title: Converting screen coordinates to world coordinates
body: <p>I'm getting screen coordinates using this:</p>
  
  <pre><code>@Override
  public boolean onTouchEvent(MotionEvent ev) {
  x = ev.getX(0);
  y = ev.getY(0);
  return true;
  }
  </code></pre>
  
  <p>And these are the verticles of my openGL 1.0 square:</p>
  
  <pre><code>private float vertices[] = {
          -1.0f, -1.0f,  0.0f,        // V1 - bottom left
          -1.0f,  1.0f,  0.0f,        // V2 - top left
           1.0f, -1.0f,  0.0f,        // V3 - bottom right
           1.0f,  1.0f,  0.0f         // V4 - top right
  };
  </code></pre>
  
  <p>Everybody who have worked with openGL knows, that if i would paste x and y variables instead of verticles, i would get absolute nonsense. My question is: what formula should i use to convert screen coordinates x and y to world coordinates so i could use them to position my square to the touched point?</p>
  
  <p>EDIT:</p>
  
  <p>Oops, i forgot to say, that it's a 2D game...</p>