From 5957475d12c7739fbe69e569316a33588c621c51 Mon Sep 17 00:00:00 2001
From: Yohann Ferreira <yohann_dot_ferreira_at_orange_dot_efer>
Date: Mon, 11 Apr 2011 21:56:38 +0200
Subject: Implemented a simple non-blocking fadeOutAndPlay system.

It's currently used when changing maps.

Resolves: TMW-Mantis: #750.

Reviewed-by: Thorbjorn.
---
 src/client.cpp |  2 ++
 src/game.cpp   |  4 ++--
 src/sound.cpp  | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
 src/sound.h    | 28 +++++++++++++++++++++++++---
 4 files changed, 81 insertions(+), 12 deletions(-)

diff --git a/src/client.cpp b/src/client.cpp
index 2590813f..336abfbd 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -568,6 +568,8 @@ int Client::exec()
             if (game)
                 game->logic();
 
+            sound.logic();
+
             ++lastTickTime;
         }
 
diff --git a/src/game.cpp b/src/game.cpp
index 7f1def50..d2d2ecfd 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -982,9 +982,9 @@ void Game::changeMap(const std::string &mapPath)
     if (newMusic != oldMusic)
     {
         if (newMusic.empty())
-            sound.stopMusic();
+            sound.fadeOutMusic();
         else
-            sound.playMusic(newMusic);
+            sound.fadeOutAndPlayMusic(newMusic);
     }
 
     delete mCurrentMap;
diff --git a/src/sound.cpp b/src/sound.cpp
index c64e10d8..636da7c7 100644
--- a/src/sound.cpp
+++ b/src/sound.cpp
@@ -29,16 +29,37 @@
 #include "resources/resourcemanager.h"
 #include "resources/soundeffect.h"
 
+/**
+ * This will be set to true, when a music can be freed after a fade out
+ * Currently used by fadeOutCallBack()
+ */
+static bool sFadingOutEnded = false;
+
+/**
+ * Callback used at end of fadeout.
+ * It is called by Mix_MusicFadeFinished().
+ */
+static void fadeOutCallBack()
+{
+    sFadingOutEnded = true;
+}
+
 Sound::Sound():
     mInstalled(false),
     mSfxVolume(100),
     mMusicVolume(60),
     mMusic(NULL)
 {
+    // This set up our callback function used to
+    // handle fade outs endings.
+    sFadingOutEnded = false;
+    Mix_HookMusicFinished(fadeOutCallBack);
 }
 
 Sound::~Sound()
 {
+    // Unlink the callback function.
+    Mix_HookMusicFinished(NULL);
 }
 
 void Sound::init()
@@ -118,11 +139,6 @@ void Sound::info()
     logger->log("Sound::info() Channels: %i", channels);
 }
 
-int Sound::getMaxVolume() const
-{
-    return MIX_MAX_VOLUME;
-}
-
 void Sound::setMusicVolume(int volume)
 {
     mMusicVolume = volume;
@@ -223,8 +239,37 @@ void Sound::fadeOutMusic(int ms)
     if (mMusic)
     {
         Mix_FadeOutMusic(ms);
-        Mix_FreeMusic(mMusic);
-        mMusic = NULL;
+        // Note: The fadeOutCallBack handler will take care about freeing
+        // the music file at fade out ending.
+    }
+    else
+    {
+        sFadingOutEnded = true;
+    }
+}
+
+void Sound::fadeOutAndPlayMusic(const std::string &path, int ms)
+{
+    mNextMusicPath = path;
+    fadeOutMusic(ms);
+}
+
+void Sound::logic()
+{
+    if (sFadingOutEnded)
+    {
+        if (mMusic)
+        {
+            Mix_FreeMusic(mMusic);
+            mMusic = NULL;
+        }
+        sFadingOutEnded = false;
+
+        if (!mNextMusicPath.empty())
+        {
+            playMusic(mNextMusicPath);
+            mNextMusicPath.clear();
+        }
     }
 }
 
diff --git a/src/sound.h b/src/sound.h
index bfb3837b..1dee55e7 100644
--- a/src/sound.h
+++ b/src/sound.h
@@ -68,16 +68,25 @@ class Sound
          * @param path The full path to the music file.
          * @param ms   Duration of fade-in effect (ms)
          */
-        void fadeInMusic(const std::string &path, int ms = 2000);
+        void fadeInMusic(const std::string &path, int ms = 1000);
 
         /**
          * Fades out currently running background music track.
          *
          * @param ms   Duration of fade-out effect (ms)
          */
-        void fadeOutMusic(int ms);
+        void fadeOutMusic(int ms = 1000);
 
-        int getMaxVolume() const;
+        /**
+         * Fades out a background music and play a new one.
+         *
+         * @param path The full path to the fade in music file.
+         * @param ms   Duration of fade-out effect (ms)
+         */
+        void fadeOutAndPlayMusic(const std::string &path, int ms = 1000);
+
+        int getMaxVolume() const
+        { return MIX_MAX_VOLUME; }
 
         void setMusicVolume(int volume);
         void setSfxVolume(int volume);
@@ -91,6 +100,13 @@ class Sound
          */
         void playSfx(const std::string &path, int x = 0, int y = 0);
 
+        /**
+         * The sound logic.
+         * Currently used to check whether the music file can be freed after
+         * a fade out, and whether new music has to be played.
+         */
+        void logic();
+
     private:
         /** Logs various info about sound device. */
         void info();
@@ -98,6 +114,12 @@ class Sound
         /** Halts and frees currently playing music. */
         void haltMusic();
 
+        /**
+         * When calling fadeOutAndPlayMusic(),
+         * the music file below will then be played
+         */
+        std::string mNextMusicPath;
+
         bool mInstalled;
 
         int mSfxVolume;
-- 
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