MADE: Fix movie audio glitches caused by reset of audio decoder

The sound buffer used in decompressSound() is now stored so that
it can be re-used in the next call of decompressSound, specifically
in chunk type 1.

This caused some clicking/static in the intro of Return to Zork.

Thanks to eriktorbjorn for noticing the glitch and writing most of the patch.

1 files changed, 16 insertions, 1 deletions

diff --git a/engines/made/sound.h b/engines/made/sound.h
index 6ffca13aaa..72537322f9 100644
--- a/engines/made/sound.h
+++ b/engines/made/sound.h
@@ -53,7 +53,22 @@ struct SoundEnergyItem {
 
 typedef Common::Array<SoundEnergyItem> SoundEnergyArray;
 
-void decompressSound(byte *source, byte *dest, uint16 chunkSize, uint16 chunkCount, SoundEnergyArray *soundEnergyArray = NULL);
+
+// Persistent data for decompressSound(). When calling decompressSound()
+// repeatedly (for the same stream), pass the same SoundDecoderData object to
+// ensure decoding properly resumes.
+class SoundDecoderData {
+public:
+	SoundDecoderData() {
+		memset(_soundBuffer, 0x80, sizeof(_soundBuffer));
+		_prevSample = 0;
+	}
+
+	byte _soundBuffer[1025];
+	int16 _prevSample;
+};
+
+void decompressSound(byte *source, byte *dest, uint16 chunkSize, uint16 chunkCount, SoundEnergyArray *soundEnergyArray = NULL, SoundDecoderData *decoderData = NULL);
 
 } // End of namespace Made