title: OpenGLES 2.0 fragment shader alpha fail?
body: <p>I would expect my texture to disappear completely with the following fragment shader:</p>
  
  <pre><code>varying mediump vec2 text_coord_out;
  uniform sampler2D sampler;
  
  void main()
  {
      gl_FragColor = texture2D(sampler, text_coord_out);
      gl_FragColor.w *= 0.0;
  }
  </code></pre>
  
  <p>. . .it doesn't.  I've also tried gl_FragColor.a.  Thoughts?</p>