Forward grip for KSG and other shotguns with pump-rail

[Night-Pryanik]

Hopefully this PR solves issues mentioned by @kevingranade in #22150.

[kevingranade]

Special casing it for the ksg isn't an option.
A new slot type would work, like "grip-only-rail".

[Night-Pryanik]

How about adding new flag to KSG and the same guns like PUMP_ACTION_RAIL and special-case flag instead of a gun in question? Or new slot type is better?

[kevingranade]

A new slot type is cleaner code wise, but requires things like rail mounted flashlights to be adjusted as well.

[Night-Pryanik]

We don't have rail-mounted flashlights, or did you mean rail-mounted laser sight?

[Wishbringer]

Both laser and flashlight mods generally use the same type of rail, which is why they often come in combos to save rail slots.

[Night-Pryanik]

New slot type requires creating duplicates of forward grip and laser sight (and maybe some other compatible mods) that have the same characteristics as the originals, but can be mounted only on this new slot, right? At the moment a mod can't be installed on several slots, right? Also, it seems that now we could install, say, aux flamethrower, on other pump-action shotguns like Mossberg 500.

I feel that variant with adding new flag to pump-action shotguns and special-casing it would work better.

[mlangsdorf]

special casing this to only support grips seems very weird to me. You can mount a rail laser spot on a KSG's pump rail.

Wouldn't it make more sense to flag mods that can be mounted on the pump rail with a new flag in the JSON, and then check against that flag instead of grip? Something like

+    } else if( has_flag( "PUMP_ACTION" ) && mod.type->gunmod->location.str() == "underbarrel" && !mod.has_flag( "PUMP_ACTION" ) ) {
+        return ret_val<bool>::make_failure( _("can only accept small mods on that slot") );

grips and rail laser sights would get the PUMP_ACTION flag, but underbarrel crossbows and grenade launchers wouldn't.

[Night-Pryanik]

You can mount a rail laser spot on a KSG's pump rail.

You can, yes (and many other underbarrel mods too), but wouldn't it stand in a way of pumping its action?

[mlangsdorf]

No, the forearm grip rail is about 6" long, so a 2" laser spot still leaves you about 4" of space to hold the pump. See http://blog.cheaperthandirt.com/wp-content/uploads/2011/11/KSG_ammo_4401web.jpg

[Night-Pryanik]

Ok, now only mods with PUMP_RAIL_COMPATIBLE, such as forward grip and laser sight, flag can be installed on underbarrel slot of guns with rails on their pump action.