Add item attribute to affect hit chance

data/conf/equipment.xsd

@@ -11,6 +11,7 @@
 						<element name="damagetype" type="Q1:attribute" minOccurs="0" maxOccurs="unbounded"/>
 						<element name="statusattack" type="Q1:attribute" minOccurs="0" maxOccurs="unbounded"/>
 						<element name="statusresist" type="Q1:statusresist" minOccurs="0" maxOccurs="unbounded"/>
+						<element name="accuracy_bonus" type="Q1:attribute" minOccurs="0" maxOccurs="1"/>
 					</sequence>
 				</extension>
 			</complexContent>

src/games/stendhal/server/entity/item/Item.java

@@ -1,6 +1,6 @@
 /* $Id$ */
 /***************************************************************************
- *                   (C) Copyright 2003-2023 - Marauroa                    *
+ *                   (C) Copyright 2003-2024 - Marauroa                    *
  ***************************************************************************
  ***************************************************************************
  *                                                                         *
@@ -170,6 +170,9 @@ public static void generateRPClass() {
 		// Some items have ranged attack values
 		entity.addAttribute("ratk", Type.SHORT, Definition.HIDDEN);
 
+		// alters weapon accuracy by a percentage
+		entity.addAttribute("accuracy_bonus", Type.FLOAT, Definition.HIDDEN);
+
 		// Some items indicate how often you can attack.
 		entity.addAttribute("rate", Type.SHORT, Definition.HIDDEN);
 
@@ -871,6 +874,10 @@ public String describe() {
 				stats.append("%");
 			}
 		}
+		if (has("accuracy_bonus")) {
+			stats.append(" ACCURACY-BONUS: ");
+			stats.append(((getDouble("accuracy_bonus") * 100) + "%").replaceFirst("\\.[0]+%$", "%"));
+		}
 
 		if (has("min_level")) {
 			stats.append(" MIN-LEVEL: ");

src/games/stendhal/server/entity/player/Player.java

@@ -1,6 +1,6 @@
 /* $Id$ */
 /***************************************************************************
- *                    (C) Copyright 2003-2023 - Arianne                    *
+ *                    (C) Copyright 2003-2024 - Arianne                    *
  ***************************************************************************
  ***************************************************************************
  *                                                                         *
@@ -3212,6 +3212,21 @@ public int getMaxSlotSize(String slot) {
 		return Integer.parseInt(values[0]) * Integer.parseInt(values[1]);
 	}
 
+	/**
+	 * Retrieves amount to apply to player ATK to adjust hit chance.
+	 *
+	 * @return
+	 *   Value of player ATK multiplied by percentage defined in item "accuracy_bonus" attribute.
+	 */
+	private int getAccuracyBonus() {
+		double accBonus = 0;
+		for (final Item equip: getAllEquipment()) {
+			accBonus += equip.has("accuracy_bonus") ? equip.getDouble("accuracy_bonus") : 0;
+		}
+		// base on raw uncapped value
+		return (int) Math.round(this.atk * accBonus);
+	}
+
 	/**
 	 * This handicap increases chance that a player can hit an enemy to
 	 * make the game feel more fair. Hit chance is based on raw atk stat,
@@ -3224,7 +3239,8 @@ public int getMaxSlotSize(String slot) {
 	protected int calculateRiskForCanHit(final int roll, final int defenderDEF,
 			final int attackerATK) {
 		// use 30 as multiple for players instead of 20
-		return ((int) Math.round(HIT_CHANCE_MULTIPLIER * 1.5)) * attackerATK - roll * defenderDEF;
+		return ((int) Math.round(HIT_CHANCE_MULTIPLIER * 1.5)) * (attackerATK + this.getAccuracyBonus())
+				- roll * defenderDEF;
 	}
 
 	/**