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// Turbo Grafx 16 (PC Engine) PSG sound chip emulator
// Game_Music_Emu 0.6-pre
#ifndef HES_APU_H
#define HES_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Hes_Apu {
public:
// Basics
// Sets buffer(s) to generate sound into, or 0 to mute. If only center is not 0,
// output is mono.
void set_output( Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
// Emulates to time t, then writes data to addr
void write_data( blip_time_t t, int addr, int data );
// Emulates to time t, then subtracts t from the current time.
// OK if previous write call had time slightly after t.
void end_frame( blip_time_t t );
// More features
// Resets sound chip
void reset();
// Same as set_output(), but for a particular channel
enum { osc_count = 6 }; // 0 <= chan < osc_count
void set_output( int chan, Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
// Sets treble equalization
void treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
// Sets overall volume, where 1.0 is normal
void volume( double v ) { synth.volume( 1.8 / osc_count / amp_range * v ); }
// Registers are at io_addr to io_addr+io_size-1
enum { io_addr = 0x0800 };
enum { io_size = 10 };
// Implementation
public:
Hes_Apu();
typedef BOOST::uint8_t byte;
private:
enum { amp_range = 0x8000 };
struct Osc
{
byte wave [32];
int delay;
int period;
int phase;
int noise_delay;
byte noise;
unsigned lfsr;
byte control;
byte balance;
byte dac;
short volume [2];
int last_amp [2];
blip_time_t last_time;
Blip_Buffer* output [2];
Blip_Buffer* outputs [3];
};
Osc oscs [osc_count];
int latch;
int balance;
Blip_Synth_Fast synth;
void balance_changed( Osc& );
static void run_osc( Blip_Synth_Fast&, Osc&, blip_time_t );
};
inline void Hes_Apu::set_output( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r )
{
for ( int i = osc_count; --i >= 0; )
set_output( i, c, l, r );
}
#endif
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