[BTS] First strikes are insane

Seems that @drewisfat is correct.

Yes, I was mistaken that the number of first strikes is fixed.

Count of first strikes is a combination of 2 things:

Code:

     setCombatFirstStrikes((pCombatUnit->immuneToFirstStrikes()) ? 0 : (firstStrikes() + GC.getGameINLINE().getSorenRandNum(chanceFirstStrikes() + 1, "First Strike")));

one fixed and one random in a range from 1 to some N.

I tried to follow logic in code and it was hard to make definite conclusion, so I just bring reasonable explanation without pretending of its 100% correctness.

CIV4UnitInfos.xml:

Code:

<UnitInfo>
  <Class>UNITCLASS_CROSSBOWMAN</Class>
  <Type>UNIT_CHINA_CHOKONU</Type>
  <bFirstStrikeImmune>0</bFirstStrikeImmune>
  <iFirstStrikes>2</iFirstStrikes>
  <iChanceFirstStrikes>0</iChanceFirstStrikes>

<UnitInfo>
  <Class>UNITCLASS_MARINE</Class>
  <Type>UNIT_AMERICAN_NAVY_SEAL</Type>
  <bFirstStrikeImmune>0</bFirstStrikeImmune>
  <iFirstStrikes>1</iFirstStrikes>
  <iChanceFirstStrikes>1</iChanceFirstStrikes>

<UnitInfo>
  <Class>UNITCLASS_CHARIOT</Class>
  <Type>UNIT_EGYPT_WARCHARIOT</Type>
  <bFirstStrikeImmune>1</bFirstStrikeImmune>
  <iFirstStrikes>0</iFirstStrikes>
  <iChanceFirstStrikes>0</iChanceFirstStrikes>

CIV4PromotionInfos.xml:

Code:

<PromotionInfo>
  <Type>PROMOTION_DRILL1</Type>
  <bImmuneToFirstStrikes>0</bImmuneToFirstStrikes>
  <iFirstStrikesChange>0</iFirstStrikesChange>
  <iChanceFirstStrikesChange>1</iChanceFirstStrikesChange>
<PromotionInfo>
  <Type>PROMOTION_DRILL2</Type>
  <bImmuneToFirstStrikes>0</bImmuneToFirstStrikes>
  <iFirstStrikesChange>1</iFirstStrikesChange>
  <iChanceFirstStrikesChange>0</iChanceFirstStrikesChange>
<PromotionInfo>
  <Type>PROMOTION_DRILL3</Type>
  <bImmuneToFirstStrikes>0</bImmuneToFirstStrikes>
  <iFirstStrikesChange>0</iFirstStrikesChange>
  <iChanceFirstStrikesChange>2</iChanceFirstStrikesChange>
<PromotionInfo>
  <Type>PROMOTION_DRILL4</Type>
  <bImmuneToFirstStrikes>0</bImmuneToFirstStrikes>
  <iFirstStrikesChange>2</iFirstStrikesChange>
  <iChanceFirstStrikesChange>0</iChanceFirstStrikesChange>

So there is a fixed component and a variable component. getSorenRandNum(N+1) gives numbers 0, 1, ..., N with probability 1/(N+1).

Drill 1 + 2 + 3 gives:
fixed = 1
variable = 1 + 2 = 3
So distribution is 1 / 2 / 3 /4 (with equal probability of 25%).

Drill 1+2+3+4 gives:
fixed = 1+2 = 3
variable = 1 + 2 = 3
So distribution is 3 / 4 / 5 / 6 (with equal probability of 25%).