Add concealment stat

[Keshash]

Additions

Describe new functionality added by your code, e.g.

• Adds concealment stat for targets that increases visibility penalties against them. 100% by default. Can be increased or reduced, so conspicuous targets can decrease aiming penalties against them. Both stats can be applied to implants, apparel and weapons just like night vision.
• Adds a line to the shooting tooltp about it

References

Links to the associated issues or other related pull requests, e.g.

• Trimmed down version of Thermal vision, concealment and visibility warmup penalties #4067 for easier reviewing experience

Reasoning

Why did you choose to implement things this way, e.g.

• There are multiple mods that try to implement camouflage stats, but CE doesn't support the bonuses it gives.
• Concealment buffs could be used to make certain enemies more elusive, forcing additional aiming errors against them. Could be used to buff silenced weapons. Could use it to make proper ghillie suits. Or it could be used to make certain big armors more undesirable.

Testing

Check tests you have performed:

• Compiles without warnings
• Game runs without errors
• (For compatibility patches) ...with and without patched mod loaded
• Playtested a colony (specify how long)

[github-actions]

You can download the rebuilt assembly for this PR here: https://combatextended.lp-programming.com/CombatExtended-30579794133.zip

[N7Huntsman]

Changes:

• The stat description should be revised to clearly state that the stat is a direct multiplier on range error. The current description notes it "increases" it, but doesn't really explain in what way.
• Do we want to add a separate debug setting to the aiming tooltip to denote the effect from concealment, similar to how we breakout other factors? It's currently captured within visibility shift.

General Remarks:

• How difficult would it be to support a stat property that can be given to a stuffable material? e.g. a futuristic "chameleon cloth" sort of thing that clothing can be made from.
  • I don't know if we'd want this to apply to a longsword made out a "chameleon metal" because it doesn't make a lot of logical sense, but I'm not sure how we'd handle that.

Balance:
I'm not sure exactly how situational we're expecting this to be, but the current effect on range error (as displayed by the aiming tooltip) is negligible.

For testing purposes, I applied <ConcealmentEfficiency_Apparel>10</ConcealmentEfficiency_Apparel> to the Burka. At max range with a Normal quality bolt action rifle during artificial light (~50% brightness) with a Level 1 shooter, the observed Visibility Errors and the associated Range Error were:

• No burka: 7.40 | 31.81
• Awful quality burka: 7.40 | 31.82
• Normal quality burka: 7.40 | 31.82
• Masterwork quality burka: 7.41 | 31.85

Under the same circumstances during mid-day light (100% brightness), the visibility error on all 4 targets was 0, and the range error was identical.

So, somewhere along the line the overall impact of your concealment factor is getting crushed by the other light calculations.

Bugs:

• Pawn has no implants, but implant concealment is 100% (See image below)

---

Burka Example & Test Save

	<Operation Class="PatchOperationAdd">
		<xpath>Defs/ThingDef[defName="Apparel_Burka"]/equippedStatOffsets</xpath>
		<value>
			<ConcealmentEfficiency_Apparel>10</ConcealmentEfficiency_Apparel>
		</value>
	</Operation>

camo test.zip

[Keshash]

The stat description should be revised to clearly state that the stat is a direct multiplier on range error. The current description notes it "increases" it, but doesn't really explain in what way.

Currently doesnt affect range error. see below

How difficult would it be to support a stat property that can be given to a stuffable material? e.g. a futuristic "chameleon cloth" sort of thing that clothing can be made from.

I'll check

So, somewhere along the line the overall impact of your concealment factor is getting crushed by the other light calculations.

This is because it currently only applies to visibility error, which is: light, smoke and weather. Range error is a separate error. However, it makes sense that range error should be affected, I'll add that

Pawn has no implants, but implant concealment is 100% (See image below)

The way it works, is that 1.0 is the default value, so that you could reduce it to between 0 and 1 and make pawn MORE visible than they normally would be (anti-concealment). E.g. if they're wearing a bright glowing red dot on their face.