text: /* $Id: mainOverlayNoDiscard.c 71027 2018-02-15 14:33:48Z vboxsync $ */
  #extension GL_ARB_texture_rectangle : enable
  uniform sampler2DRect uDstTex;
  uniform vec4 uDstClr;
  void vboxCConv();
  void main(void)
  {
      vec4 dstClr = texture2DRect(uDstTex, vec2(gl_TexCoord[1]));
      vec3 difClr = dstClr.rgb - uDstClr.rgb;
      if(any(greaterThan(difClr, vec3(0.01, 0.01, 0.01)))
          || any(lessThan(difClr, vec3(-0.01, -0.01, -0.01))))
      {
          gl_FragColor = dstClr;
      }
      else
      {
          vboxCConv();
      }
  }
  