feat(balance): make AoE damage falloff based on range

[scarf005]

Purpose of change (The Why)

• resolves Damage falloff with distance for AoE ammo #6028

Describe the solution (The How)

see: #6028 (comment)

falloff is limited to at most 50% of damage

Describe alternatives you've considered

• add UI for it but the formula is simple enough so we could add them later.
• could also make falloff begin at half the max range but then it'd need UI to communicate the falloff so it's not in scope of the PR.

Testing

2025-02-02_12-17-54.mp4

1. spawn zombies
2. fire saiga
3. see that far away zombies take less damage

Checklist

Mandatory

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax like closes #1234 in Summary of the PR so it can be closed automatically.
• I've committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.

[chaosvolt]

1. Compiled and load-tested.
2. Spawned in a shotgun and loaded it with birdshot.
3. Spawned in a gaggle of zombies to test it against.
4. Observed the damage numbers seem to vary with distance.

That said uh, AoE can crit it turns out, completely at random and separately for every single zed hit by it, which makes it REALLY hard to actually tell if this is scaling right or not. XD

Point-blank:

Guy behind them is also dead:

Next person in line is unexpectedly actually less injured instead of more:

Fourth in line took slightly MORE damage than third place?

Last guy at the end actually looks like damage falloff has happened:

[scarf005]

the damage log should show how much damage has been dealt with like my screenshot shows

[chaosvolt]

Gave myself the "no ranged crit" mutation and tested again to grab the damage log:

Main problem with using this for testing is I dunno what order it's going in. Your test showed higher numbers up top to imply it's going from closest to furthest, while mine seems to be in ascending order as if it's standing with the ones at the end instead? This is confusing...

That said, without random crits messing things up I can see a more overt progression as I hover on down the line from closest to farther, going from 29 HP left to 50 HP left at the end.

[chaosvolt]

So given that, that seems to confirm it works. Will go ahead and wait for others to look at it too, mainly because I dunno if they'd want to suggest a different rate of damage falloff of whether they're fine with the current "half damage at max range" scaling.

[scarf005]

went to 50% scaling because it's simple, just as Coolthulhu intended

[chaosvolt]

went to 50% scaling because it's simple, just as Coolthulhu intended

Only issue is the phrasing implies more aggressive scaling than "half at max range", hecc. Decided to pester him on the server and wait for a reply to clarify if that's what he meant or not before making any code suggestions tho:

[chaosvolt]

In the event that Coolthulhu does say to scale it all the way down instead of half damage being the minimum damage, the below is the change that'd be needed to implement it. Can just leave it here while we wait to find out whether it's needed or not, and mark as resolved if we end up not using it.

With buckshot (10 range) previous tests showed this increased level scaling will produce 60% damage when target is 5 tiles away and 10% damage when target is the full 10 tiles away.

[chaosvolt]

Suggested change

	return 1 - ( 0.5 * ( std::max( 0.0f, dist - 1 ) / range ) );
	return 1 - ( 1 * ( std::max( 0.0f, dist - 1 ) / range ) );