   Bilinear filtering shader artifacts
  Hello,I implemented a very basic bilinear interpolation pixel shader in glsl.It's fine for the most part. Except when I zoom in on my texture, and depending where I am in it, I'm seeing weird lines showing a miscalculation... I read upon it, it appears it's due to a quad misalignment with the screen... My scene is 2D, there's a quad, one texture is applied on it...that's it...I am confused though about what to do, it seems one solution is a half a pixel shift...but is it for texture coordinates? quad coordinates? None of what I tried seems to work...Thanks for any help.   