129 lines
3.7 KiB
C++
129 lines
3.7 KiB
C++
// Sega Master System SN76489 PSG sound chip emulator
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// Sms_Snd_Emu $vers
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#ifndef SMS_APU_H
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#define SMS_APU_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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struct sms_apu_state_t;
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class Sms_Apu {
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public:
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// Basics
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// Sets buffer(s) to generate sound into, or 0 to mute. If only center is not 0,
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// output is mono.
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void set_output( Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
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// Emulates to time t, then writes data to Game Gear left/right assignment byte
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void write_ggstereo( blip_time_t t, int data );
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// Emulates to time t, then writes data
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void write_data( blip_time_t t, int data );
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// Emulates to time t, then subtracts t from the current time.
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// OK if previous write call had time slightly after t.
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void end_frame( blip_time_t t );
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// More features
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// Resets sound chip and sets noise feedback bits and width
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void reset( unsigned noise_feedback = 0, int noise_width = 0 );
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// Same as set_output(), but for a particular channel
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// 0: Square 1, 1: Square 2, 2: Square 3, 3: Noise
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enum { osc_count = 4 }; // 0 <= chan < osc_count
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void set_output( int chan, Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
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// Sets overall volume, where 1.0 is normal
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void volume( double );
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// Sets treble equalization
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void treble_eq( blip_eq_t const& );
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// Saves full emulation state to state_out. Data format is portable and
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// includes some extra space to avoid expansion in case more state needs
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// to be stored in the future.
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void save_state( sms_apu_state_t* state_out );
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// Loads state. You should call reset() BEFORE this.
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blargg_err_t load_state( sms_apu_state_t const& in );
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private:
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// noncopyable
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Sms_Apu( const Sms_Apu& );
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Sms_Apu& operator = ( const Sms_Apu& );
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// Implementation
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public:
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Sms_Apu();
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~Sms_Apu() { }
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BLARGG_DISABLE_NOTHROW
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// Use set_output() instead
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BLARGG_DEPRECATED( void output ( Blip_Buffer* c ) { set_output( c, c, c ); } )
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BLARGG_DEPRECATED( void output ( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r ) { set_output( c, l, r ); } )
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BLARGG_DEPRECATED( void osc_output( int i, Blip_Buffer* c ) { set_output( i, c, c, c ); } )
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BLARGG_DEPRECATED( void osc_output( int i, Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r ) { set_output( i, c, l, r ); } )
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private:
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struct Osc
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{
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Blip_Buffer* outputs [4]; // NULL, right, left, center
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Blip_Buffer* output;
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int last_amp;
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int volume;
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int period;
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int delay;
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unsigned phase;
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};
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Osc oscs [osc_count];
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int ggstereo;
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int latch;
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blip_time_t last_time;
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int min_tone_period;
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unsigned noise_feedback;
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unsigned looped_feedback;
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Blip_Synth_Fast fast_synth;
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Blip_Synth_Norm norm_synth;
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int calc_output( int i ) const;
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void run_until( blip_time_t );
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const char* save_load( sms_apu_state_t*, bool save );
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friend class Sms_Apu_Tester;
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};
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struct sms_apu_state_t
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{
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// If SMS_APU_CUSTOM_STATE is 1, values are stored as normal integers,
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// so your code can then save and load them however it likes. Otherwise,
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// they are 4-byte arrays in little-endian format, making entire
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// structure suitable for direct storage on disk.
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#if SMS_APU_CUSTOM_STATE
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typedef int val_t;
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#else
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typedef unsigned char val_t [4];
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#endif
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enum { format0 = 0x50414D53 };
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val_t format;
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val_t version;
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val_t latch;
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val_t ggstereo;
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val_t periods [4];
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val_t volumes [4];
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val_t delays [4];
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val_t phases [4];
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val_t unused [12]; // for future expansion
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};
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#endif
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