private function drawFlame():void {
                          // draw the current stage image into flame at a reduced brightness and alpha
                          _flame.draw(
                                  stage,
                                  null,
                                  new ColorTransform(.9, .9, .9, .7)
                          );
                          // blur drawn image slightly, more on y axis
                          ImageUtil.applyFilter(
                                  _flame,
                                  new BlurFilter(3, 5)
                          );
                          // move the flame image up slightly, creating upward movement of flames
                          _flame.scroll(0, -4);
                          // apply new Perlin noise with altered offset
                          applyNoise();
                          // displacement flame image with updates Perlin noise
                          ImageUtil.applyFilter(
                                  _flame,
                                  new DisplacementMapFilter(
                                          _perlinNoise,
                                          new Point(),
                                          BitmapDataChannel.RED,
                                          BitmapDataChannel.RED,
                                          1,
                                          10,
                                          DisplacementMapFilterMode.CLAMP
                                  )
                          );
                  }