Quick answer: Pygame fullscreen toggle resetting the mouse to center of screen? OS shifts cursor on resolution change; capture position before toggle and restore.

Player aiming; tap F11 fullscreen; cursor jumps to center; aim disrupted.

Capture and restore

pos = pygame.mouse.get_pos()
pygame.display.toggle_fullscreen()
pygame.mouse.set_pos(pos)

Position preserved across toggle.

Or normalize coordinates

Track mouse position normalized 0-1. Toggle preserves normalized; absolute pixel position computed.

Hide cursor during gameplay

Aim via virtual cursor (drawn sprite); OS cursor is hidden. Toggle doesn't affect virtual.

“Resolution changes affect cursor coordinates. Capture is the cure.”

If your game uses mouse aim, the fullscreen-toggle cursor preservation is mandatory.

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