial(material, 1)

David

3

Really? glGSG::set_state_and_transform asks the shader context to re-issue the material parameters when the MaterialAttrib has changed, right?

4

Yes, but directly changing the parameters of the Material will not change the MaterialAttrib that references it. The only way to change the MaterialAttrib is to create a new Material object.

David

5

I did not use auto shader in this case.

I have tried your suggestion, the result is the same. Any idea? Or I need to upload the model for a further check ?

Thank you.

6

Ok, I find the answer. By default the material ambient color seems follows the diffuse color. I add also material.setAmbient(color) the blending issue is gone.