#1377 Implement Laser-Guided Bomb Munition

[visplane overflow]

Laser guided bombs are selectable as external ordnance for Aeros and Conv Fighters, and can be dropped normally but do not get the -2 to hit modifier against targets that have been "painted" by friendly TAG. Additionally, you don't get an "Indirect fire" phase when a unit is carrying Laser Guided Bombs either.

The rules citation is from Total Warfare, page 246 :

"Laser-Guided (LG): Laser-guided bombs act exactly like HE
bombs, except when targeted against a unit designated by a
friendly TAG (see below). Against such units, apply a –2 to-hit
modifier."

[Derrick Turk]

Ok, I've taken a crack at this as a patch (attached). Some things to note:

You'll get an indirect phase for your TAG units as long as you have any units with any undropped LG bombs.

Bomb types are selected after "firing", so the modifier doesn't appear in the UnitDisplay; it's applied (and shown) during the to-hit roll resolution. I've added the notion of a "bomb type-modified to hit" to handle any similar cases in the future.

Bombs target hexes, not units, so you'll need to TAG the relevant hex. The only case I can think of where being able to target the hex of a tagged unit (instead of hex) would matter is when your tagging unit has LOS to a unit but not to its hex due to intervening terrain. If this is a legitimate case, we can add a check for tagged units in target hex. It wasn't clear to me from the rules whether this should happen or not.

[Nicholas Walczak]

I'm fairly certain that the you must have LoS to the hex and tag the hex for laser-guided bombs. If you can see the unit, but not the ground, you can't make the attack. There are situations like this for other weapons (copperhead rounds and homing Arrow IV come to mind), and I'm pretty sure they work this way.

It may seem kind of weird and arbitrary, but those are the rules as I understand them. My impression is that the number of times this comes up in practice is vanishingly small. Just means you need to put your TAG on a VTOL, hehe.

[Klaus Mittag]

Actually, as it stands MegaMek still insists that to make homing artillery attacks you need to first of all have tagged a unit. Homing shots at tagged non-unit targets like hexes and buildings should by rights be legit, but aren't implemented yet last time I checked (and for that matter, the set/getTaggedBy methods are currently Entity-only in the source when they should arguably be conceptually part of the Targetable interface -- pretty much anything that can be targeted, save infantry, can also be tagged after all).

[Derrick Turk]

And, of course, I forgot to include the added report message for LGBs in the previous patch. Sorry!

Updated patch attached.

[Hammer]

Committed revision [r11884]

[Derrick Turk]

It looks like the ammo check in Server got doubled up in r11884. It doesn't break anything, but we can remove the second duplicate loop:

        for (Mounted b : entity.getBombs()) {
            if (!b.isDestroyed()
                && (b.getUsableShotsLeft() > 0)
                && (((BombType) b.getType()).getBombType() == BombType.B_LG)) {
                return true;
            }
        }

[Hammer]

Thanks, I'll get it fixed. Must of patched funny on my end.