SCI: some changes to the way reverb is handled

- "Invalid" SCI reverb values (127) are properly handled now
- SCI kDoSound(reverb) sets the global reverb (renamed it accordingly)
- kDoSound(reverb) can also return the current reverb if no parameter is sent

svn-id: r54457

1 files changed, 14 insertions, 2 deletions

diff --git a/engines/sci/sound/soundcmd.cpp b/engines/sci/sound/soundcmd.cpp
index d8cfa672ce..644e2a43d7 100644
--- a/engines/sci/sound/soundcmd.cpp
+++ b/engines/sci/sound/soundcmd.cpp
@@ -491,9 +491,21 @@ reg_t SoundCommandParser::kDoSoundSendMidi(int argc, reg_t *argv, reg_t acc) {
 	return acc;
 }
 
-reg_t SoundCommandParser::kDoSoundReverb(int argc, reg_t *argv, reg_t acc) {
-	debugC(2, kDebugLevelSound, "doSoundReverb: %d", argv[0].toUint16() & 0xF);
+reg_t SoundCommandParser::kDoSoundGlobalReverb(int argc, reg_t *argv, reg_t acc) {
+	if (argc == 0)
+		return make_reg(0, _music->getReverb());
+
+	debugC(2, kDebugLevelSound, "doSoundGlobalReverb: %d", argv[0].toUint16() & 0xF);
+
+	// This is a bit different than SSCI, but the end result should be the same.
+	// SSCI checks the first entry in the playlist for its current reverb value.
+	// If it's 127 (invalid), it sets the reverb parameter of this call to the
+	// driver, otherwise it doesn't, to preserve the song's reverb. When we modify
+	// the global reverb, we send its value to the soundcard, if it isn't 127 (invalid).
+	// This assumes that the currently set reverb in the driver will be the reverb
+	// value sent from the last song, which should be the one at the top of the list.
 	_music->setReverb(argv[0].toUint16() & 0xF);
+
 	return acc;
 }