_createRenderCmd() {
    if (cc._renderType === cc._RENDER_TYPE_CANVAS) {
      return this._super();
    }
    return new FXProceduralDistortionSprite.WebGLRenderCmd(this);
  }
*************************************************************************
FXProceduralDistortionSprite
var FXProceduralDistortionSprite = FXDistortionSprite
FXProceduralDistortionSprite.create()
- abstract class for creating procedural distortion via shaders.
**************************************************************************