I'm running mameuifx32 0.128
with these options:
lightgun 1
This should do it. However, other settings can make a difference.
Do you have -
multimouse also enabled? It's needed if you want two lightguns or two trackballs or one lightgun + one trackball at the same time, but it's harder to set up when enabled even with only one lightgun.
Did you try remapping in mame? (start game, tab, input (this game)) Usually mame's defaults fine, unless -
multiplemouse is enabled, or you remapped previously
sometimes even if the remap was on other inputs for this game. If there was nothing special remapped, try deleting the file term2.cfg in the
cfg mame folder.
Do you have -
mouse enabled? Some guns/OS combos work better with
mouse disabled, others with
mouse enabled. Try and see if it makes a difference for your setup if nothing else works.
mouse_device lightgun
Doesn't do anything in mame, as this is a MESS specific option. (No arcade game used mice.) Think for
xyz_device abc: arcade used xyz for inputs, so mame calls it xyz_device, and for this type of input device, I want to use my PC abc input. BTW, what you have doesn't hurt either, but thought you should know.
If you had lightgun 0, mouse 0, then you'd want
adstick_device lightgun (but see second question above, about mouse enabled/disabled), since term2 uses an absolute analog mounted gun, much like an analog joystick. Mame calls this type of input device "AD Stick" in the input remap menu, thus the adstick_device name.