raze/libraries/game-music-emu/gme/Nes_Fme7_Apu.h
Christoph Oelckers 718112a8fe - added external libraries for music format playback and decompression from GZDoom.
Currently none of these is being used, but eventually they will, once more code gets ported over.
So it's better to have them right away and avoid editing the project file too much, only to revert that later.
2019-09-22 08:59:48 +02:00

131 lines
2.7 KiB
C++

// Sunsoft FME-7 sound emulator
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#ifndef NES_FME7_APU_H
#define NES_FME7_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
struct fme7_apu_state_t
{
enum { reg_count = 14 };
uint8_t regs [reg_count];
uint8_t phases [3]; // 0 or 1
uint8_t latch;
uint16_t delays [3]; // a, b, c
};
class Nes_Fme7_Apu : private fme7_apu_state_t {
public:
// See Nes_Apu.h for reference
void reset();
void volume( double );
void treble_eq( blip_eq_t const& );
void output( Blip_Buffer* );
enum { osc_count = 3 };
void osc_output( int index, Blip_Buffer* );
void end_frame( blip_time_t );
void save_state( fme7_apu_state_t* ) const;
void load_state( fme7_apu_state_t const& );
// Mask and addresses of registers
enum { addr_mask = 0xE000 };
enum { data_addr = 0xE000 };
enum { latch_addr = 0xC000 };
// (addr & addr_mask) == latch_addr
void write_latch( int );
// (addr & addr_mask) == data_addr
void write_data( blip_time_t, int data );
public:
Nes_Fme7_Apu();
BLARGG_DISABLE_NOTHROW
private:
// noncopyable
Nes_Fme7_Apu( const Nes_Fme7_Apu& );
Nes_Fme7_Apu& operator = ( const Nes_Fme7_Apu& );
static unsigned char const amp_table [16];
struct {
Blip_Buffer* output;
int last_amp;
} oscs [osc_count];
blip_time_t last_time;
enum { amp_range = 192 }; // can be any value; this gives best error/quality tradeoff
Blip_Synth<blip_good_quality,1> synth;
void run_until( blip_time_t );
};
inline void Nes_Fme7_Apu::volume( double v )
{
synth.volume( 0.38 / amp_range * v ); // to do: fine-tune
}
inline void Nes_Fme7_Apu::treble_eq( blip_eq_t const& eq )
{
synth.treble_eq( eq );
}
inline void Nes_Fme7_Apu::osc_output( int i, Blip_Buffer* buf )
{
assert( (unsigned) i < osc_count );
oscs [i].output = buf;
}
inline void Nes_Fme7_Apu::output( Blip_Buffer* buf )
{
for ( int i = 0; i < osc_count; i++ )
osc_output( i, buf );
}
inline Nes_Fme7_Apu::Nes_Fme7_Apu()
{
output( NULL );
volume( 1.0 );
reset();
}
inline void Nes_Fme7_Apu::write_latch( int data ) { latch = data; }
inline void Nes_Fme7_Apu::write_data( blip_time_t time, int data )
{
if ( (unsigned) latch >= reg_count )
{
#ifdef debug_printf
debug_printf( "FME7 write to %02X (past end of sound registers)\n", (int) latch );
#endif
return;
}
run_until( time );
regs [latch] = data;
}
inline void Nes_Fme7_Apu::end_frame( blip_time_t time )
{
if ( time > last_time )
run_until( time );
assert( last_time >= time );
last_time -= time;
}
inline void Nes_Fme7_Apu::save_state( fme7_apu_state_t* out ) const
{
*out = *this;
}
inline void Nes_Fme7_Apu::load_state( fme7_apu_state_t const& in )
{
reset();
fme7_apu_state_t* state = this;
*state = in;
}
#endif