[Minor] Adjust Gatling weapon selection (#2133)

the current gatling weapon selection logic will only check if the target
is vulnerable to odd weapon, and simply switch to secondary if it
doesn't. This will create issue when both odd and even weapons are not
supposed to attack the target. This pull request make it follow the
process that other weapon selection is using, which is checking if even
weapon is available first and then odd weapon

also fixed & regulated a few things in weapon selection

Author: Coronia

src/Ext/Techno/Hooks.Firing.cpp

@@ -1,4 +1,4 @@
-#include "Body.h"
+#include "Body.h"
 
 #include <Ext/Anim/Body.h>
 #include <Ext/Building/Body.h>
@@ -199,59 +199,68 @@ DEFINE_HOOK(0x6F3432, TechnoClass_WhatWeaponShouldIUse_Gattling, 0xA)
 	auto const pTargetTechno = abstract_cast<TechnoClass*>(pTarget);
 	const int oddWeaponIndex = 2 * pThis->CurrentGattlingStage;
 	const int evenWeaponIndex = oddWeaponIndex + 1;
-	int chosenWeaponIndex = oddWeaponIndex;
 	const int eligibleWeaponIndex = TechnoExt::PickWeaponIndex(pThis, pTargetTechno, pTarget, oddWeaponIndex, evenWeaponIndex, true);
 
 	if (eligibleWeaponIndex != -1)
 	{
-		chosenWeaponIndex = eligibleWeaponIndex;
+		R->EAX(eligibleWeaponIndex);
+		return UseWeaponIndex;
 	}
-	else if (pTargetTechno)
+
+	int chosenWeaponIndex = oddWeaponIndex;
+
+	if (pTargetTechno)
 	{
 		auto const pTargetExt = TechnoExt::ExtMap.Find(pTargetTechno);
-		auto const pWeaponOdd = pThis->GetWeapon(oddWeaponIndex)->WeaponType;
 		auto const pWeaponEven = pThis->GetWeapon(evenWeaponIndex)->WeaponType;
-		bool skipRemainingChecks = false;
+		auto const pShield = pTargetExt->Shield.get();
+		auto const armor = pTargetTechno->GetTechnoType()->Armor;
+		const bool inAir = pTargetTechno->IsInAir();
+		const bool isUnderground = pTargetTechno->InWhichLayer() == Layer::Underground;
 
-		if (const auto pShield = pTargetExt->Shield.get())
-		{
-			if (pShield->IsActive() && !pShield->CanBeTargeted(pWeaponOdd))
+		auto isWeaponValid = [&](WeaponTypeClass* pWeapon)
 			{
-				chosenWeaponIndex = evenWeaponIndex;
-				skipRemainingChecks = true;
-			}
+				if (inAir && !pWeapon->Projectile->AA)
+					return false;
+				if (isUnderground && !BulletTypeExt::ExtMap.Find(pWeapon->Projectile)->AU)
+					return false;
+				if (pShield && pShield->IsActive() && !pShield->CanBeTargeted(pWeapon))
+					return false;
+				if (GeneralUtils::GetWarheadVersusArmor(pWeapon->Warhead, armor) == 0.0)
+					return false;
+				return true;
+			};
+
+		// check even weapon first
+
+		if (!isWeaponValid(pWeaponEven))
+		{
+			R->EAX(chosenWeaponIndex);
+			return UseWeaponIndex;
 		}
 
-		if (!skipRemainingChecks)
+		// handle naval targeting
+
+		if (!pTargetTechno->OnBridge && !inAir)
 		{
-			if (GeneralUtils::GetWarheadVersusArmor(pWeaponOdd->Warhead, pTargetTechno->GetTechnoType()->Armor) == 0.0)
-			{
-				chosenWeaponIndex = evenWeaponIndex;
-			}
-			else if (pTargetTechno->InWhichLayer() == Layer::Underground)
+			auto const landType = pTargetTechno->GetCell()->LandType;
+
+			if (landType == LandType::Water || landType == LandType::Beach)
 			{
-				if (BulletTypeExt::ExtMap.Find(pWeaponEven->Projectile)->AU && !BulletTypeExt::ExtMap.Find(pWeaponOdd->Projectile)->AU)
+				if (pThis->SelectNavalTargeting(pTargetTechno) == 1)
 					chosenWeaponIndex = evenWeaponIndex;
-			}
-			else
-			{
-				auto const landType = pTargetTechno->GetCell()->LandType;
-				const bool isOnWater = (landType == LandType::Water || landType == LandType::Beach) && !pTargetTechno->IsInAir();
 
-				if (!pTargetTechno->OnBridge && isOnWater && pThis->SelectNavalTargeting(pTargetTechno) == 2)
-				{
-					chosenWeaponIndex = evenWeaponIndex;
-				}
-				else if (pTargetTechno->IsInAir() && !pWeaponOdd->Projectile->AA && pWeaponEven->Projectile->AA)
-				{
-					chosenWeaponIndex = evenWeaponIndex;
-				}
-				else if (pThis->GetTechnoType()->LandTargeting == LandTargetingType::Land_Secondary)
-				{
-					chosenWeaponIndex = evenWeaponIndex;
-				}
+				R->EAX(chosenWeaponIndex);
+				return UseWeaponIndex;
 			}
 		}
+
+		// check odd weapon
+
+		auto const pWeaponOdd = pThis->GetWeapon(oddWeaponIndex)->WeaponType;
+
+		if (!isWeaponValid(pWeaponOdd) || pThis->GetTechnoType()->LandTargeting == LandTargetingType::Land_Secondary)
+			chosenWeaponIndex = evenWeaponIndex;
 	}
 
 	R->EAX(chosenWeaponIndex);

src/Ext/Techno/Hooks.WeaponRange.cpp

@@ -196,7 +196,7 @@ DEFINE_HOOK(0x6FC3A1, TechnoClass_CanFire_InBunkerRangeCheck, 0x5)
 	GET(TechnoClass*, pThis, EBP);
 	GET(WeaponTypeClass*, pWeapon, EDI);
 
-	if (pThis->WhatAmI() == AbstractType::Unit && WeaponTypeExt::GetRangeWithModifiers(pWeapon, pThis) < 384.0)
+	if (pThis->WhatAmI() == AbstractType::Unit && WeaponTypeExt::GetRangeWithModifiers(pWeapon, pThis) < 384)
 		return CannotFire;
 
 	return ContinueChecks;

src/Ext/TechnoType/Body.cpp

@@ -158,9 +158,6 @@ int TechnoTypeExt::ExtData::SelectMultiWeapon(TechnoClass* const pThis, Abstract
 
 	if (const auto pTargetTechno = abstract_cast<TechnoClass*, true>(pTarget))
 	{
-		if (pTargetTechno->Health <= 0 || !pTargetTechno->IsAlive)
-			return 0;
-
 		bool getNavalTargeting = false;
 
 		auto checkSecondary = [&](int weaponIndex) -> bool
@@ -217,9 +214,8 @@ int TechnoTypeExt::ExtData::SelectMultiWeapon(TechnoClass* const pThis, Abstract
 		};
 
 		const LandType landType = pTargetTechno->GetCell()->LandType;
-		const bool targetOnWater = landType == LandType::Water || landType == LandType::Beach;
 
-		if (!pTargetTechno->OnBridge && targetOnWater)
+		if (!pTargetTechno->OnBridge && (landType == LandType::Water || landType == LandType::Beach) && !pTargetTechno->IsInAir())
 		{
 			const int result = pThis->SelectNavalTargeting(pTargetTechno);