SOUND: Load XACT SoundBank mix bins event parameters

src/sound/xactsoundbank.cpp

@@ -129,6 +129,13 @@ XACTSoundBank::Event::Event(EventType t) : type(t), timestamp(0) {
 			params.marker.value = 0;
 			break;
 
+		case kEventTypeMixBins:
+			for (size_t i = 0; i < ARRAYSIZE(params.mixbins.bins); i++) {
+				params.mixbins.bins[i].channel = 0;
+				params.mixbins.bins[i].volume  = -64.0f;
+			}
+			break;
+
 		default:
 			break;
 	}

src/sound/xactsoundbank.h

@@ -270,6 +270,13 @@ class XACTSoundBank {
 				uint32 value; ///< Custom, user-set value of the marker.
 			} marker;
 
+			struct {
+				struct {
+					uint8 channel; ///< Index of the channel to set the volume of.
+					float volume;  ///< Attenuation in dB (-64.0f to 0.0f).
+				} bins[8];
+			} mixbins;
+
 		} params;
 
 		Event(EventType t);

src/sound/xactsoundbank_binary.cpp

@@ -412,6 +412,18 @@ void XACTSoundBank_Binary::readComplexTrack(Common::SeekableReadStream &xsb, Tra
 				}
 				break;
 
+			case kEventTypeMixBins:
+				xsb.skip(2); // Unused
+
+				for (size_t j = 0; j < ARRAYSIZE(event.params.mixbins.bins) && parameterSize >= 4; j++, parameterSize -= 4) {
+					event.params.mixbins.bins[j].channel = xsb.readByte();
+
+					xsb.skip(1); // Unknown
+
+					event.params.mixbins.bins[j].volume = CLIP(xsb.readSint16LE() / 100.0f, -64.0f, 0.0f);
+				}
+				break;
+
 			default:
 				xsb.skip(2); // Unknown
 				break;