qzdoom/game-music-emu/gme/Kss_Scc_Apu.h

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// Konami SCC sound chip emulator
// Game_Music_Emu 0.6.0
#ifndef KSS_SCC_APU_H
#define KSS_SCC_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
#include <string.h>
class Scc_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 = 0x90 };
void write( blip_time_t time, int reg, 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 to 4. If buffer is NULL, the specified oscillator is muted.
enum { osc_count = 5 };
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:
Scc_Apu();
private:
enum { amp_range = 0x8000 };
struct osc_t
{
int delay;
int phase;
int last_amp;
Blip_Buffer* output;
};
osc_t oscs [osc_count];
blip_time_t last_time;
unsigned char regs [reg_count];
Blip_Synth<blip_med_quality,1> synth;
void run_until( blip_time_t );
};
inline void Scc_Apu::volume( double v ) { synth.volume( 0.43 / osc_count / amp_range * v ); }
inline void Scc_Apu::treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
inline void Scc_Apu::osc_output( int index, Blip_Buffer* b )
{
assert( (unsigned) index < osc_count );
oscs [index].output = b;
}
inline void Scc_Apu::write( blip_time_t time, int addr, int data )
{
assert( (unsigned) addr < reg_count );
run_until( time );
regs [addr] = data;
}
inline void Scc_Apu::end_frame( blip_time_t end_time )
{
if ( end_time > last_time )
run_until( end_time );
last_time -= end_time;
assert( last_time >= 0 );
}
inline void Scc_Apu::output( Blip_Buffer* buf )
{
for ( int i = 0; i < osc_count; i++ )
oscs [i].output = buf;
}
inline Scc_Apu::Scc_Apu()
{
output( 0 );
}
inline void Scc_Apu::reset()
{
last_time = 0;
for ( int i = 0; i < osc_count; i++ )
memset( &oscs [i], 0, offsetof (osc_t,output) );
memset( regs, 0, sizeof regs );
}
#endif