cog/Frameworks/GME/gme/Sms_Apu.h

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// Sega Master System SN76489 PSG sound chip emulator
// Sms_Snd_Emu $vers
#ifndef SMS_APU_H
#define SMS_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
struct sms_apu_state_t;
class Sms_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 Game Gear left/right assignment byte
void write_ggstereo( blip_time_t t, int data );
// Emulates to time t, then writes data
void write_data( blip_time_t t, 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 and sets noise feedback bits and width
void reset( unsigned noise_feedback = 0, int noise_width = 0 );
// Same as set_output(), but for a particular channel
// 0: Square 1, 1: Square 2, 2: Square 3, 3: Noise
enum { osc_count = 4 }; // 0 <= chan < osc_count
void set_output( int chan, Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
// Sets overall volume, where 1.0 is normal
void volume( double );
// Sets treble equalization
void treble_eq( blip_eq_t const& );
// Saves full emulation state to state_out. Data format is portable and
// includes some extra space to avoid expansion in case more state needs
// to be stored in the future.
void save_state( sms_apu_state_t* state_out );
// Loads state. You should call reset() BEFORE this.
blargg_err_t load_state( sms_apu_state_t const& in );
private:
// noncopyable
Sms_Apu( const Sms_Apu& );
Sms_Apu& operator = ( const Sms_Apu& );
// Implementation
public:
Sms_Apu();
~Sms_Apu() { }
BLARGG_DISABLE_NOTHROW
// Use set_output() instead
BLARGG_DEPRECATED( void output ( Blip_Buffer* c ) { set_output( c, c, c ); } )
BLARGG_DEPRECATED( void output ( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r ) { set_output( c, l, r ); } )
BLARGG_DEPRECATED( void osc_output( int i, Blip_Buffer* c ) { set_output( i, c, c, c ); } )
BLARGG_DEPRECATED( void osc_output( int i, Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r ) { set_output( i, c, l, r ); } )
private:
struct Osc
{
Blip_Buffer* outputs [4]; // NULL, right, left, center
Blip_Buffer* output;
int last_amp;
int volume;
int period;
int delay;
unsigned phase;
};
Osc oscs [osc_count];
int ggstereo;
int latch;
blip_time_t last_time;
int min_tone_period;
unsigned noise_feedback;
unsigned looped_feedback;
Blip_Synth_Fast fast_synth;
Blip_Synth_Norm norm_synth;
int calc_output( int i ) const;
void run_until( blip_time_t );
const char* save_load( sms_apu_state_t*, bool save );
friend class Sms_Apu_Tester;
};
struct sms_apu_state_t
{
// If SMS_APU_CUSTOM_STATE is 1, values are stored as normal integers,
// so your code can then save and load them however it likes. Otherwise,
// they are 4-byte arrays in little-endian format, making entire
// structure suitable for direct storage on disk.
#if SMS_APU_CUSTOM_STATE
typedef int val_t;
#else
typedef unsigned char val_t [4];
#endif
enum { format0 = 0x50414D53 };
val_t format;
val_t version;
val_t latch;
val_t ggstereo;
val_t periods [4];
val_t volumes [4];
val_t delays [4];
val_t phases [4];
val_t unused [12]; // for future expansion
};
#endif