   Shader Model 3.0 VPOS Semantic
  Hi all, I'm using the VPOS semantic to do some postprocessing on the final rendered image. I'm totally new to shaders and Direct3d stuff. I noticed that VPOS semantic is only supported in ps_3_0 and I was wondering whether I can achieve same functionality with ps_2_0 or not. I need to know exact coordinates of the pixel on the viewport. I'm doing some stereoscopic image stuff and I need to be able to determine whether the currently rendered pixel resides on an odd or even scanline. Any suggestion is well appreciated. I want to be compatible with older hardware if possible that's why I don't want to stick to ps_3_0.Thanks in advance !Fatih   
  Are you just doing full-screen passes?  Usually with this stuff, your quad that you render will just have texture coordinates going from 0-1.  If you take this texture coordinate and multiply it by the dimensions of your render target, you can figure out which pixel you're rendering to.   