cog/Frameworks/GME/gme/Sap_Apu.h

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// Atari POKEY sound chip emulator
// Game_Music_Emu $vers
#ifndef SAP_APU_H
#define SAP_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Sap_Apu_Impl;
class Sap_Apu {
public:
// Basics
// Sets buffer to generate sound into, or 0 to mute
void set_output( Blip_Buffer* );
// 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
// Same as set_output(), but for a particular channel
enum { osc_count = 4 };
void set_output( int index, Blip_Buffer* );
// Resets sound chip and sets Sap_Apu_Impl
void reset( Sap_Apu_Impl* impl );
// Registers are at io_addr to io_addr+io_size-1
enum { io_addr = 0xD200 };
enum { io_size = 0x0A };
private:
// noncopyable
Sap_Apu( const Sap_Apu& );
Sap_Apu& operator = ( const Sap_Apu& );
// Implementation
public:
Sap_Apu();
private:
struct osc_t
{
unsigned char regs [2];
unsigned char phase;
unsigned char invert;
int last_amp;
blip_time_t delay;
blip_time_t period; // always recalculated before use; here for convenience
Blip_Buffer* output;
};
osc_t oscs [osc_count];
Sap_Apu_Impl* impl;
blip_time_t last_time;
int poly5_pos;
int poly4_pos;
int polym_pos;
int control;
void calc_periods();
void run_until( blip_time_t );
enum { poly4_len = (1 << 4) - 1 };
enum { poly9_len = (1 << 9) - 1 };
enum { poly17_len = (1 << 17) - 1 };
friend class Sap_Apu_Impl;
};
// Common tables and Blip_Synth that can be shared among multiple Sap_Apu objects
class Sap_Apu_Impl {
public:
// Set treble with synth.treble_eq()
Blip_Synth_Norm synth;
// Sets overall volume, where 1.0is normal
void volume( double d ) { synth.volume( 1.0 / Sap_Apu::osc_count / 30 * d ); }
// Implementation
public:
Sap_Apu_Impl();
private:
BOOST::uint8_t poly4 [Sap_Apu::poly4_len /8 + 1];
BOOST::uint8_t poly9 [Sap_Apu::poly9_len /8 + 1];
BOOST::uint8_t poly17 [Sap_Apu::poly17_len/8 + 1];
friend class Sap_Apu;
};
inline void Sap_Apu::set_output( int i, Blip_Buffer* b )
{
assert( (unsigned) i < osc_count );
oscs [i].output = b;
}
#endif