title: Three.js custom shader error on Chrome GL_INVALID_OPERATION: Active draw buffers with missing fragment shader outputs
body: <p>I want to build a custom shader which will not be rendered. I mean I want to tell fragment shader not to write anything. So, on fragment shader I am not setting gl_FragColor.</p>
  
  <p>The program works well on Firefox and Edge but not working on Chrome. On Chrome has warning: "GL_INVALID_OPERATION: Active draw buffers with missing fragment shader outputs."</p>
  
  <p>Can you help me to solve this problem on Chrome? Is there any settings to accept shader without fragment?</p>
  
  <p>vertexShader:</p>
  
  <pre><code>  void main() 
    {
      vec4 modelViewPosition = modelViewMatrix * vec4(position, 1.0);
      gl_Position = projectionMatrix * modelViewPosition;
    }
  </code></pre>
  
  <p>fragmentShader:</p>
  
  <pre><code>  void main() {
      return;
    }
  </code></pre>