opengl and mtl parameters

Question

Hi,

I am new to opengl.

I am trying to parse line items from "mtl" file and use the values as parameters to opengl functions.

I could use values of ambience (Ka), specular(Ks) and diffuse(Kd) using glMaterialfv. But I don't know the use for Ni (optical density), d (dissolve), illum (illumination) values given in the mtl file.

Which opengl function should be used with these values?

Any help with these line items is appreciated.

....

....

Ni 1.000000

d 1.000000

illum 2

...

...

Thanks in advance.

John

Answer 1

Dissolve means transparency. 1.0 means fully opaque object, 0.0 means fully transparent. You can control rendering of transparent objects by using functions like glBlendFunc().