Merge pull request #138 from wyvernbw/master

Implement wrapper for SendLobbyChatMsg

src/matchmaking.rs

@@ -124,9 +124,7 @@ impl<Manager> Matchmaking<Manager> {
                 api_call,
                 CALLBACK_BASE_ID + 4,
                 move |v, io_error| {
-                    cb(if io_error {
-                        Err(())
-                    } else if v.m_EChatRoomEnterResponse != 1 {
+                    cb(if io_error || v.m_EChatRoomEnterResponse != 1 {
                         Err(())
                     } else {
                         Ok(LobbyId(v.m_ulSteamIDLobby))
@@ -271,6 +269,46 @@ impl<Manager> Matchmaking<Manager> {
     pub fn set_lobby_joinable(&self, lobby: LobbyId, joinable: bool) -> bool {
         unsafe { sys::SteamAPI_ISteamMatchmaking_SetLobbyJoinable(self.mm, lobby.0, joinable) }
     }
+
+    /// Broadcasts a chat message (text or binary data) to all users in the lobby.
+    ///
+    /// # Parameters
+    /// - `lobby`: The Steam ID of the lobby to send the chat message to.
+    /// - `msg`: This can be text or binary data, up to 4 Kilobytes in size.
+    ///
+    /// # Description
+    /// All users in the lobby (including the local user) will receive a `LobbyChatMsg_t` callback
+    /// with the message.
+    ///
+    /// If you're sending binary data, you should prefix a header to the message so that you know
+    /// to treat it as your custom data rather than a plain old text message.
+    ///
+    /// For communication that needs to be arbitrated (e.g., having a user pick from a set of characters),
+    /// you can use the lobby owner as the decision maker. `GetLobbyOwner` returns the current lobby owner.
+    /// There is guaranteed to always be one and only one lobby member who is the owner.
+    /// So for the choose-a-character scenario, the user who is picking a character would send the binary
+    /// message 'I want to be Zoe', the lobby owner would see that message, see if it was OK, and broadcast
+    /// the appropriate result (user X is Zoe).
+    ///
+    /// These messages are sent via the Steam back-end, and so the bandwidth available is limited.
+    /// For higher-volume traffic like voice or game data, you'll want to use the Steam Networking API.
+    ///
+    /// # Returns
+    /// Returns `Ok(())` if the message was successfully sent. Returns an error of type `SteamError` if the
+    /// message is too small or too large, or if no connection to Steam could be made.
+    pub fn send_lobby_chat_message(&self, lobby: LobbyId, msg: &[u8]) -> Result<(), SteamError> {
+        match unsafe {
+            steamworks_sys::SteamAPI_ISteamMatchmaking_SendLobbyChatMsg(
+                self.mm,
+                lobby.0,
+                msg.as_ptr() as *const c_void,
+                msg.len() as i32,
+            )
+        } {
+            true => Ok(()),
+            false => Err(SteamError::IOFailure),
+        }
+    }
 }
 
 /// Flags describing how a users lobby state has changed. This is provided from `LobbyChatUpdate`.