raze-gles/libraries/game-music-emu/gme/Gb_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

90 lines
2.5 KiB
C++

// Nintendo Game Boy PAPU sound chip emulator
// Gb_Snd_Emu 0.1.5
#ifndef GB_APU_H
#define GB_APU_H
#include "Gb_Oscs.h"
class Gb_Apu {
public:
// Set overall volume of all oscillators, where 1.0 is full volume
void volume( double );
// Set treble equalization
void treble_eq( const blip_eq_t& );
// Outputs can be assigned to a single buffer for mono output, or to three
// buffers for stereo output (using Stereo_Buffer to do the mixing).
// Assign all oscillator outputs to specified buffer(s). If buffer
// is NULL, silences all oscillators.
void output( Blip_Buffer* mono );
void output( Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
// Assign single oscillator output to buffer(s). Valid indicies are 0 to 3,
// which refer to Square 1, Square 2, Wave, and Noise. If buffer is NULL,
// silences oscillator.
enum { osc_count = 4 };
void osc_output( int index, Blip_Buffer* mono );
void osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
// Reset oscillators and internal state
void reset();
// Reads and writes at addr must satisfy start_addr <= addr <= end_addr
enum { start_addr = 0xFF10 };
enum { end_addr = 0xFF3F };
enum { register_count = end_addr - start_addr + 1 };
// Write 'data' to address at specified time
void write_register( blip_time_t, unsigned addr, int data );
// Read from address at specified time
int read_register( blip_time_t, unsigned addr );
// Run all oscillators up to specified time, end current time frame, then
// start a new frame at time 0.
void end_frame( blip_time_t );
void set_tempo( double );
public:
Gb_Apu();
private:
// noncopyable
Gb_Apu( const Gb_Apu& );
Gb_Apu& operator = ( const Gb_Apu& );
Gb_Osc* oscs [osc_count];
blip_time_t next_frame_time;
blip_time_t last_time;
blip_time_t frame_period;
double volume_unit;
int frame_count;
Gb_Square square1;
Gb_Square square2;
Gb_Wave wave;
Gb_Noise noise;
uint8_t regs [register_count];
Gb_Square::Synth square_synth; // used by squares
Gb_Wave::Synth other_synth; // used by wave and noise
void update_volume();
void run_until( blip_time_t );
void write_osc( int index, int reg, int data );
};
inline void Gb_Apu::output( Blip_Buffer* b ) { output( b, b, b ); }
inline void Gb_Apu::osc_output( int i, Blip_Buffer* b ) { osc_output( i, b, b, b ); }
inline void Gb_Apu::volume( double vol )
{
volume_unit = 0.60 / osc_count / 15 /*steps*/ / 2 /*?*/ / 8 /*master vol range*/ * vol;
update_volume();
}
#endif