mulitexture crossfading

I’ve been searching these boards over and over and have mostly just gotten confused.

I have two textures, and I want to use multitexturing to blend say, 20% of one texture on a polygon and then blend 80% of the other texture.

Can anyone help me out here?

Thanks very much

GL_ARB_texture_env_combine

Use this one (from the spec):

INTERPOLATE_ARB Arg0 * (Arg2) + Arg1 * (1-Arg2)

Ok, color me stupid … I am green with respect to interpreting these extension specs and translating them to source code. Where can I get a good tutorial on interpreting these documents? Any help would be appreciated.