title: OpenGL flip or mirror the drawing object
body: <p>How can i flip, ot mirror up/left of the image OBJECT, not the screen in the onDraw method?</p>
  
  <p>I tried scale(1, -1, 1) that not worked</p>
  
  <p>my code:</p>
  
  <pre><code> opengl.selectVertex(vertexname)
                                  .translate(x-1, y, -9);
  
                                  if (opengl.getPathModifier(vertexname).getAngle()&gt;-180 &amp;&amp; 
                                      opengl.getPathModifier(vertexname).getAngle()&lt;0 ) {
                                      opengl.selectVertex(vertexname).scale(-scale,scale,1);  
                                  } else {
                                      opengl.selectVertex(vertexname).scale(scale,scale,1);
                                  }
  
  opengl.rotate(opengl.getPathModifier(vertexname).getAngle()+90, 0, 0, 1);
  </code></pre>