// AY-3-8910 sound chip emulator // Game_Music_Emu 0.5.2 #ifndef AY_APU_H #define AY_APU_H #include "blargg_common.h" #include "Blip_Buffer.h" class Ay_Apu { public: // Set buffer to generate all sound into, or disable sound if NULL void output( Blip_Buffer* ); // Reset sound chip void reset(); // Write to register at specified time enum { reg_count = 16 }; void write( blip_time_t time, int addr, int data ); // Run sound to specified time, end current time frame, then start a new // time frame at time 0. Time frames have no effect on emulation and each // can be whatever length is convenient. void end_frame( blip_time_t length ); // Additional features // Set sound output of specific oscillator to buffer, where index is // 0, 1, or 2. If buffer is NULL, the specified oscillator is muted. enum { osc_count = 3 }; void osc_output( int index, Blip_Buffer* ); // Set overall volume (default is 1.0) void volume( double ); // Set treble equalization (see documentation) void treble_eq( blip_eq_t const& ); public: Ay_Apu(); typedef unsigned char byte; private: struct osc_t { blip_time_t period; blip_time_t delay; short last_amp; short phase; Blip_Buffer* output; } oscs [osc_count]; blip_time_t last_time; byte latch; byte regs [reg_count]; struct { blip_time_t delay; blargg_ulong lfsr; } noise; struct { blip_time_t delay; byte const* wave; int pos; byte modes [8] [48]; // values already passed through volume table } env; void run_until( blip_time_t ); void write_data_( int addr, int data ); public: enum { amp_range = 255 }; Blip_Synth<blip_good_quality,1> synth_; }; inline void Ay_Apu::volume( double v ) { synth_.volume( 0.7 / osc_count / amp_range * v ); } inline void Ay_Apu::treble_eq( blip_eq_t const& eq ) { synth_.treble_eq( eq ); } inline void Ay_Apu::write( blip_time_t time, int addr, int data ) { run_until( time ); write_data_( addr, data ); } inline void Ay_Apu::osc_output( int i, Blip_Buffer* buf ) { assert( (unsigned) i < osc_count ); oscs [i].output = buf; } inline void Ay_Apu::output( Blip_Buffer* buf ) { osc_output( 0, buf ); osc_output( 1, buf ); osc_output( 2, buf ); } inline void Ay_Apu::end_frame( blip_time_t time ) { if ( time > last_time ) run_until( time ); assert( last_time >= time ); last_time -= time; } #endif