After few tests, here what I've found :
In
easy mode, the rank is divided in 6
Rank 0 - from 0 points
Rank 1 - from 1834 points
Rank 2 - from 3668 points
Rank 3 - from 5502 points
Rank 4 - from 7336 points
Rank 5 - from 9170 points
In
normal mode, the rank is divided in 10
Rank 1 - from 1000 points
Rank 2 - from 2000 points
...etc
Rank 10 - from 10000 points
For now, my "damage equation" works.
The gun has a firepower set to "1". It means 300 points.
If you upgrade your gun to level "1.4", it means its firepower increases to 300x1.4 = 420
The rank will affect this firepower like this :
Rank 1 : Damage = firepower*0.9 (-10%)
Rank 2 : Damage = firepower*0.8 (-20%)
Rank 3 : Damage = firepower*0.7 (-30%)
Rank 4 : Damage = firepower*0.6 (-40%)
Rank 5 : Damage = firepower*0.5 (-50%)
Rank 6 : Damage = firepower*0.485 (-51.5%)
Rank 7 : Damage = firepower*0.47 (-53%)
Rank 8 : Damage = firepower*0.455 (-54.5%)
Rank 9 : Damage = firepower*0.44 (-56%)
Rank 10 : Damage = firepower*0.425 (-57.5%)
For example. When I RAM watch health ennemies, it works :
- Gun level 1.4 gives 420. At rank 5, the damage is 420*0.5 = 210
- Shotgun level 5 gives 1500 (short distance). At rank 10, the damage is 1500*0.425 = 637.5
Only problem is the TMP. The level 0.4 TMP would have a 300x0.4 (120) firepower. But no ! It's 168. I don't know why. But if you have a level 0.6 TMP, you could find the damage :
0.4 to 0.6 = 1.5 higher
168 * 1.5 = 252
So, I think only the "base" value is different with the TMP. FYI, headshot means a firepower increased by 20%.
I'm only at chapter 2-1. And I have found now a new variable : resistance. So...
damage = base-firepower * weapon-upgrade * rank * headshot / resistance
First ennemis have no resistance (=1). Plagas have 1.5 resistance... but only 0.5 if you shoot their ugly faces.
I don't know if it's interesting for you guys, but it's really fun to do this.
ps : when damage values are rounded, they may not be the same between the PC version, and the GC EUR version. For example, if the gun damage is 270 with GC version, it's "only" 269 on PC version. Also, I'm still studying the game, so maybe I made some mistakes.