MOHAWK: Always apply the volume when changing the background sound

3 files changed, 7 insertions, 12 deletions

diff --git a/engines/mohawk/myst_scripts.cpp b/engines/mohawk/myst_scripts.cpp
index 027a7fbf6c..a935ef5e5f 100644
--- a/engines/mohawk/myst_scripts.cpp
+++ b/engines/mohawk/myst_scripts.cpp
@@ -674,11 +674,6 @@ void MystScriptParser::o_copyImageToBackBuffer(uint16 op, uint16 var, uint16 arg
 	_vm->_gfx->copyImageSectionToBackBuffer(imageId, srcRect, dstRect);
 }
 
-// TODO: Though the playSound and PlaySoundBlocking opcodes play sounds immediately,
-//       this opcode changes the main background sound playing..
-//       Current behavior here and with VIEW sound block is not right as demonstrated
-//       by Channelwood Card 3280 (Tank Valve) and water flow sound behavior in pipe
-//       on cards leading from shed...
 void MystScriptParser::o_changeBackgroundSound(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
 	// Used on Stoneship Card 2080
 	// Used on Channelwood Card 3225 with argc = 8 i.e. Conditional Sound List
diff --git a/engines/mohawk/sound.cpp b/engines/mohawk/sound.cpp
index 198627e012..74796c3eda 100644
--- a/engines/mohawk/sound.cpp
+++ b/engines/mohawk/sound.cpp
@@ -625,7 +625,7 @@ uint16 Sound::convertMystID(uint16 id) {
 	return id;
 }
 
-Audio::SoundHandle *Sound::replaceBackgroundMyst(uint16 id, uint16 volume) {
+void Sound::replaceBackgroundMyst(uint16 id, uint16 volume) {
 	debug(0, "Replacing background sound with %d", id);
 
 	// TODO: The original engine does fading
@@ -641,8 +641,11 @@ Audio::SoundHandle *Sound::replaceBackgroundMyst(uint16 id, uint16 volume) {
 
 	// Check if sound is already playing
 	if (_mystBackgroundSound.type == kUsedHandle && _vm->_mixer->isSoundHandleActive(_mystBackgroundSound.handle)
-			&& _vm->getResourceName(ID_MSND, convertMystID(_mystBackgroundSound.id)).hasPrefix(prefix))
-		return &_mystBackgroundSound.handle;
+			&& _vm->getResourceName(ID_MSND, convertMystID(_mystBackgroundSound.id)).hasPrefix(prefix)) {
+		// The sound is already playing, just change the volume
+		changeBackgroundVolumeMyst(volume);
+		return;
+	}
 
 	// Stop old background sound
 	stopBackgroundMyst();
@@ -659,10 +662,7 @@ Audio::SoundHandle *Sound::replaceBackgroundMyst(uint16 id, uint16 volume) {
 		Audio::AudioStream *audStream = Audio::makeLoopingAudioStream(rewindStream, 0);
 
 		_vm->_mixer->playStream(Audio::Mixer::kPlainSoundType, &_mystBackgroundSound.handle, audStream, -1, volume >> 8);
-		return &_mystBackgroundSound.handle;
 	}
-
-	return NULL;
 }
 
 void Sound::stopBackgroundMyst() {
diff --git a/engines/mohawk/sound.h b/engines/mohawk/sound.h
index 75c9492d96..c62e6e9874 100644
--- a/engines/mohawk/sound.h
+++ b/engines/mohawk/sound.h
@@ -136,7 +136,7 @@ public:
 
 	// Myst-specific sound functions
 	Audio::SoundHandle *replaceSoundMyst(uint16 id, byte volume = Audio::Mixer::kMaxChannelVolume, bool loop = false);
-	Audio::SoundHandle *replaceBackgroundMyst(uint16 id, uint16 volume = 0xFFFF);
+	void replaceBackgroundMyst(uint16 id, uint16 volume = 0xFFFF);
 	void pauseBackgroundMyst();
 	void resumeBackgroundMyst();
 	void stopBackgroundMyst();