Headless window using a standalone moderngl.Context.



Creates a standalone moderngl.Context. The headless window currently have no event input from keyboard or mouse.

Using this window require either settings values to be present:

  • HEADLESS_FRAMES: How many frames should be rendered before closing the window
  • HEADLESS_DURATION: How many seconds rendering should last before the window closes
Window.draw(current_time, frame_time)

Calls the superclass draw() methods and checks HEADLESS_FRAMES/HEADLESS_DURATION


Binds the framebuffer representing this window

Window.should_close() → bool

Checks if the internal close state is set


Sets the internal close state

Window.resize(width, height)

Resizing is not supported by the headless window. We simply override with an empty method.


Headless window currently don’t support double buffering. We only increment the frame counter here.


No teardown is needed. We override with an empty method

Other Inherited Methods


Calculates the viewport based on the configured aspect ratio in settings. Will add black borders if the window do not match the viewport.

Window.cursor_event(x, y, dx, dy)

The standard mouse movement event method. Can be overriden to add new functionality. By default this feeds the system camera with new values.

  • x – The current mouse x position
  • y – The current mouse y position
  • dx – Delta x postion (x position difference from the previous event)
  • dy – Delta y postion (y position difference from the previous event)
Window.keyboard_event(key, action, modifier)

Handles the standard keyboard events such as camera movements, taking a screenshot, closing the window etc.

Can be overriden add new keyboard events. Ensure this method is also called if you want to keep the standard features.

  • key – The key that was pressed or released
  • action – The key action. Can be ACTION_PRESS or ACTION_RELEASE
  • modifier – Modifiers such as holding shift or ctrl

Clear the window buffer

Window.clear_values(red=0.0, green=0.0, blue=0.0, alpha=0.0, depth=1.0)

Sets the clear values for the window buffer.

  • red (float) – red compoent
  • green (float) – green compoent
  • blue (float) – blue compoent
  • alpha (float) – alpha compoent
  • depth (float) – depth value

Prints moderngl context info.



(width, height) tuple containing the window size.

Note that for certain displays we rely on buffer_size() to get the actual window buffer size. This is fairly common for retina and 4k displays where the UI scale is > 1.0


(width, heigh) buffer size of the window.

This is the actual buffer size of the window taking UI scale into account. A 1920 x 1080 window running in an environment with UI scale 2.0 would have a 3840 x 2160 window buffer.

Window.keys = None