Remove GB DMG hacks that were a poor attempt to mimic vgmplay

Frameworks/GME/gme/Gb_Apu.cpp

@@ -161,12 +161,6 @@ void Gb_Apu::set_tempo( double t )
 		frame_period = t ? blip_time_t (frame_period / t) : blip_time_t(0);
 }
 
-void Gb_Apu::set_hacks( unsigned int mask )
-{
-	wave.set_volume_hack((mask & 1) != 0);
-	noise.set_volume_hack((mask & 2) == 0);
-}
-
 Gb_Apu::Gb_Apu()
 {
 	wave.wave_ram = &regs [wave_ram - io_addr];
@@ -193,7 +187,6 @@ Gb_Apu::Gb_Apu()
 	set_tempo( 1.0 );
 	volume_ = 1.0;
 	reset();
-	set_hacks(4);
 }
 
 void Gb_Apu::run_until_( blip_time_t end_time )

Frameworks/GME/gme/Gb_Apu.h

@@ -84,11 +84,6 @@ public:
 	// Loads state. You should call reset() BEFORE this.
 	blargg_err_t load_state( gb_apu_state_t const& in );
 
-	// Enable hacks (bitmask):
-	// 0x01 = Double wave channel volume
-	// 0x02 = Low noise channel volume (disable doubling it)
-	void set_hacks( unsigned int mask );
-
 private:
 	// noncopyable
 	Gb_Apu( const Gb_Apu& );

Frameworks/GME/gme/Gb_Oscs.cpp

@@ -571,7 +571,6 @@ void Gb_Noise::run( blip_time_t time, blip_time_t end_time )
 			Blip_Synth_Fast const* const synth = fast_synth; // cache
 			
 			// Output amplitude transitions
-			if (volume_hack) vol <<= 1;
 			int delta = -vol;
 			do
 			{
@@ -604,11 +603,11 @@ void Gb_Wave::run( blip_time_t time, blip_time_t end_time )
 #if GB_APU_NO_AGB
 	static byte const shifts [4] = { 4+4, 0+4, 1+4, 2+4 };
 	int const volume_idx = regs [2] >> 5 & 3;
-	int const volume_shift = shifts [volume_idx] - (volume_hack ? 1 : 0);
+	int const volume_shift = shifts [volume_idx];
 	int const volume_mul = 1;
 #else
 	static byte const volumes [8] = { 0, 4, 2, 1, 3, 3, 3, 3 };
-	int const volume_shift = 2 + 4 - (volume_hack ? 1 : 0);
+	int const volume_shift = 2 + 4;
 	int const volume_idx = regs [2] >> 5 & (agb_mask | 3); // 2 bits on DMG/CGB, 3 on AGB
 	int const volume_mul = volumes [volume_idx];
 #endif

Frameworks/GME/gme/Gb_Oscs.h

@@ -112,11 +112,8 @@ private:
 
 class Gb_Noise : public Gb_Env {
 public:
-	
 	int divider; // noise has more complex frequency divider setup
 
-	bool volume_hack;
-	
 	void run( blip_time_t, blip_time_t );
 	void write_register( int frame_phase, int reg, int old_data, int data );
 	
@@ -125,11 +122,8 @@ public:
 		divider = 0;
 		Gb_Env::reset();
 		delay = 4 * clk_mul; // TODO: remove?
-		volume_hack = true;
 	}
 
-	void set_volume_hack( bool enable );
-
 private:
 	enum { period2_mask = 0x1FFFF };
 	
@@ -138,14 +132,10 @@ private:
 	unsigned lfsr_mask() const { return (regs [3] & 0x08) ? ~0x4040 : ~0x4000; }
 };
 
-inline void Gb_Noise::set_volume_hack( bool enable ) { volume_hack = enable; }
-
 class Gb_Wave : public Gb_Osc {
 public:
 	int sample_buf; // last wave RAM byte read (hardware has this as well)
 
-	bool volume_hack;
-	
 	void write_register( int frame_phase, int reg, int old_data, int data );
 	void run( blip_time_t, blip_time_t );
 	
@@ -157,7 +147,6 @@ public:
 	{
 		sample_buf = 0;
 		Gb_Osc::reset();
-		volume_hack = false;
 	}
 	
 private:
@@ -177,16 +166,12 @@ private:
 	
 	void corrupt_wave();
 
-	void set_volume_hack( bool enable );
-	
 	BOOST::uint8_t* wave_bank() const { return &wave_ram [(~regs [0] & bank40_mask) >> 2 & agb_mask]; }
 	
 	// Wave index that would be accessed, or -1 if no access would occur
 	int access( int addr ) const;
 };
 
-inline void Gb_Wave::set_volume_hack( bool enable ) { volume_hack = enable; }
-
 inline int Gb_Wave::read( int addr ) const
 {
 	int index = access( addr );

Frameworks/GME/gme/Vgm_Core.cpp

@@ -895,9 +895,6 @@ blargg_err_t Vgm_Core::load_mem_( byte const data [], int size )
 	if ( !gbdmg_rate )
 		gbdmg_rate = Gb_Apu::clock_rate;
 	stereo_buf[3].clock_rate( gbdmg_rate );
-	const int gbdmg_hacks = 3;
-	gbdmg[0].set_hacks( gbdmg_hacks );
-	gbdmg[1].set_hacks( gbdmg_hacks );
 
 	// Disable FM
 	fm_rate = 0;