NPCSpawnHelper.cs

Go to the documentation of this file.

using System;
using System.Collections.Generic;
using Terraria.GameContent.Events;
using Terraria.ID;

namespace Terraria.ModLoader
{
    //todo: further documentation
    public static class NPCSpawnHelper
    {
        internal static List<SpawnCondition> conditions = new List<SpawnCondition>();

        internal static void Reset() {
            foreach (SpawnCondition cond in conditions) {
                cond.Reset();
            }
        }

        internal static void DoChecks(NPCSpawnInfo info) {
            float weight = 1f;
            foreach (SpawnCondition cond in conditions) {
                cond.Check(info, ref weight);
                if (Math.Abs(weight) < 5E-6) {
                    break;
                }
            }
        }
    }

    //todo: further documentation
    public class SpawnCondition
    {
        private Func<NPCSpawnInfo, bool> condition;
        private List<SpawnCondition> children;
        private float blockWeight;
        internal Func<float> WeightFunc;

        private float chance;
        private bool active;

        internal IEnumerable<SpawnCondition> Children => children;
        internal float BlockWeight => blockWeight;

        public float Chance => chance;
        public bool Active => active;

        internal SpawnCondition(Func<NPCSpawnInfo, bool> condition, float blockWeight = 1f) {
            this.condition = condition;
            this.children = new List<SpawnCondition>();
            this.blockWeight = blockWeight;
            NPCSpawnHelper.conditions.Add(this);
        }

        internal SpawnCondition(SpawnCondition parent, Func<NPCSpawnInfo, bool> condition, float blockWeight = 1f) {
            this.condition = condition;
            this.children = new List<SpawnCondition>();
            this.blockWeight = blockWeight;
            parent.children.Add(this);
        }

        internal void Reset() {
            chance = 0f;
            active = false;
            foreach (SpawnCondition child in children) {
                child.Reset();
            }
        }

        internal void Check(NPCSpawnInfo info, ref float remainingWeight) {
            if (WeightFunc != null) {
                blockWeight = WeightFunc();
            }
            active = true;
            if (condition(info)) {
                chance = remainingWeight * blockWeight;
                float childWeight = chance;
                foreach (SpawnCondition child in children) {
                    child.Check(info, ref childWeight);
                    if (Math.Abs(childWeight) < 5E-6) {
                        break;
                    }
                }
                remainingWeight -= chance;
            }
        }

        public static readonly SpawnCondition NebulaTower;
        public static readonly SpawnCondition VortexTower;
        public static readonly SpawnCondition StardustTower;
        public static readonly SpawnCondition SolarTower;
        public static readonly SpawnCondition Sky;
        public static readonly SpawnCondition Invasion;
        public static readonly SpawnCondition GoblinArmy;
        public static readonly SpawnCondition FrostLegion;
        public static readonly SpawnCondition Pirates;
        public static readonly SpawnCondition MartianMadness;
        public static readonly SpawnCondition Bartender;
        public static readonly SpawnCondition SpiderCave;
        public static readonly SpawnCondition DesertCave;
        public static readonly SpawnCondition HardmodeJungleWater;
        public static readonly SpawnCondition HardmodeCrimsonWater;
        public static readonly SpawnCondition Ocean;
        public static readonly SpawnCondition OceanAngler;
        public static readonly SpawnCondition OceanMonster;
        public static readonly SpawnCondition BeachAngler;
        public static readonly SpawnCondition JungleWater;
        public static readonly SpawnCondition CavePiranha;
        public static readonly SpawnCondition CaveJellyfish;
        public static readonly SpawnCondition WaterCritter;
        public static readonly SpawnCondition CorruptWaterCritter;
        public static readonly SpawnCondition OverworldWaterCritter;
        public static readonly SpawnCondition OverworldWaterSurfaceCritter;
        public static readonly SpawnCondition OverworldUnderwaterCritter;
        public static readonly SpawnCondition DefaultWaterCritter;
        public static readonly SpawnCondition BoundCaveNPC;
        public static readonly SpawnCondition TownCritter;
        public static readonly SpawnCondition TownWaterCritter;
        public static readonly SpawnCondition TownOverworldWaterCritter;
        public static readonly SpawnCondition TownOverworldWaterSurfaceCritter;
        public static readonly SpawnCondition TownOverworldUnderwaterCritter;
        public static readonly SpawnCondition TownDefaultWaterCritter;
        public static readonly SpawnCondition TownSnowCritter;
        public static readonly SpawnCondition TownJungleCritter;
        public static readonly SpawnCondition TownGeneralCritter;
        public static readonly SpawnCondition Dungeon;
        public static readonly SpawnCondition DungeonGuardian;
        public static readonly SpawnCondition DungeonNormal;
        public static readonly SpawnCondition Meteor;
        public static readonly SpawnCondition OldOnesArmy;
        public static readonly SpawnCondition FrostMoon;
        public static readonly SpawnCondition PumpkinMoon;
        public static readonly SpawnCondition SolarEclipse;
        public static readonly SpawnCondition HardmodeMushroomWater;
        public static readonly SpawnCondition OverworldMushroom;
        public static readonly SpawnCondition UndergroundMushroom;
        public static readonly SpawnCondition CorruptWorm;
        public static readonly SpawnCondition UndergroundMimic;
        public static readonly SpawnCondition OverworldMimic;
        public static readonly SpawnCondition Wraith;
        public static readonly SpawnCondition HoppinJack;
        public static readonly SpawnCondition DoctorBones;
        public static readonly SpawnCondition LacBeetle;
        public static readonly SpawnCondition WormCritter;
        public static readonly SpawnCondition MouseCritter;
        public static readonly SpawnCondition SnailCritter;
        public static readonly SpawnCondition FrogCritter;
        public static readonly SpawnCondition HardmodeJungle;
        public static readonly SpawnCondition JungleTemple;
        public static readonly SpawnCondition UndergroundJungle;
        public static readonly SpawnCondition SurfaceJungle;
        public static readonly SpawnCondition SandstormEvent;
        public static readonly SpawnCondition Mummy;
        public static readonly SpawnCondition DarkMummy;
        public static readonly SpawnCondition LightMummy;
        public static readonly SpawnCondition OverworldHallow;
        public static readonly SpawnCondition EnchantedSword;
        public static readonly SpawnCondition Crimson;
        public static readonly SpawnCondition Corruption;
        public static readonly SpawnCondition Overworld;
        public static readonly SpawnCondition IceGolem;
        public static readonly SpawnCondition RainbowSlime;
        public static readonly SpawnCondition AngryNimbus;
        public static readonly SpawnCondition MartianProbe;
        public static readonly SpawnCondition OverworldDay;
        public static readonly SpawnCondition OverworldDaySnowCritter;
        public static readonly SpawnCondition OverworldDayGrassCritter;
        public static readonly SpawnCondition OverworldDaySandCritter;
        public static readonly SpawnCondition OverworldMorningBirdCritter;
        public static readonly SpawnCondition OverworldDayBirdCritter;
        public static readonly SpawnCondition KingSlime;
        public static readonly SpawnCondition OverworldDayDesert;
        public static readonly SpawnCondition GoblinScout;
        public static readonly SpawnCondition OverworldDayRain;
        public static readonly SpawnCondition OverworldDaySlime;
        public static readonly SpawnCondition OverworldNight;
        public static readonly SpawnCondition OverworldFirefly;
        public static readonly SpawnCondition OverworldNightMonster;
        public static readonly SpawnCondition Underground;
        public static readonly SpawnCondition Underworld;
        public static readonly SpawnCondition Cavern;

        static SpawnCondition() {
            NebulaTower = new SpawnCondition((info) => info.player.ZoneTowerNebula);
            VortexTower = new SpawnCondition((info) => info.player.ZoneTowerVortex);
            StardustTower = new SpawnCondition((info) => info.player.ZoneTowerStardust);
            SolarTower = new SpawnCondition((info) => info.player.ZoneTowerSolar);
            Sky = new SpawnCondition((info) => info.sky);
            Invasion = new SpawnCondition((info) => info.invasion);
            GoblinArmy = new SpawnCondition(Invasion, (info) => Main.invasionType == 1);
            FrostLegion = new SpawnCondition(Invasion, (info) => Main.invasionType == 2);
            Pirates = new SpawnCondition(Invasion, (info) => Main.invasionType == 3);
            MartianMadness = new SpawnCondition(Invasion, (info) => Main.invasionType == 4);
            Bartender = new SpawnCondition((info) => !NPC.savedBartender && DD2Event.ReadyToFindBartender
                && !NPC.AnyNPCs(NPCID.BartenderUnconscious) && !info.water, 1f / 80f);
            SpiderCave = new SpawnCondition((info) => GetTile(info).wall == WallID.SpiderUnsafe || info.spiderCave);
            DesertCave = new SpawnCondition((info) => (WallID.Sets.Conversion.HardenedSand[GetTile(info).wall]
                || WallID.Sets.Conversion.Sandstone[GetTile(info).wall] || info.desertCave)
                && WorldGen.checkUnderground(info.spawnTileX, info.spawnTileY));
            HardmodeJungleWater = new SpawnCondition((info) => Main.hardMode && info.water && info.player.ZoneJungle, 2f / 3f);
            HardmodeCrimsonWater = new SpawnCondition((info) => Main.hardMode && info.water && info.player.ZoneCrimson, 8f / 9f);
            Ocean = new SpawnCondition((info) => info.water && (info.spawnTileX < 250 || info.spawnTileX > Main.maxTilesX - 250)
                && Main.tileSand[info.spawnTileType] && info.spawnTileY < Main.rockLayer);
            OceanAngler = new SpawnCondition(Ocean, (info) => !NPC.savedAngler && !NPC.AnyNPCs(NPCID.SleepingAngler)
                && WaterSurface(info));
            OceanMonster = new SpawnCondition(Ocean, (info) => true);
            BeachAngler = new SpawnCondition((info) => !info.water && !NPC.savedAngler && !NPC.AnyNPCs(NPCID.SleepingAngler)
                && (info.spawnTileX < 340 || info.spawnTileX > Main.maxTilesX - 340) && Main.tileSand[info.spawnTileType]
                && info.spawnTileY < Main.worldSurface);
            JungleWater = new SpawnCondition((info) => info.water && info.spawnTileType == TileID.JungleGrass);
            CavePiranha = new SpawnCondition((info) => info.water && info.spawnTileY > Main.rockLayer, 0.5f);
            CaveJellyfish = new SpawnCondition((info) => info.water && info.spawnTileY > Main.worldSurface, 1f / 3f);
            WaterCritter = new SpawnCondition((info) => info.water, 0.25f);
            CorruptWaterCritter = new SpawnCondition(WaterCritter, (info) => info.player.ZoneCorrupt);
            OverworldWaterCritter = new SpawnCondition(WaterCritter, (info) => info.spawnTileY < Main.worldSurface
                && info.spawnTileY > 50 && Main.dayTime, 2f / 3f);
            OverworldWaterSurfaceCritter = new SpawnCondition(OverworldWaterCritter, WaterSurface);
            OverworldUnderwaterCritter = new SpawnCondition(OverworldWaterCritter, (info) => true);
            DefaultWaterCritter = new SpawnCondition(WaterCritter, (info) => true);
            BoundCaveNPC = new SpawnCondition((info) => !info.water && info.spawnTileY >= Main.rockLayer
                && info.spawnTileY < Main.maxTilesY - 210, 1f / 20f);
            TownCritter = new SpawnCondition((info) => info.playerInTown);
            TownWaterCritter = new SpawnCondition(TownCritter, (info) => info.water);
            TownOverworldWaterCritter = new SpawnCondition(TownWaterCritter, (info) => info.spawnTileY < Main.worldSurface
                && info.spawnTileY > 50 && Main.dayTime, 2f / 3f);
            TownOverworldWaterSurfaceCritter = new SpawnCondition(TownOverworldWaterCritter, WaterSurface);
            TownOverworldUnderwaterCritter = new SpawnCondition(TownOverworldWaterCritter, (info) => true);
            TownDefaultWaterCritter = new SpawnCondition(TownWaterCritter, (info) => true);
            TownSnowCritter = new SpawnCondition(TownCritter, (info) => info.spawnTileType == TileID.SnowBlock
                || info.spawnTileType == TileID.IceBlock);
            TownJungleCritter = new SpawnCondition(TownCritter, (info) => info.spawnTileType == TileID.JungleGrass);
            TownGeneralCritter = new SpawnCondition(TownCritter, (info) => info.spawnTileType == TileID.Grass
                || info.spawnTileType == TileID.HallowedGrass || info.spawnTileY > Main.worldSurface);
            Dungeon = new SpawnCondition((info) => info.player.ZoneDungeon);
            DungeonGuardian = new SpawnCondition(Dungeon, (info) => !NPC.downedBoss3);
            DungeonNormal = new SpawnCondition(Dungeon, (info) => true);
            Meteor = new SpawnCondition((info) => info.player.ZoneMeteor);
            OldOnesArmy = new SpawnCondition((info) => DD2Event.Ongoing && info.player.ZoneOldOneArmy);
            FrostMoon = new SpawnCondition((info) => info.spawnTileY <= Main.worldSurface && !Main.dayTime && Main.snowMoon);
            PumpkinMoon = new SpawnCondition((info) => info.spawnTileY <= Main.worldSurface
                && !Main.dayTime && Main.pumpkinMoon);
            SolarEclipse = new SpawnCondition((info) => info.spawnTileY <= Main.worldSurface && Main.dayTime && Main.eclipse);
            HardmodeMushroomWater = new SpawnCondition((info) => Main.hardMode && info.spawnTileType == TileID.MushroomGrass
                && info.water);
            OverworldMushroom = new SpawnCondition((info) => info.spawnTileType == TileID.MushroomGrass
                && info.spawnTileY <= Main.worldSurface, 2f / 3f);
            UndergroundMushroom = new SpawnCondition((info) => info.spawnTileType == TileID.MushroomGrass
                && Main.hardMode && info.spawnTileY >= Main.worldSurface, 2f / 3f);
            CorruptWorm = new SpawnCondition((info) => info.player.ZoneCorrupt && !info.playerSafe, 1f / 65f);
            UndergroundMimic = new SpawnCondition((info) => Main.hardMode && info.spawnTileY > Main.worldSurface, 1f / 70f);
            OverworldMimic = new SpawnCondition((info) => Main.hardMode && GetTile(info).wall == WallID.DirtUnsafe, 0.05f);
            Wraith = new SpawnCondition((info) => Main.hardMode && info.spawnTileY <= Main.worldSurface
                && !Main.dayTime, 0.05f);
            Wraith.WeightFunc = () => {
                float inverseChance = 0.95f;
                if (Main.moonPhase == 4) {
                    inverseChance *= 0.8f;
                }
                return 1f - inverseChance;
            };
            HoppinJack = new SpawnCondition((info) => Main.hardMode && Main.halloween
                && info.spawnTileY <= Main.worldSurface && !Main.dayTime, 0.1f);
            DoctorBones = new SpawnCondition((info) => info.spawnTileType == TileID.JungleGrass && !Main.dayTime, 0.002f);
            LacBeetle = new SpawnCondition((info) => info.spawnTileType == TileID.JungleGrass
                && info.spawnTileY > Main.worldSurface, 1f / 60f);
            WormCritter = new SpawnCondition((info) => info.spawnTileY > Main.worldSurface
                && info.spawnTileY < Main.maxTilesY - 210 && !info.player.ZoneSnow && !info.player.ZoneCrimson
                && !info.player.ZoneCorrupt && !info.player.ZoneJungle && !info.player.ZoneHoly, 1f / 8f);
            MouseCritter = new SpawnCondition((info) => info.spawnTileY > Main.worldSurface
                && info.spawnTileY < Main.maxTilesY - 210 && !info.player.ZoneSnow && !info.player.ZoneCrimson
                && !info.player.ZoneCorrupt && !info.player.ZoneJungle && !info.player.ZoneHoly, 1f / 13f);
            SnailCritter = new SpawnCondition((info) => info.spawnTileY > Main.worldSurface
                && info.spawnTileY < (Main.rockLayer + Main.maxTilesY) / 2 && !info.player.ZoneSnow
                && !info.player.ZoneCrimson && !info.player.ZoneCorrupt && !info.player.ZoneHoly, 1f / 13f);
            FrogCritter = new SpawnCondition((info) => info.spawnTileY < Main.worldSurface && info.player.ZoneJungle, 1f / 9f);
            HardmodeJungle = new SpawnCondition((info) => info.spawnTileType == TileID.JungleGrass && Main.hardMode, 2f / 3f);
            JungleTemple = new SpawnCondition((info) => info.spawnTileType == TileID.LihzahrdBrick && info.lihzahrd);
            UndergroundJungle = new SpawnCondition((info) => info.spawnTileType == TileID.JungleGrass
                && info.spawnTileY > (Main.worldSurface + Main.rockLayer) / 2);
            SurfaceJungle = new SpawnCondition((info) => info.spawnTileType == TileID.JungleGrass, 11f / 32f);
            SandstormEvent = new SpawnCondition((info) => Sandstorm.Happening && info.player.ZoneSandstorm
                && TileID.Sets.Conversion.Sand[info.spawnTileType]
                && NPC.Spawning_SandstoneCheck(info.spawnTileX, info.spawnTileY));
            Mummy = new SpawnCondition((info) => Main.hardMode && info.spawnTileType == TileID.Sand, 1f / 3f);
            DarkMummy = new SpawnCondition((info) => Main.hardMode && (info.spawnTileType == TileID.Ebonsand
                || info.spawnTileType == TileID.Crimsand), 0.5f);
            LightMummy = new SpawnCondition((info) => Main.hardMode && info.spawnTileType == TileID.Pearlsand, 0.5f);
            OverworldHallow = new SpawnCondition((info) => Main.hardMode && !info.water && info.spawnTileY < Main.rockLayer
                && (info.spawnTileType == TileID.Pearlsand || info.spawnTileType == TileID.Pearlstone
                || info.spawnTileType == TileID.HallowedGrass || info.spawnTileType == TileID.HallowedIce));
            EnchantedSword = new SpawnCondition((info) => !info.playerSafe && Main.hardMode && !info.water
                && info.spawnTileY >= Main.rockLayer && (info.spawnTileType == TileID.Pearlsand
                || info.spawnTileType == TileID.Pearlstone || info.spawnTileType == TileID.HallowedGrass
                || info.spawnTileType == TileID.HallowedIce), 0.02f);
            Crimson = new SpawnCondition((info) => (info.spawnTileType == TileID.Crimtane && info.player.ZoneCrimson)
                || info.spawnTileType == TileID.FleshGrass || info.spawnTileType == TileID.FleshIce
                || info.spawnTileType == TileID.Crimstone || info.spawnTileType == TileID.Crimsand);
            Corruption = new SpawnCondition((info) => (info.spawnTileType == TileID.Demonite && info.player.ZoneCorrupt)
                || info.spawnTileType == TileID.CorruptGrass || info.spawnTileType == TileID.Ebonstone
                || info.spawnTileType == TileID.Ebonsand || info.spawnTileType == TileID.CorruptIce);
            Overworld = new SpawnCondition((info) => info.spawnTileY <= Main.worldSurface);
            IceGolem = new SpawnCondition(Overworld, (info) => info.player.ZoneSnow && Main.hardMode
                && Main.cloudAlpha > 0f && !NPC.AnyNPCs(NPCID.IceGolem), 0.05f);
            RainbowSlime = new SpawnCondition(Overworld, (info) => info.player.ZoneHoly && Main.hardMode
                && Main.cloudAlpha > 0f && !NPC.AnyNPCs(NPCID.RainbowSlime), 0.05f);
            AngryNimbus = new SpawnCondition(Overworld, (info) => !info.player.ZoneSnow && Main.hardMode
                && Main.cloudAlpha > 0f && NPC.CountNPCS(NPCID.AngryNimbus) < 2, 0.1f);
            MartianProbe = new SpawnCondition(Overworld, (info) => MartianProbeHelper(info) && Main.hardMode
                && NPC.downedGolemBoss && !NPC.AnyNPCs(NPCID.MartianProbe), 1f / 400f);
            MartianProbe.WeightFunc = () => {
                float inverseChance = 399f / 400f;
                if (!NPC.downedMartians) {
                    inverseChance *= 0.99f;
                }
                return 1f - inverseChance;
            };
            OverworldDay = new SpawnCondition(Overworld, (info) => Main.dayTime);
            OverworldDaySnowCritter = new SpawnCondition(OverworldDay, (info) => InnerThird(info)
                && (GetTile(info).type == TileID.SnowBlock || GetTile(info).type == TileID.IceBlock), 1f / 15f);
            OverworldDayGrassCritter = new SpawnCondition(OverworldDay, (info) => InnerThird(info)
                && (GetTile(info).type == TileID.Grass || GetTile(info).type == TileID.HallowedGrass), 1f / 15f);
            OverworldDaySandCritter = new SpawnCondition(OverworldDay, (info) => InnerThird(info)
                && GetTile(info).type == TileID.Sand, 1f / 15f);
            OverworldMorningBirdCritter = new SpawnCondition(OverworldDay, (info) => InnerThird(info) && Main.time < 18000.0
            && (GetTile(info).type == TileID.Grass || GetTile(info).type == TileID.HallowedGrass), 0.25f);
            OverworldDayBirdCritter = new SpawnCondition(OverworldDay, (info) => InnerThird(info)
                && (GetTile(info).type == TileID.Grass || GetTile(info).type == TileID.HallowedGrass
                || GetTile(info).type == TileID.SnowBlock), 1f / 15f);
            KingSlime = new SpawnCondition(OverworldDay, (info) => OuterThird(info) && GetTile(info).type == TileID.Grass
                && !NPC.AnyNPCs(NPCID.KingSlime), 1f / 300f);
            OverworldDayDesert = new SpawnCondition(OverworldDay, (info) => GetTile(info).type == TileID.Sand
                && !info.water, 0.2f);
            GoblinScout = new SpawnCondition(OverworldDay, (info) => OuterThird(info), 1f / 15f);
            GoblinScout.WeightFunc = () => {
                float inverseChance = 14f / 15f;
                if (!NPC.downedGoblins && WorldGen.shadowOrbSmashed) {
                    return inverseChance *= (6f / 7f);
                }
                return 1f - inverseChance;
            };
            OverworldDayRain = new SpawnCondition(OverworldDay, (info) => Main.raining, 2f / 3f);
            OverworldDaySlime = new SpawnCondition(OverworldDay, (info) => true);
            OverworldNight = new SpawnCondition(Overworld, (info) => true);
            OverworldFirefly = new SpawnCondition(OverworldNight, (info) => GetTile(info).type == TileID.Grass
                || GetTile(info).type == TileID.HallowedGrass, 0.1f);
            OverworldFirefly.WeightFunc = () => 1f / (float)NPC.fireFlyChance;
            OverworldNightMonster = new SpawnCondition(OverworldNight, (info) => true);
            Underground = new SpawnCondition((info) => info.spawnTileY <= Main.rockLayer);
            Underworld = new SpawnCondition((info) => info.spawnTileY > Main.maxTilesY - 190);
            Cavern = new SpawnCondition((info) => true);
        }

        private static Tile GetTile(NPCSpawnInfo info) {
            return Main.tile[info.spawnTileX, info.spawnTileY];
        }

        private static bool WaterSurface(NPCSpawnInfo info) {
            if (info.safeRangeX) {
                return false;
            }
            for (int k = info.spawnTileY - 1; k > info.spawnTileY - 50; k--) {
                if (Main.tile[info.spawnTileX, k].liquid == 0 && !WorldGen.SolidTile(info.spawnTileX, k)
                    && !WorldGen.SolidTile(info.spawnTileX, k + 1) && !WorldGen.SolidTile(info.spawnTileX, k + 2)) {
                    return true;
                }
            }
            return false;
        }

        private static bool MartianProbeHelper(NPCSpawnInfo info) {
            return (float)Math.Abs(info.spawnTileX - Main.maxTilesX / 2) / (float)(Main.maxTilesX / 2) > 0.33f
                && !NPC.AnyDanger();
        }

        private static bool InnerThird(NPCSpawnInfo info) {
            return Math.Abs(info.spawnTileX - Main.spawnTileX) < Main.maxTilesX / 3;
        }

        private static bool OuterThird(NPCSpawnInfo info) {
            return Math.Abs(info.spawnTileX - Main.spawnTileX) > Main.maxTilesX / 3;
        }
    }
}