RAD player: fix wrong KSL (key scale shift) values

internal/c/parts/audio/extras/radv2/opal.cpp

@@ -38,7 +38,7 @@ class Opal {
         EnvAtt,
         EnvDec,
         EnvSus,
-        EnvRel,
+        EnvRel
     };
 
     // A single FM operator

internal/c/parts/audio/extras/radv2/player20.cpp

@@ -162,6 +162,7 @@ class RADPlayer {
     void Init10(const void *tune);
     bool UnpackNote10(uint8_t *&s);
     uint8_t *SkipToLine10(uint8_t *trk, uint8_t linenum);
+    uint8_t FixRadv21KSLVolume(uint8_t val);
     int LastPatternOrder;
     bool Is10;
 
@@ -326,8 +327,11 @@ void RADPlayer::Init(const void *tune, void (*opl3)(void *, uint16_t, uint8_t),
 
             for (int i = 0; i < 4; i++) {
                 uint8_t *op = inst.Operators[i];
-                for (int j = 0; j < 5; j++)
-                    op[j] = *s++;
+                op[0] = *s++;
+                op[1] = FixRadv21KSLVolume(*s++);
+                op[2] = *s++;
+                op[3] = *s++;
+                op[4] = *s++;
             }
 
         } else {
@@ -1417,6 +1421,14 @@ uint8_t *RADPlayer::SkipToLine10(uint8_t *trk, uint8_t linenum) {
     return 0;
 }
 
+//==================================================================================================
+// KSL is handled different between RAD v1 / DOS RAD v2.1 and Windows/Mac RAD v2.1.
+// In DOS, since these are passed directly to the OPL3, KSL 1 is 3dB and KSL 2 is 1.5dB.
+// With Opal, these were originally reversed, so flip the KSL bits when loading RAD v2s.
+// -Lachesis
+//==================================================================================================
+uint8_t RADPlayer::FixRadv21KSLVolume(uint8_t val) { return ((val & 0x80) >> 1) | ((val & 0x40) << 1) | (val & 0x3F); }
+
 //==================================================================================================
 // Set the current order and line. -Lachesis
 //==================================================================================================