Mob::CheckDoubleAttack problems

[Kayen]

bool Client::CheckDoubleAttack(bool tripleAttack) {

	// If you don't have the double attack skill, return
	if(!HasSkill(DOUBLE_ATTACK) && !(GetClass() == BARD || GetClass() == BEASTLORD))
		return false;

	// You start with no chance of double attacking
	int chance = 0;

	// Used for maxSkill and triple attack calcs
	int8 classtype = GetClass();

	// The current skill level
	uint16 skill = GetSkill(DOUBLE_ATTACK);

	// Discipline bonuses give you 100% chance to double attack
	sint16 buffs = spellbonuses.DoubleAttackChance + itembonuses.DoubleAttackChance;

	// The maximum value for the Class based on the server rule of MaxLevel
	int16 maxSkill = MaxSkill(DOUBLE_ATTACK, classtype, RuleI(Character, MaxLevel));

	// AA bonuses for the melee classes
	int32 aaBonus =
		GetAA(aaBestialFrenzy) +
		GetAA(aaHarmoniousAttack) +
		GetAA(aaKnightsAdvantage)*10 +
		GetAA(aaFerocity)*10;

	// Bard Dance of Blades Double Attack bonus is not cumulative
	if(GetAA(aaDanceofBlades)) {
		aaBonus += 500;
	}

	// Half of Double Attack Skill used to check chance for Triple Attack
	if(tripleAttack) {
		// Only some Double Attack classes get Triple Attack
		if((classtype == MONK) || (classtype == WARRIOR) || (classtype == RANGER) || (classtype == BERSERKER)) {
			// We only get half the skill, but should get all the bonuses
			chance = (skill/2) + buffs + aaBonus;
		}
		else {
			return false;
		}
	}
	else {
		// This is the actual Double Attack chance
		chance = skill + buffs + aaBonus;
	}

	// If your chance is greater than the RNG you are successful! Always have a 5% chance to fail at max skills+bonuses.
	if(chance > MakeRandomInt(0, (maxSkill + itembonuses.DoubleAttackChance + aaBonus)*1.05)) {
		return true;
	}

	return false;
}

While trying to properly implement the AA's for double attack, I came to conclusion the entire function is rather flawed but being such a vital part of the attack code, I don't want to change anything without bring it up for review in the event that I am really tired and missing something.

Essentially its written as you have at any skill level a 95% chance to double attack as long as your skill = maxskill for that level.

Ie at level 15, maxskill is 85, so if your 85/85 you hit 95%, therefore making the actual skill level irrelevant.

Beast/Bard skill level on live is capped at 25. However if we use our formula as long as your 25/25 your at 95%. Flawed.

Further more, this makes all AA and Worn Effects (ferocity) 100% null because they are canceled out in the calculation.

Finally it assumes any spell bonuses = 100% chance which is just totally incorrect because the ranges of spell values for double attack in the dbase range from 4% to 10000% ect.

The bottom line calculation is.

Skill + itembonus + AAbonus + spellbonus >
Rand(0,MaxSkill + itembonus + AAbonus *1.05)

As you can see item bonuses and AA bonuses are in all cases negated from both sides of the equation. Assuming you have no spellbonuses you are left with your 95% chance.

After doing some searching I found that live uses a formula:
(skill*skillmod) + level * (100 + totalfocus/100) / 500;

Unless there is some objection I would like to change it to use something like this.

[Kayen]

Function will probably end up looking something like this.

bool Client::CheckDoubleAttack(bool tripleAttack) {

	//Check for bonuses that give you a double attack chance regardless of skill (ie Bestial Frenzy/Harmonious Attack AA)
	uint16 bonusGiveDA = aabonuses.GiveDoubleAttack + spellbonuses.GiveDoubleAttack + itembonuses.GiveDoubleAttack;

	if(!HasSkill(DOUBLE_ATTACK) && !bonusGiveDA)
		return false;
	
	int chance = 0;
	
	int8 classtype = GetClass();
	
	uint16 skill = GetSkill(DOUBLE_ATTACK);

	sint16 bonusDA = aabonuses.DoubleAttackChance + spellbonuses.DoubleAttackChance + itembonuses.DoubleAttackChance;
	sint16 skillmod = 0; //TODO: Apply all worn skill mods, spell skill mods.

	//Use skill calculations otherwise, if you only have AA applied GiveDoubleAttack chance then use that value as the base.
	if (skill)
		chance = ( (skill*(100+skillmod/100) + GetLevel()) * (100+bonusDA+bonusGiveDA /100)) /500
	else 
		chance = bonusGiveDA + (bonusGiveDA * (100+bonusDA/100));

	//Live now uses a static Triple Attack skill (lv 46 = 2% lv 60 = 20%) - We do not have this skill on EMU ATM.
	//A reasonable forumla would then be TA = 20% * chance
	if(tripleAttack) {
		// Only some Double Attack classes get Triple Attack [This is already checked in client_processes.cpp]
		sint16 triple_bonus = spellbonuses.TripleAttackChance + itembonuses.TripleAttackChance;
		chance *= 20 + triple_bonus /100;
	}
	else 
		return false;
	
	
	if((MakeRandomInt(0, 100) < chance))) 
		return true;
	
	return false;
}