Help required with setting up my mouse as a lightgun within the opera-libretro (3DO) core of Retroarch

[St_Eddie]

Hi,

I'm struggling with attempting to use my mouse as a lightgun for the 3DO core of Retroarch.  The game I'm trying to achieve this with is StarBlade.  I've tried all sorts of combinations within Retroarch's port 1 and 2 control settings; for example, port 1 as a joypad and port 2 as a 3DO lightgun, or port 1 as the Arcade lightgun and port 2 as nothing.

However, the the main issue is that I'm able to achieve moving the on screen cursor with my mouse when setting port 1 as either the 3DO or Arcade lightgun (as well as having an on screen UI overlay cursor) but unable to use any of the mouse buttons.  Whereas, if I set port 2 as the lightgun, then I am able to use the mouse buttons in-game (including to shoot), but unable to alter my aim with the mouse (even the on screen UI cursor disappears)!  It's rather maddening.  I even tried to set both ports 1 and 2 as lightguns in the hope that it may create some kind of Frankenstienian monster, but sadly nothing seems to work.  I can only either shoot or move the reticle, but not both.

Any help would be greatly appreciated.  Thank you.