WoW Area Triggers and Map Transitions

Overview

WoW has two kinds of locations that look like "entering a place":

Towns and castles (Stormwind, Ironforge, Stratholme) — these are WMO buildings embedded in the outdoor ADT map. The player walks into them; no map change occurs. They load automatically when the outdoor map loads.
Dungeons and instances (Deadmines, Shadowfang Keep, BRD) — these are separate maps stored as global-WMO WDT files (MPHD flag 0x01). A map change occurs when crossing a trigger portal in the outdoor world.

Map Types

All maps are in DBFilesClient\Map.dbc. The directory name in field 1 becomes the WDT path:

World/Maps/<dir>/<dir>.wdt

Dungeon maps use MPHD flag 0x01 in the WDT — the renderer detects this and suppresses terrain drawing, placing the single WMO directly from the WDT-level MODF chunk.

Loading a Map from the Command Line

# Load outdoor world by numeric ID (Map.dbc field 0)
make run-wow ARGS="+map 0"               # Eastern Kingdoms
make run-wow ARGS="+map 1"               # Kalimdor

# Load a dungeon directly by numeric ID (spawns at entrance position)
make run-wow ARGS="+map 36"              # Deadmines
make run-wow ARGS="+map 33"             # Shadowfang Keep

# Load outdoor world and warp to a named location (WorldSafeLocs or areatrigger)
make run-wow ARGS="+map 0 +warp stormwind"
make run-wow ARGS="+map 1 +warp crossroads"

+warp is a deferred client command — it fires after the player has connected and the map is loaded.

Note: These command combinations work regardless of which character race is set as default. If the default race has no playercreateinfo spawn on the target map, Wow_SpawnEntities falls back to any available spawn on that map and logs a warning; the +warp then repositions the player normally. See spawn-and-teleport.md for fallback details.

The `warp` Command

In-game usage: type warp <name> in the console.

Search order:

WorldSafeLocs on the current map — case-insensitive substring match. Returns the first entry whose name contains the query. Teleports player within the current map.
areatrigger_teleport data — case-insensitive substring match across all entries. If found, triggers a cross-map teleport (pending mechanism, same as area triggers).

Examples:

warp stormwind         → WorldSafeLoc "Stormwind City" (EK, same map)
warp ironforge         → WorldSafeLoc "Ironforge" (EK, same map)
warp deadmines         → areatrigger "DeadMines Entrance" → loads map 36
warp "scarlet monastery graveyard" → loads map 189

In-World Area Triggers (Dungeon Portals)

When a player walks through a dungeon entrance portal in the outdoor world, an area trigger fires automatically.

Data sources:

Source	Content	Local file
`AreaTrigger.dbc`	Trigger volumes (position, radius/box)	Read from MPQ at map load
`areatrigger_teleport.csv`	Destination (map, x, y, z, orientation)	`serverdata/areatrigger_teleport.csv` → `build/generated/g_areatrigger_teleport.c`

areatrigger_teleport.csv was extracted from AzerothCore's areatrigger_teleport SQL table (276 entries). It covers all classic WoW dungeon entrances and exits.

Lifecycle

Map A loads
  → Wow_SpawnEntities → Wow_LoadAreaTriggers
      reads AreaTrigger.dbc, caches entries for current map_id

Wow_RunFrame (every tick)
  → Wow_CheckAreaTriggers(player)
      for each trigger: sphere or OBB overlap test
      on hit: set wow_pending_teleport{x,y,z,orientation}
               gi.MenuAction("map", "World\\Maps\\Deadmines\\Deadmines.wdt")

Map B loads (Deadmines)
  → Wow_SpawnEntities
      sees wow_pending_teleport.pending == true
      uses pending x/y as spawn_origin
  → Wow_InitPlayer places player at (x, y, terrain_z)
  → post-init override: player->s.origin.z = pending.z  (SQL z is authoritative inside dungeons)
                         player->s.angle = pending.orientation
                         pending.pending = false
  → Wow_LoadAreaTriggers loads Deadmines exit triggers

Dungeon Spawn Position (Direct Load)

When a dungeon map is loaded directly (e.g. +map 36) without going through a trigger, Wow_SelectSpawnPoint returns ~0u because no playercreateinfo entry exists for dungeon map IDs. The code then:

Calls Wow_HasSpawnForMap(map_id) — returns false for dungeons (no race spawns there)
Falls back to Wow_AreaTrigSpawnForMap(map_id) — first areatrigger_teleport entry targeting this map
Sets the pending teleport mechanism with those coordinates

If no areatrigger entry targets this map, loading fails with an error log.

Key Implementation Points

Symbol	File	Purpose
`WOWAREATRIG`	`g_wow_local.h`	AreaTrigger.dbc record struct (10 fields, 40 bytes)
`WOWAREATRIGTELEPORT`	`g_wow_local.h`	areatrigger_teleport destination struct
`wow_pending_teleport`	`g_wow.c` (static)	Cross-map teleport state — cleared by Wow_SpawnEntities
`Wow_LoadAreaTriggers`	`g_wow.c`	Reads AreaTrigger.dbc for current map, filters by map_id
`Wow_CheckAreaTriggers`	`g_wow.c`	Per-frame player overlap test, fires map change on hit
`Wow_WdtPathForMapId`	`g_wow.c`	Builds WDT path from numeric Map.dbc ID
`Wow_HasSpawnForMap`	`g_playercreateinfo.c`	True if any race/class has playercreateinfo for this map
`Wow_AreaTrigSpawnForMap`	`g_areatrigger_teleport.c`	First entry targeting a given map_id
`Wow_AreaTrigTeleportByName`	`g_areatrigger_teleport.c`	Case-insensitive substring search by trigger name
`Wow_TeleportPlayerToPos`	`g_spawn.c`	Teleport to explicit x/y/z/orientation

AreaTrigger.dbc Field Layout (WoW 1.12)

10 fields, no string block, 40 bytes per record. Struct cast directly from the record:

Field	Type	Meaning
0	uint32	trigger id
1	uint32	map_id — map where the trigger exists
2–4	float	center x, y, z
5	float	radius (> 0 → sphere; == 0 → use box)
6–8	float	box half-extents x, y, z
9	float	box orientation (radians, rotates XY into local frame)

Caveats

Full portal-graph visibility culling is not yet implemented — all exterior WMO batches are suppressed when the camera is inside the WMO AABB, rather than per-portal. This is correct for correctness but may over-draw in large multi-room dungeons.
WMOAreaTable.dbc is not loaded — per-room ambient/fog/sound switching within a dungeon is not yet implemented.
MODD doodads that need a per-instance MOLT directional light (0x04 flag) are still skipped (TODO in r_wowmap_wmo.c).