Medical Engine - Improve damage calculation for explosive-resistant armor (#9216)

* scale armor damage using passthrough

* add - to comment

Co-authored-by: Jouni Järvinen <rautamiekka@users.noreply.github.com>

* improve condition

Co-authored-by: Jouni Järvinen <rautamiekka@users.noreply.github.com>

* remove extra brackets

Co-authored-by: Jouni Järvinen <rautamiekka@users.noreply.github.com>

* remove extra brackets

* fix damage sorting

* whitespace

* comment

* fix function header

* fix infinite armor when no item equipped

* cleanup

* more cleanup

* name

* don't scale structural damage

* add setting

* fix key name

* add cap to passThrough

* fix script error in setting

---------

Co-authored-by: GhostIsSpooky <69561145+Salluci@users.noreply.github.com>
Co-authored-by: Jouni Järvinen <rautamiekka@users.noreply.github.com>

addons/medical_engine/functions/fnc_getHitpointArmor.sqf

@@ -1,6 +1,6 @@
 #include "..\script_component.hpp"
 /*
- * Author: Pterolatypus
+ * Author: Pterolatypus, LinkIsGrim
  * Checks a unit's equipment to calculate the total armor on a hitpoint.
  *
  * Arguments:
@@ -8,7 +8,7 @@
  * 1: Hitpoint <STRING>
  *
  * Return Value:
- * Total armor for the given hitpoint <NUMBER>
+ * Total armor and scaled armor for the given hitpoint <ARRAY of NUMBER>
  *
  * Example:
  * [player, "HitChest"] call ace_medical_engine_fnc_getHitpointArmor
@@ -32,16 +32,19 @@ private _gear = [
 
 private _rags = _gear joinString "$";
 private _var = format [QGVAR(armorCache$%1), _hitpoint];
-_unit getVariable [_var, [""]] params ["_prevRags", "_armor"];
+_unit getVariable [_var, ["", 0, 0]] params ["_prevRags", "_armor", "_armorScaled"];
 
 if (_rags != _prevRags) then {
     _armor = 0;
+    _armorScaled = 0;
 
     {
-        _armor = _armor + ([_x, _hitpoint] call FUNC(getItemArmor));
+        ([_x, _hitpoint] call FUNC(getItemArmor)) params ["_itemArmor", "_itemArmorScaled"];
+        _armor = _armor + _itemArmor;
+        _armorScaled = _armorScaled + _itemArmorScaled;
     } forEach _gear;
 
-    _unit setVariable [_var, [_rags, _armor]];
+    _unit setVariable [_var, [_rags, _armor, _armorScaled]];
 };
 
-_armor // return
+[_armor, _armorScaled] // return

addons/medical_engine/functions/fnc_getItemArmor.sqf

@@ -1,14 +1,14 @@
 #include "..\script_component.hpp"
 /*
- * Author: Pterolatypus
- * Returns the armor value the given item provides to a particular hitpoint, either from a cache or by reading the item config.
+ * Author: Pterolatypus, LinkIsGrim
+ * Returns the regular and scaled armor values the given item provides to a particular hitpoint, either from a cache or by reading the item config.
  *
  * Arguments:
  * 0: Item Class <STRING>
  * 1: Hitpoint <STRING>
  *
  * Return Value:
- * Item armor for the given hitpoint <NUMBER>
+ * Regular and scaled item armor for the given hitpoint <ARRAY of NUMBER>
  *
  * Example:
  * ["V_PlateCarrier_rgr", "HitChest"] call ace_medical_engine_fnc_getItemArmor
@@ -19,13 +19,16 @@
 params ["_item", "_hitpoint"];
 
 private _key = format ["%1$%2", _item, _hitpoint];
-private _armor = GVAR(armorCache) get _key;
+private _return = GVAR(armorCache) get _key;
 
-if (isNil "_armor") then {
+if (isNil "_return") then {
+    private _armor = 0;
+    private _armorScaled = 0;
+    private _passThrough = 1;
     TRACE_2("Cache miss",_item,_hitpoint);
     if ("" in [_item, _hitpoint]) exitWith {
-        _armor = 0;
-        GVAR(armorCache) set [_key, _armor];
+        _return = [_armor, _armorScaled];
+        GVAR(armorCache) set [_key, _return];
     };
 
     private _itemInfo = configFile >> "CfgWeapons" >> _item >> "ItemInfo";
@@ -38,15 +41,24 @@ if (isNil "_armor") then {
         } else {
             private _entry = _unitCfg >> "HitPoints" >> _hitpoint;
             _armor = getNumber (_unitCfg >> "armor") * (1 max getNumber (_entry >> "armor"));
+            _passThrough = 0.1 max getNumber (_entry >> "passThrough") min 1; // prevent dividing by 0
         };
     } else {
         private _condition = format ["getText (_x >> 'hitpointName') == '%1'", _hitpoint];
         private _entry = configProperties [_itemInfo >> "HitpointsProtectionInfo", _condition] param [0, configNull];
-
+        if (!isNull _entry) then {
             _armor = getNumber (_entry >> "armor");
+            _passThrough = 0.1 max getNumber (_entry >> "passThrough") min 1;
+        };
     };
 
-    GVAR(armorCache) set [_key, _armor];
+    // Scale armor using passthrough to fix explosive-resistant armor (#9063)
+    // Skip scaling for items that don't cover the hitpoint to prevent infinite armor
+    if (_armor isNotEqualTo 0) then {
+        _armorScaled = (log (_armor / _passThrough)) * 10;
+    };
+    _return = [_armor, _armorScaled];
+    GVAR(armorCache) set [_key, _return];
 };
 
-_armor // return
+_return // return

addons/medical_engine/functions/fnc_handleDamage.sqf

@@ -32,9 +32,16 @@ if (_hitPoint isEqualTo "") then {
 if !(isDamageAllowed _unit && {_unit getVariable [QEGVAR(medical,allowDamage), true]}) exitWith {_oldDamage};
 
 private _newDamage = _damage - _oldDamage;
-// Get armor value of hitpoint and calculate damage before armor
-private _armor = [_unit, _hitpoint] call FUNC(getHitpointArmor);
+// Get scaled armor value of hitpoint and calculate damage before armor
+// We scale using passThrough to handle explosive-resistant armor properly (#9063)
+// We need realDamage to determine which limb was hit correctly
+[_unit, _hitpoint] call FUNC(getHitpointArmor) params ["_armor", "_armorScaled"];
 private _realDamage = _newDamage * _armor;
+if (_hitPoint isNotEqualTo "#structural") then {
+    private _armorCoef = _armor/_armorScaled;
+    private _damageCoef = linearConversion [0, 1, GVAR(damagePassThroughEffect), 1, _armorCoef];
+    _newDamage = _newDamage * _damageCoef;
+};
 TRACE_4("Received hit",_hitpoint,_ammo,_newDamage,_realDamage);
 
 // Drowning doesn't fire the EH for each hitpoint so the "ace_hdbracket" code never runs
@@ -101,8 +108,9 @@ if (_hitPoint isEqualTo "ace_hdbracket") exitWith {
     private _damageLeftLeg = _unit getVariable [QGVAR($HitLeftLeg), [0,0]];
     private _damageRightLeg = _unit getVariable [QGVAR($HitRightLeg), [0,0]];
 
-    // Find hit point that received the maxium damage
+    // Find hit point that received the maximum damage
     // Priority used for sorting if incoming damage is equal
+    // _realDamage, priority, _newDamage, body part name
     private _allDamages = [
         [_damageHead select 0,       PRIORITY_HEAD,       _damageHead select 1,       "Head"],
         [_damageBody select 0,       PRIORITY_BODY,       _damageBody select 1,       "Body"],

addons/medical_engine/initSettings.sqf

@@ -6,3 +6,12 @@
     true,
     true
 ] call CBA_fnc_addSetting;
+
+[
+    QGVAR(damagePassThroughEffect),
+    "SLIDER",
+    [LSTRING(damagePassThroughEffect_displayName), LSTRING(damagePassThroughEffect_description)],
+    ELSTRING(medical,Category),
+    [0, 1, 1, 2, true],
+    true
+] call CBA_fnc_addSetting;

addons/medical_engine/stringtable.xml

@@ -23,5 +23,11 @@
             <Chinesesimp>控制乘员是否受到车辆碰撞的伤害。</Chinesesimp>
             <Korean>차량 충돌로 인해 탑승인원들이 피해를 받을 지 결정합니다.</Korean>
         </Key>
+        <Key ID="STR_ACE_Medical_Engine_damagePassThroughEffect_displayName">
+            <English>Armor PassThrough Effect</English>
+        </Key>
+        <Key ID="STR_ACE_Medical_Engine_damagePassThroughEffect_description">
+            <English>Controls effect of armor 'passThrough' on final damage. Makes high armor values, like ones used in GL rigs, less effective.\nUse 0% for pre 3.16.0 armor behavior.\nOnly touch this if you know what you're doing!</English>
+        </Key>
     </Package>
 </Project>