title: what's the counterpart for gl_TexCoord in OpenGL ES 2.0
body: <p>I have a OpenGL shader which uses gl_TexCoord like the following does. But in OpenGL ES, gl_TexCoord is not supported. I wonder what can I do to refactor the code to get it work on OpenGL ES.</p>
  
  <pre><code>void main() 
  {
      //scene depth calculation
      float depth = linearize(texture2D(inputImageTexture2,gl_TexCoord[0].xy).x);
      if (depthblur)
      {
          depth = linearize(bdepth(gl_TexCoord[0].xy));
      }
  
      ...
  }
  </code></pre>