From b9681ccc26f6831702fe67cfb68e41aff77d8710 Mon Sep 17 00:00:00 2001
From: Karol Nowak <grzywacz@gmail.com>
Date: Sat, 17 Feb 2007 14:57:30 +0000
Subject: [PATCH] Possibly fixed a deadlock in sound code, removed warnings,
 improved comments.

---
 src/sound.cpp       | 8 ++++----
 src/soundsource.cpp | 7 +++++--
 src/soundsource.hpp | 5 +++--
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/sound.cpp b/src/sound.cpp
index bb3cb2ca348..f3324b1e5e4 100644
--- a/src/sound.cpp
+++ b/src/sound.cpp
@@ -589,8 +589,6 @@ void play_sound(const std::string& files, int channel)
 			}
 		}
 
-		threading::lock l(channel_mutex);
-
 		// the insertion will fail if there is already an element in the cache
 		std::pair< std::map< std::string, Mix_Chunk * >::iterator, bool >
 			it = sound_cache.insert(std::make_pair(file, (Mix_Chunk *)0));
@@ -622,12 +620,14 @@ void play_sound(const std::string& files, int channel)
 		//FIXME: in worst case it can play on bell channel(0), nothing happend
 		// only sound can have another volume than others sounds
 		const int res = Mix_PlayChannel(channel, cache, 0);
-		channel_chunks[res] = cache;
+
+		threading::lock l(channel_mutex);
 		if(res < 0) {
 			channel_chunks[res] = 0;
 			ERR_AUDIO << "error playing sound effect: " << Mix_GetError() << "\n";
 		}
-
+		else
+			channel_chunks[res] = cache;
 	}
 }
 
diff --git a/src/soundsource.cpp b/src/soundsource.cpp
index 236c484ba97..94e1581b7b3 100644
--- a/src/soundsource.cpp
+++ b/src/soundsource.cpp
@@ -29,7 +29,9 @@ int calculate_volume(int x, int y, const display &disp)
 	int dx = area.w / 2 - x; dx *= dx;
 	int dy = area.h / 2 - y; dy *= dy;
 
-	return maximum<int>(0, 256.0 * (sqrt(dx + dy) / (sqrt(area.w*area.w + area.h * area.h) / 2)));
+	// An obscure formula to calculate SDL_Mixer's "distance" based on the source's
+	// distance from screen's center
+	return maximum<int>(0, 128 * static_cast<int>(sqrt(dx + dy) / (sqrt(area.w*area.w + area.h * area.h))));
 }
 
 } // end of namespace
@@ -113,7 +115,8 @@ void manager::add_location(const std::string &name, const gamemap::location &loc
 
 manager::positional_source::positional_source(const std::string &files, int min_delay, int chance, bool play_fogged)
 						: _last_played(0), _min_delay(min_delay), _chance(chance), 
-							_play_fogged(play_fogged), _files(files), _id(last_id++)
+							_id(last_id++), _play_fogged(play_fogged), _visible(false),
+							_files(files)
 {
 }
 
diff --git a/src/soundsource.hpp b/src/soundsource.hpp
index 4eb2d03449c..f7908ad539f 100644
--- a/src/soundsource.hpp
+++ b/src/soundsource.hpp
@@ -48,10 +48,11 @@ class manager : public events::observer {
 
 	public:
 		// min_delay is a minimum time in seconds, which must pass before
-		// this sound source can be played again
+		// this sound source can be played again if it remains visible
 		//
 		// chance is a chance ;-) (in %) that the sound source will emit
-		// sound every second
+		// sound every second after the delay has passed or once the source
+		// becomes visible
 		positional_source(const std::string &files, int min_delay, int chance, bool play_fogged = false);
 
 		void update(unsigned int time, const display &disp);