ENGINES: Mute kPlainSoundType in Engine::syncSoundSettings()

The "Mute all" option rarely muted all audio streams, since we have
this abomination called kPlainSoundType (and there is no volume slider
for this type). Both, not-really-muting, and adding yet another slider is
a horrible user experience imho - especially on handheld ports.
So mute this sound in the default implementation, and unmute it to the
maximum volume.
When an engines has a volume level settings for sounds it plays with
this type, it should overwrite said member and set it there.

1 files changed, 9 insertions, 0 deletions

diff --git a/engines/engine.h b/engines/engine.h
index 508e9887ef..168a1dc2a0 100644
--- a/engines/engine.h
+++ b/engines/engine.h
@@ -163,6 +163,15 @@ public:
 	 * Notify the engine that the sound settings in the config manager may have
 	 * changed and that it hence should adjust any internal volume etc. values
 	 * accordingly.
+	 * The default implementation sets the volume levels of all mixer sound
+	 * types according to the config entries of the active domain.
+	 * When overwriting, call the default implementation first, then adjust the
+	 * volumes further (if required).
+	 *
+	 * @note When setting volume levels, respect the "mute" config entry.
+	 * @note The volume for the plain sound type is reset to the maximum
+	 *       volume. If the engine can associate its own value for this
+	 *       type, it needs to overwrite this member and set it accordingly.
 	 * @todo find a better name for this
 	 */
 	virtual void syncSoundSettings();