v2.0.0: added an ability for sneak attack weapons

core/src/main/assets/messages/items/items.properties

@@ -1482,6 +1482,8 @@ items.weapon.enchantments.vampiric.desc=This powerful enchantment leeches life f
 ###melee weapons
 items.weapon.melee.assassinsblade.name=assassin's blade
 items.weapon.melee.assassinsblade.stats_desc=This weapon is stronger against unaware enemies.
+items.weapon.melee.assassinsblade.ability_name=sneak
+items.weapon.melee.assassinsblade.ability_desc=The duelist can _sneak_ while wielding an assassin's blade. This ability lets the duelist blink up to 3 tiles away and grants her 1 turn of invisibility, but costs 2 charges.
 items.weapon.melee.assassinsblade.desc=A small wavy blade made of obsidian, difficult to use despite being lightweight, but deadly if it finds the right mark.
 
 items.weapon.melee.battleaxe.name=battle axe
@@ -1494,10 +1496,14 @@ items.weapon.melee.crossbow.desc=A fairly intricate weapon which shoots bolts at
 
 items.weapon.melee.dagger.name=dagger
 items.weapon.melee.dagger.stats_desc=This weapon is stronger against unaware enemies.
+items.weapon.melee.dagger.ability_name=sneak
+items.weapon.melee.dagger.ability_desc=The duelist can _sneak_ while wielding a dagger. This ability lets the duelist blink up to 5 tiles away and grants her 1 turn of invisibility, but costs 2 charges.
 items.weapon.melee.dagger.desc=A simple iron dagger with a worn wooden handle.
 
 items.weapon.melee.dirk.name=dirk
 items.weapon.melee.dirk.stats_desc=This weapon is stronger against unaware enemies.
+items.weapon.melee.dirk.ability_name=sneak
+items.weapon.melee.dirk.ability_desc=The duelist can _sneak_ while wielding a dirk. This ability lets the duelist blink up to 4 tiles away and grants her 1 turn of invisibility, but costs 2 charges.
 items.weapon.melee.dirk.desc=A longer thrusting dagger, gives a bit more steel to plunge into foes.
 
 items.weapon.melee.flail.name=flail

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/items/weapon/melee/AssassinsBlade.java

@@ -25,6 +25,7 @@ import com.shatteredpixel.shatteredpixeldungeon.Assets;
 import com.shatteredpixel.shatteredpixeldungeon.actors.Char;
 import com.shatteredpixel.shatteredpixeldungeon.actors.hero.Hero;
 import com.shatteredpixel.shatteredpixeldungeon.actors.mobs.Mob;
+import com.shatteredpixel.shatteredpixeldungeon.messages.Messages;
 import com.shatteredpixel.shatteredpixeldungeon.sprites.ItemSpriteSheet;
 import com.watabou.utils.Random;
 
@@ -65,4 +66,19 @@ public class AssassinsBlade extends MeleeWeapon {
 		return super.damageRoll(owner);
 	}
 
+	@Override
+	public int abilityChargeUse() {
+		return 2;
+	}
+
+	@Override
+	public String targetingPrompt() {
+		return Messages.get(this, "prompt");
+	}
+
+	@Override
+	protected void duelistAbility(Hero hero, Integer target) {
+		Dagger.sneakAbility(hero, target, 3, this);
+	}
+
 }

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/items/weapon/melee/Dagger.java

@@ -22,10 +22,23 @@
 package com.shatteredpixel.shatteredpixeldungeon.items.weapon.melee;
 
 import com.shatteredpixel.shatteredpixeldungeon.Assets;
+import com.shatteredpixel.shatteredpixeldungeon.Dungeon;
+import com.shatteredpixel.shatteredpixeldungeon.actors.Actor;
 import com.shatteredpixel.shatteredpixeldungeon.actors.Char;
+import com.shatteredpixel.shatteredpixeldungeon.actors.buffs.Buff;
+import com.shatteredpixel.shatteredpixeldungeon.actors.buffs.Invisibility;
 import com.shatteredpixel.shatteredpixeldungeon.actors.hero.Hero;
 import com.shatteredpixel.shatteredpixeldungeon.actors.mobs.Mob;
+import com.shatteredpixel.shatteredpixeldungeon.effects.CellEmitter;
+import com.shatteredpixel.shatteredpixeldungeon.effects.Speck;
+import com.shatteredpixel.shatteredpixeldungeon.messages.Messages;
+import com.shatteredpixel.shatteredpixeldungeon.scenes.GameScene;
 import com.shatteredpixel.shatteredpixeldungeon.sprites.ItemSpriteSheet;
+import com.shatteredpixel.shatteredpixeldungeon.utils.BArray;
+import com.shatteredpixel.shatteredpixeldungeon.utils.GLog;
+import com.watabou.noosa.audio.Sample;
+import com.watabou.utils.Callback;
+import com.watabou.utils.PathFinder;
 import com.watabou.utils.Random;
 
 public class Dagger extends MeleeWeapon {
@@ -67,4 +80,51 @@ public class Dagger extends MeleeWeapon {
 		return super.damageRoll(owner);
 	}
 
+	@Override
+	public int abilityChargeUse() {
+		return 2;
+	}
+
+	@Override
+	public String targetingPrompt() {
+		return Messages.get(this, "prompt");
+	}
+
+	@Override
+	protected void duelistAbility(Hero hero, Integer target) {
+		sneakAbility(hero, target, 5, this);
+	}
+
+	public static void sneakAbility(Hero hero, Integer target, int maxDist, MeleeWeapon wep){
+		if (target == null) {
+			return;
+		}
+
+		if (Actor.findChar(target) != null || !Dungeon.level.heroFOV[target]) {
+			GLog.w(Messages.get(wep, "ability_bad_position"));
+			return;
+		}
+
+		PathFinder.buildDistanceMap(Dungeon.hero.pos, BArray.not(Dungeon.level.solid, null), maxDist);
+		if (PathFinder.distance[target] == Integer.MAX_VALUE) {
+			GLog.w(Messages.get(wep, "ability_bad_position"));
+			return;
+		}
+
+		Buff.affect(hero, Invisibility.class, Math.max(1, 1/hero.speed()));
+		hero.spendAndNext(1/hero.speed());
+		wep.onAbilityUsed(hero);
+
+		Dungeon.hero.sprite.turnTo( Dungeon.hero.pos, target);
+		Dungeon.hero.pos = target;
+		Dungeon.level.occupyCell(Dungeon.hero);
+		Dungeon.observe();
+		GameScene.updateFog();
+		Dungeon.hero.checkVisibleMobs();
+
+		Dungeon.hero.sprite.place( Dungeon.hero.pos );
+		CellEmitter.get( Dungeon.hero.pos ).burst( Speck.factory( Speck.WOOL ), 6 );
+		Sample.INSTANCE.play( Assets.Sounds.PUFF );
+	}
+
 }

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/items/weapon/melee/Dirk.java

@@ -25,6 +25,7 @@ import com.shatteredpixel.shatteredpixeldungeon.Assets;
 import com.shatteredpixel.shatteredpixeldungeon.actors.Char;
 import com.shatteredpixel.shatteredpixeldungeon.actors.hero.Hero;
 import com.shatteredpixel.shatteredpixeldungeon.actors.mobs.Mob;
+import com.shatteredpixel.shatteredpixeldungeon.messages.Messages;
 import com.shatteredpixel.shatteredpixeldungeon.sprites.ItemSpriteSheet;
 import com.watabou.utils.Random;
 
@@ -65,4 +66,19 @@ public class Dirk extends MeleeWeapon {
 		return super.damageRoll(owner);
 	}
 
+	@Override
+	public int abilityChargeUse() {
+		return 2;
+	}
+
+	@Override
+	public String targetingPrompt() {
+		return Messages.get(this, "prompt");
+	}
+
+	@Override
+	protected void duelistAbility(Hero hero, Integer target) {
+		Dagger.sneakAbility(hero, target, 4, this);
+	}
+
 }