feat: Add magic bullets

src/TerraSharp/Core/Hotkeys.cs

@@ -56,6 +56,7 @@ public static class Hotkeys
         Toggle("Combat", "FreezeEnemies", "Freeze Enemies", () => Settings.FreezeEnemies, v => Settings.FreezeEnemies = v),
         Toggle("Combat", "WeakenEnemies", "Weaken Enemies", () => Settings.WeakenEnemies, v => Settings.WeakenEnemies = v),
         Toggle("Combat", "RapidAttack", "Rapid Attack", () => Settings.RapidAttack, v => Settings.RapidAttack = v),
+        Toggle("Combat", "MagicBullets", "Magic Bullets", () => Settings.MagicBullets, v => Settings.MagicBullets = v),
         new("Combat", "GatherAll", "Gather All Enemies", CombatFeatures.GatherAll),
         new("Combat", "KillAll", "Kill All Enemies", CombatFeatures.KillAll),
 

src/TerraSharp/Core/Settings.Json.cs

@@ -58,6 +58,7 @@ public static partial class Settings
         [nameof(ShotPreview)] = "Combat.Aim.ShotPreview",
         [nameof(AimFov)] = "Combat.Aim.CursorRadius",
         [nameof(AimRange)] = "Combat.Aim.Range",
+        [nameof(MagicBullets)] = "Combat.MagicBullets",
 
         [nameof(InstantBreak)] = "Items.InstantBreak",
         [nameof(InfItems)] = "Items.InfiniteItems",

src/TerraSharp/Core/Settings.cs

@@ -35,7 +35,7 @@ public static partial class Settings
     public static bool KillAura, HitMagnet, FreezeEnemies, WeakenEnemies;
     public static float KillAuraRange = 20f, HitMagnetRange = 30f;
     public static int KillAuraInterval = 10;
-    public static bool Aimbot, AimPrediction = true, AimDrawTarget = true, AutoAttack, AimExact = true, ShotPreview;
+    public static bool Aimbot, AimPrediction = true, AimDrawTarget = true, AutoAttack, AimExact = true, ShotPreview, MagicBullets;
     public static float AimFov = 250f, AimRange = 60f;
 
     public static bool InstantBreak, InfItems, ItemVacuum, AutoSell, BankButtons = true;

src/TerraSharp/Features/Combat/MagicBullets.cs

@@ -0,0 +1,69 @@
+using System;
+using Microsoft.Xna.Framework;
+using Terraria;
+using Terraria.ID;
+using TerraSharp.Core;
+using TerraSharp.Simulation;
+
+namespace TerraSharp.Features.Combat;
+
+public static class MagicBullets
+{
+    const float MinSpeed = 8f;
+    const int GrappleStyle = 7, YoyoStyle = 99, FlailStyle = 15;
+
+    // Projectile type per slot while steered, 0 otherwise.
+    static readonly int[] Steered = new int[Main.maxProjectiles];
+
+    public static bool IsSteered(int slot) => Steered[slot] != 0 && Steered[slot] == Main.projectile[slot].type;
+
+    static bool Eligible(Projectile projectile) => projectile is { friendly: true, hostile: false, minion: false, sentry: false, bobber: false, npcProj: false, damage: > 0 } && projectile.aiStyle is not (GrappleStyle or YoyoStyle or FlailStyle) && !Main.projPet[projectile.type] && !ProjectileID.Sets.IsAWhip[projectile.type] && !Sandbox.Held(projectile);
+
+    // Projectile.AI postfix for the local player's projectiles.
+    public static void PostAI(Projectile projectile)
+    {
+        int slot = projectile.whoAmI;
+        NPC? target = Eligible(projectile) ? TargetFor(projectile) : null;
+        if (target is null)
+        {
+            if (IsSteered(slot) && ContentSamples.ProjectilesByType.TryGetValue(projectile.type, out Projectile? sample))
+                projectile.tileCollide = sample.tileCollide;
+            Steered[slot] = 0;
+            return;
+        }
+
+        Vector2 offset = target.Center - projectile.Center;
+        if (offset.LengthSquared() < 1f)
+            return;
+
+        projectile.velocity = Vector2.Normalize(offset) * Math.Max(projectile.velocity.Length(), MinSpeed);
+        projectile.tileCollide = false;
+        Steered[slot] = projectile.type;
+    }
+
+    static NPC? TargetFor(Projectile projectile)
+    {
+        if (Aimbot.Target is { } locked && Hostility.IsDamageable(locked))
+            return locked;
+
+        Player player = Main.player[projectile.owner];
+        float range = Settings.AimRange * 16f, rangeSq = range * range;
+        NPC? best = null;
+        float bestDistance = float.MaxValue;
+        for (int i = 0; i < Main.maxNPCs; i++)
+        {
+            NPC npc = Main.npc[i];
+            if (!Hostility.IsDamageable(npc) || Vector2.DistanceSquared(npc.Center, player.Center) > rangeSq)
+                continue;
+
+            float distance = Vector2.DistanceSquared(npc.Center, projectile.Center);
+            if (distance < bestDistance)
+            {
+                bestDistance = distance;
+                best = npc;
+            }
+        }
+
+        return best;
+    }
+}

src/TerraSharp/Patches/HookRegistry.cs

@@ -21,6 +21,7 @@ internal sealed class HookRegistry : IDisposable
             MainPatches.Install(hooks);
             PlayerPatches.Install(hooks);
             NpcPatches.Install(hooks);
+            ProjectilePatches.Install(hooks);
             DamageNumberPatches.Install(hooks);
             VisionPatches.Install(hooks);
             SpawnRatePatch.Install(hooks);

src/TerraSharp/Patches/ProjectilePatches.cs

@@ -0,0 +1,22 @@
+using System;
+using Terraria;
+using TerraSharp.Core;
+using TerraSharp.Features.Combat;
+using TerraSharp.Simulation;
+
+namespace TerraSharp.Patches;
+
+// After the AI chose its velocity, before Projectile.Update moves it.
+internal static class ProjectilePatches
+{
+    delegate void Original(Projectile self);
+
+    internal static void Install(HookRegistry hooks) => hooks.Add(typeof(Projectile), nameof(Projectile.AI), (Action<Original, Projectile>)AI);
+
+    static void AI(Original original, Projectile self)
+    {
+        original(self);
+        if (Plugin.Active && Settings.MagicBullets && !Sandbox.Active && self.owner == Main.myPlayer)
+            Guard.Run("Projectile.AI postfix", MagicBullets.PostAI, self);
+    }
+}

src/TerraSharp/Simulation/Ballistics.cs

@@ -133,7 +133,7 @@ public static class Ballistics
             track.Age++;
 
             // Tile hits, bounces and homing turns show up as sharp changes.
-            if (!track.Spoiled && track.Velocities.Count > 0 && (velocity - track.LastVelocity).Length() > Math.Max(4f, track.LastVelocity.Length() * 0.5f))
+            if (!track.Spoiled && (MagicBullets.IsSteered(i) || (track.Velocities.Count > 0 && (velocity - track.LastVelocity).Length() > Math.Max(4f, track.LastVelocity.Length() * 0.5f))))
                 track.Spoiled = true;
             if (!track.Spoiled && track.Velocities.Count < MaxSamples)
                 track.Velocities.Add(velocity);

src/TerraSharp/UI/MainWindow.Pages.cs

@@ -101,6 +101,7 @@ public sealed partial class MainWindow
                 Slider("Max range", ref Settings.AimRange, 5f, 150f, 60f, "{0:0} tiles");
                 Toggle("Show target", ref Settings.AimDrawTarget);
             });
+        Toggle("Magic Bullets", ref Settings.MagicBullets);
         Toggle("Shot Preview", ref Settings.ShotPreview);
 
         Group("Enemies");

src/TerraSharp/UI/MainWindow.Tooltips.cs

@@ -28,6 +28,7 @@ public sealed partial class MainWindow
         ["Prediction"] = "Leads moving enemies and accounts for projectile drop.",
         ["Exact check"] = "Checks and corrects aim before firing. Auto Attack skips known misses. Orange brackets mean an unconfirmed shot.",
         ["Shot Preview"] = "Shows your next shot's path, including spread and homing.",
+        ["Magic Bullets"] = "Your projectiles home in on the aimbot target or the nearest enemy, through blocks.",
         ["Auto Attack"] = "Swings at enemies in reach and shoots at enemies your weapon can hit.",
         ["Show target"] = "Shows the cursor radius, target brackets and aim point.",
         ["Kill Aura"] = "Kills enemies in range and drops their loot.",

src/TerraSharp/UI/MainWindow.cs

@@ -32,7 +32,7 @@ public sealed partial class MainWindow : Window
         [
             new Page("Player", PlayerPage, () => Count(Settings.GodMode, Settings.InfHealth, Settings.InfMana, Settings.InfBreath, Settings.InfFlight, Settings.InstantRespawn, Settings.AutoHeal, Settings.AutoMana, Settings.GhostMode, Settings.DefenseBoost)),
             new Page("Movement", MovementPage, () => Count(Settings.Fly, Settings.SuperSpeed, Settings.HighJump, Settings.GravityFlip, Settings.NoFallDamage, Settings.LavaImmune, Settings.WaterWalk, Settings.NoKnockback, Settings.ExtendedReach)),
-            new Page("Combat", CombatPage, () => Count(Settings.RapidAttack, Settings.AutoSwing, Settings.DamageBoost, Settings.NoManaCost, Settings.NoSpread, Settings.Aimbot, Settings.AutoAttack, Settings.KillAura, Settings.HitMagnet, Settings.FreezeEnemies, Settings.WeakenEnemies)),
+            new Page("Combat", CombatPage, () => Count(Settings.RapidAttack, Settings.AutoSwing, Settings.DamageBoost, Settings.NoManaCost, Settings.NoSpread, Settings.Aimbot, Settings.AutoAttack, Settings.KillAura, Settings.HitMagnet, Settings.FreezeEnemies, Settings.WeakenEnemies, Settings.MagicBullets)),
             new Page("Items", ItemsPage, () => Count(Settings.InstantBreak, Settings.InfItems, Settings.ItemVacuum, Settings.AutoSell, Settings.AutoFish, Settings.Sonar)),
             new Page("Visuals", VisualsPage, () => Count(Settings.Esp, Settings.Spelunker, Settings.Hunter, Settings.Shine, Settings.NightOwl, Settings.DangerSense, Settings.BiomeSight, Settings.FullBright, Settings.ExtendedZoom)),
             new Page("World", WorldPage, () => Count(Settings.FreezeTime, Settings.SpawnRateBoost, Settings.MapTeleport)),