- Move panning volume calculation out of the OPL chips and into the player.

SVN r3948 (trunk)

src/oplsynth/dosbox/opl.h

@@ -223,7 +223,7 @@ public:
 	void Reset();
 	void Update(float* sndptr, int numsamples);
 	void WriteReg(int idx, int val);
-	void SetPanning(int c, int pan);
+	void SetPanning(int c, float left, float right);
 
 	DBOPL(bool stereo);
 };

src/oplsynth/fmopl.cpp

@@ -127,7 +127,6 @@ typedef signed int		INT32;   /* signed 32bit   */
 #endif
 
 #define CENTER_PANNING_POWER	0.70710678118	/* [RH] volume at center for EQP */
-#define HALF_PI					(PI/2)
 
 #define FREQ_SH			16  /* 16.16 fixed point (frequency calculations) */
 #define EG_SH			16  /* 16.16 fixed point (EG timing)              */
@@ -1587,13 +1586,10 @@ public:
 	}
 
 	/* [RH] Full support for MIDI panning */
-	void SetPanning(int c, int pan)
+	void SetPanning(int c, float left, float right)
 	{
-		// This is the MIDI-recommended pan formula. 0 and 1 are
-		// both hard left so that 64 can be perfectly center.
-		double level = (pan <= 1) ? 0 : (pan - 1) / 126.0;
-		Chip.P_CH[c].LeftVol = (float)cos(HALF_PI * level);
-		Chip.P_CH[c].RightVol = (float)sin(HALF_PI * level);
+		Chip.P_CH[c].LeftVol = left;
+		Chip.P_CH[c].RightVol = right;
 	}
 
 

src/oplsynth/mlopl_io.cpp

@@ -45,6 +45,8 @@
 #include "opl.h"
 #include "c_cvars.h"
 
+#define HALF_PI (PI*0.5)
+
 EXTERN_CVAR(Int, opl_core)
 
 OPLio::~OPLio()
@@ -260,7 +262,13 @@ void OPLio::OPLwritePan(uint channel, struct OPL2instrument *instr, int pan)
 		int which = channel / chanper;
 		if (chips[which] != NULL)
 		{
-			chips[which]->SetPanning(channel % chanper, pan + 64);
+			// This is the MIDI-recommended pan formula. 0 and 1 are
+			// both hard left so that 64 can be perfectly center.
+			// (Note that the 'pan' passed to this function is the
+			// MIDI pan position, subtracted by 64.)
+			double level = (pan <= -63) ? 0 : (pan + 64 - 1) / 126.0;
+			chips[which]->SetPanning(channel % chanper,
+				(float)cos(HALF_PI * level), (float)sin(HALF_PI * level));
 		}
 	}
 }

src/oplsynth/opl.h

@@ -14,7 +14,7 @@ public:
 	virtual void Reset() = 0;
 	virtual void WriteReg(int reg, int v) = 0;
 	virtual void Update(float *buffer, int length) = 0;
-	virtual void SetPanning(int c, int pan) = 0;
+	virtual void SetPanning(int c, float left, float right) = 0;
 	virtual FString GetVoiceString() { return FString(); }
 };