   blending a textured quad
  Hi guys ... i am rendering 2d and 3d at the same time .. that is one after the other .. now what i want to do is draw a quad in 2d that will be tarnsparent and the background 3d objects can be seen .. actually this part i managed to do . but when i get a texture on that quad how do i blend now .. i am coding in openGl please answer in that contextthankz for yur help in advance  