TITANIC: FIxes and cleanup for instrument mixer code

4 files changed, 14 insertions, 11 deletions

diff --git a/engines/titanic/sound/music_wave.cpp b/engines/titanic/sound/music_wave.cpp
index 8f3f3005ba..11458642df 100644
--- a/engines/titanic/sound/music_wave.cpp
+++ b/engines/titanic/sound/music_wave.cpp
@@ -277,20 +277,22 @@ int CMusicWave::read(uint16 *ptr, uint size) {
 		size = _size;
 
 	if (_waveIndex != -1) {
-		const byte *data = _items[_waveIndex]._waveFile->lock();
+		// Lock the specified wave file for access
+		const uint16 *data = _items[_waveIndex]._waveFile->lock();
 		assert(data);
-		const uint16 *src = (const uint16 *)data;
+		const uint16 *src = data;
 
-		// Loop through copying over data
-		for (uint idx = 0; idx < size; idx += 2, _readPos += _readIncrement) {
+		// Loop through merging data from the wave file into the dest buffer
+		for (uint idx = 0; idx < (size / sizeof(uint16)); ++idx, _readPos += _readIncrement) {
 			uint srcPos = _readPos >> 8;
 			if (srcPos >= _count)
 				break;
 
 			uint16 val = READ_LE_UINT16(src + srcPos);
-			*ptr++ = val;
+			*ptr++ += val;
 		}
 
+		// Unlock the wave file
 		_items[_waveIndex]._waveFile->unlock(data);
 	}
 
diff --git a/engines/titanic/sound/music_wave.h b/engines/titanic/sound/music_wave.h
index 5b63c74f7f..5d205259ee 100644
--- a/engines/titanic/sound/music_wave.h
+++ b/engines/titanic/sound/music_wave.h
@@ -117,7 +117,8 @@ public:
 	void setSize(uint total);
 
 	/**
-	 * Reads sound data and passes it to the provided buffer
+	 * If there is any wave file currently specified, reads it in
+	 * and merges it into the supplied buffer
 	 */
 	int read(uint16 *ptr, uint size);
 
diff --git a/engines/titanic/sound/wave_file.cpp b/engines/titanic/sound/wave_file.cpp
index a328fe1543..0d9d86d714 100644
--- a/engines/titanic/sound/wave_file.cpp
+++ b/engines/titanic/sound/wave_file.cpp
@@ -165,18 +165,18 @@ void CWaveFile::reset() {
 	audioStream()->rewind();
 }
 
-const byte *CWaveFile::lock() {
+const uint16 *CWaveFile::lock() {
 	switch (_loadMode) {
 	case LOADMODE_SCUMMVM:
 		assert(_waveData);
-		return _waveData + _headerSize;
+		return (uint16 *)(_waveData + _headerSize);
 
 	default:
 		return nullptr;
 	}
 }
 
-void CWaveFile::unlock(const byte *ptr) {
+void CWaveFile::unlock(const uint16 *ptr) {
 	// No implementation needed in ScummVM
 }
 
diff --git a/engines/titanic/sound/wave_file.h b/engines/titanic/sound/wave_file.h
index f37557c7a8..5a467c8fd5 100644
--- a/engines/titanic/sound/wave_file.h
+++ b/engines/titanic/sound/wave_file.h
@@ -125,12 +125,12 @@ public:
 	/**
 	 * Lock sound data for access
 	 */
-	const byte *lock();
+	const uint16 *lock();
 
 	/**
 	 * Unlock sound data after a prior call to lock
 	 */
-	void unlock(const byte *ptr);
+	void unlock(const uint16 *ptr);
 };
 
 } // End of namespace Titanic