title: Android OpenGLES set glOrthof to screen coordinates
body: <p>I read that OpenGL have origin in bottom-left corner, but the screen for touch have the origin in top-left corner.</p>
  <p>So, can I set</p>
  <pre><code>gl.glOrthof(0.0f, this.width, this.height, 0.0f, 1.0f, -1.0f);
  </code></pre>
  <p>to match OpenGL to screen coordinates?
  Will I have difficulties with this way?</p>