runelite-api: add combat level formula to Experience

runelite-api/src/main/java/net/runelite/api/Experience.java

@@ -88,4 +88,27 @@ public class Experience
 
 		return high + 2;
 	}
+
+	public static double getCombatLevelPrecise(int attackLevel, int strengthLevel,
+		int defenceLevel, int hitpointsLevel, int magicLevel,
+		int rangeLevel, int prayerLevel)
+	{
+		double melee = 0.25 * (defenceLevel + hitpointsLevel + Math.floor(prayerLevel / 2))
+			+ 0.325 * (attackLevel + strengthLevel);
+
+		double range = 0.25 * (defenceLevel + hitpointsLevel + Math.floor(prayerLevel / 2))
+			+ 0.325 * (Math.floor(rangeLevel / 2));
+
+		double magic = 0.25 * (defenceLevel + hitpointsLevel + Math.floor(prayerLevel / 2))
+			+ 0.325 * (Math.floor(magicLevel / 2));
+
+		return Math.max(melee, Math.max(range, magic));
+	}
+
+	public static int getCombatLevel(int attackLevel, int strengthLevel,
+		int defenceLevel, int hitpointsLevel, int magicLevel,
+		int rangeLevel, int prayerLevel)
+	{
+		return (int) getCombatLevelPrecise(attackLevel, strengthLevel, defenceLevel, hitpointsLevel, magicLevel, rangeLevel, prayerLevel);
+	}
 }

runelite-api/src/test/java/net/runelite/api/ExperienceTest.java

@@ -54,8 +54,14 @@ public class ExperienceTest
 
 		level = Experience.getLevelForXp(0);
 		Assert.assertEquals(1, level);
-		
+
 		level = Experience.getLevelForXp(200_000_000);
 		Assert.assertEquals(126, level);
 	}
+
+	@Test
+	public void testGetCombatLevel()
+	{
+		Assert.assertEquals(126, Experience.getCombatLevel(99, 99, 99, 99, 70, 42, 98));
+	}
 }