LaunchScreen storyboard tutorial

I faced with a black screen flashing between the launchscreen and the clear_color of the render script. What could be wrong?

Render script:

function init(self)
  ...
  self.background_color = vmath.vector4()
  self.background_color.x = sys.get_config('render.clear_color_red', 0)
  self.background_color.y = sys.get_config('render.clear_color_green', 0)
  self.background_color.z = sys.get_config('render.clear_color_blue', 0)
  self.background_color.w = sys.get_config('render.clear_color_alpha', 0)
  ...
end

function update(self)
  render.set_depth_mask(true)
  render.set_stencil_mask(0xff)
  render.clear({
    [render.BUFFER_COLOR_BIT] = self.background_color,
    [render.BUFFER_DEPTH_BIT] = 1,
    [render.BUFFER_STENCIL_BIT] = 0
  })
  ...
end

Game project:

...
[render]
clear_color_red = 0.973
clear_color_green = 0.969
clear_color_blue = 0.953
clear_color_alpha = 1.0
...

Storyboard:
LaunchScreen.zip (3.8 KB)