Refactor player hp percentage calculation to avoid C4244 warnings

Source/control.cpp

@@ -582,12 +582,7 @@ void DrawLifeFlask(const CelOutputBuffer &out)
 {
 	auto &myPlayer = plr[myplr];
 
-	double p = 0.0;
-	if (myPlayer._pMaxHP > 0) {
-		p = (double)myPlayer._pHitPoints / (double)myPlayer._pMaxHP * 80.0;
-	}
-	myPlayer._pHPPer = p;
-	int filled = myPlayer._pHPPer;
+	int filled = myPlayer.UpdateHitPointPercentage();
 
 	if (filled > 80)
 		filled = 80;
@@ -606,12 +601,7 @@ void UpdateLifeFlask(const CelOutputBuffer &out)
 {
 	auto &myPlayer = plr[myplr];
 
-	double p = 0.0;
-	if (myPlayer._pMaxHP > 0) {
-		p = (double)myPlayer._pHitPoints / (double)myPlayer._pMaxHP * 80.0;
-	}
-	int filled = p;
-	myPlayer._pHPPer = filled;
+	int filled = myPlayer.UpdateHitPointPercentage();
 
 	if (filled > 69)
 		filled = 69;
@@ -645,7 +635,7 @@ void control_update_life_mana()
 	int maxMana = std::max(myPlayer._pMaxMana, 0);
 	int mana = std::max(myPlayer._pMana, 0);
 	myPlayer._pManaPer = maxMana != 0 ? ((double)mana / (double)maxMana * 80.0) : 0;
-	myPlayer._pHPPer = (double)myPlayer._pHitPoints / (double)myPlayer._pMaxHP * 80.0;
+	myPlayer.UpdateHitPointPercentage();
 }
 
 void UpdateManaFlask(const CelOutputBuffer &out)

Source/player.h

@@ -402,6 +402,27 @@ struct PlayerStruct {
 	 * @brief Resets all Data of the current PlayerStruct
 	 */
 	void Reset();
+
+	/**
+	 * @brief Calculates the players current Hit Points as a percentage of their max HP and stores it for later reference
+	 *
+	 * The stored value is unused...
+	 * @see _pHPPer
+	 * @return The players current hit points as a percentage of their maximum (from 0 to 80%)
+	*/
+	int UpdateHitPointPercentage()
+	{
+		if (_pMaxHP <= 0) { // divide by zero guard
+			_pHPPer = 0;
+		} else {
+			// Maximum achievable HP is approximately 1200. Diablo uses fixed point integers where the last 6 bits are
+			// fractional values. This means that we will never overflow HP values normally by doing this multiplication
+			// as the max value is representable in 17 bits and the multiplication result will be at most 23 bits
+			_pHPPer = _pHitPoints * 80 / _pMaxHP;
+		}
+
+		return _pHPPer;
+	}
 };
 
 extern int myplr;