I want to render billboards that are using GL_NEAREST texture mode while GL_BLEND and GL_ALPHA_TEST are enabled. To disable the problem with the pixels at the side of the billboard (the alpha channel is also smoothed) i'm using multitexturing with the alpha channel of a GL_NEAREST texture and the color channel of a GL_LINEAR texture.
The problem is that if I use the same texture for both texture units the GL_(LINEAR/NEAREST) is a texture parameter instead of an unit parameter and both of my textures are LINEAR. Is there a way to duplatate the texture (and thus I would be able tho set LINEAR/NEAREST independently)while pointing to the same data in texture memory?
ps: If there is an earsier way to fix the billboard problem I would like to hear it.