Multipass vs. Multitexturing

Are there any examples available that show to to emulate multitexturing with multipass rendering? I can think of all sorts of problems I can run up against primarily sorting and z-buffer problems and I’ve never been good with blending modes… which ones properly emulate GL_MODULATE and GL_ADD (in respect to multitexturing)?

just render your second pass with glDepthFunc(GL_EQUAL) also depth writes off.

also, for the first pass you need to set:

glBlendFunc(GL_ONE, GL_ZERO)

And for the other passes:


GL_ADD -> glBlendFunc(GL_ONE, GL_ONE)

Thank you both very, very much!!

Also, modulate x2 is (GL_DST_COLOR, GL_SRC_COLOR)