From Guild Wars 2 Wiki
Jump to navigationJump to search

GuildWars 2 is exposing a number of real-time contextual data using the MumbleLink specification.

This allows desktop developers to obtain information about the player state without having to query the API

MumbleLink structure

The MumbleLink specification is a Memory Shared File named "MumbleLink" using the following structure:[1]

struct LinkedMem {
    uint32_t uiVersion;
    uint32_t uiTick;
    float fAvatarPosition[3];
    float fAvatarFront[3];
    float fAvatarTop[3];
    wchar_t name[256];
    float fCameraPosition[3];
    float fCameraFront[3];
    float fCameraTop[3];
    wchar_t identity[256];
    uint32_t context_len; // Despite the actual context containing more data, this value is currently 48. See "context" section below.
    unsigned char context[256];
    wchar_t description[2048];

Value updates

  • The fAvatar* variables appear to be updated 25 times per second.
  • The fCamera* variables appear to be updated every frame.
  • identity appears to be updated every frame.
  • context appears to be updated every frame.
  • It would appear likely that everything (except the fAvatar* vars) is updated every frame, though this is difficult to determine for some variables as while they may be updated at said frequency the frequency can't be inferred by observing a variable's value if the value can't be changed as frequent or more frequently than the frame rate.


fAvatarPosition is the position of the player in the coordinate system of the map. While the game uses inches as unit, mumble uses meters. To use them like other coordinates in the game, they have to be converted to inches first. API:1/event details#Coordinate recalculation describes the games coordinate systems in detail.

The context field contains further information needed to process the position, as well as the position in the continent coordinate system.

Usage in Guild Wars 2

In addition to the f* vars, Guild Wars 2 utilizes the context and identity fields to store additional data.


The context field holds another structure containing the following data.[2]

Note: Mumble only uses the first context_len bytes of the data below to determine whether people are on the same server shard or not.

struct MumbleContext {
    unsigned char serverAddress[28]; // contains sockaddr_in or sockaddr_in6
    uint32_t mapId;
    uint32_t mapType;
    uint32_t shardId;
    uint32_t instance;
    uint32_t buildId;
    // Additional data beyond the <context_len> bytes the game instructs Mumble to use to distinguish between instances.
    uint32_t uiState; // Bitmask: Bit 1 = IsMapOpen, Bit 2 = IsCompassTopRight, Bit 3 = DoesCompassHaveRotationEnabled, Bit 4 = Game has focus, Bit 5 = Is in Competitive game mode, Bit 6 = Textbox has focus, Bit 7 = Is in Combat
    uint16_t compassWidth; // pixels
    uint16_t compassHeight; // pixels
    float compassRotation; // radians
    float playerX; // continentCoords
    float playerY; // continentCoords
    float mapCenterX; // continentCoords
    float mapCenterY; // continentCoords
    float mapScale;
    uint32_t processId;
    uint8_t mountIndex;


The identity field contains a JSON string with the following fields.[4]


  "name": "Irwene",
  "profession": 4,
  "spec": 55,
  "race": 4,
  "map_id": 50,
  "world_id": 268435505,
  "team_color_id": 0,
  "commander": false,
  "fov": 0.873,
  "uisz": 1


  1. ^ Mumble Wiki
  2. ^ This was discovered by various forum users and confirmed by Arena Net Staff [1]
  3. ^ https://github.com/arenanet/api-cdi/blob/master/mumble.md
  4. ^ The meaning of some numerical values were found by users on the Guild Wars 2 API development forums [2]


The value exposed by world_id was not updated following the introduction of the megaserver system, and currently shows the same value as the shardId that can be found in the context field. (ref)

See also