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// Sega VGM music file emulator core
// Game_Music_Emu 0.6-pre
#ifndef VGM_CORE_H
#define VGM_CORE_H
#include "Gme_Loader.h"
#include "Ym2612_Emu.h"
#include "Ym2413_Emu.h"
#include "Sms_Apu.h"
#include "Multi_Buffer.h"
template<class Emu>
class Ym_Emu : public Emu {
int last_time;
short* out;
enum { disabled_time = -1 };
public:
Ym_Emu() { last_time = disabled_time; out = NULL; }
void enable( bool b = true ) { last_time = b ? 0 : disabled_time; }
bool enabled() const { return last_time != disabled_time; }
void begin_frame( short* buf ) { out = buf; last_time = 0; }
int run_until( int time )
{
int count = time - last_time;
if ( count > 0 )
{
if ( last_time < 0 )
return false;
last_time = time;
short* p = out;
out += count * Emu::out_chan_count;
Emu::run( count, p );
}
return true;
}
};
class Vgm_Core : public Gme_Loader {
public:
// VGM file header
struct header_t
{
enum { size = 0x40 };
char tag [4];
byte data_size [4];
byte version [4];
byte psg_rate [4];
byte ym2413_rate [4];
byte gd3_offset [4];
byte track_duration [4];
byte loop_offset [4];
byte loop_duration [4];
byte frame_rate [4];
byte noise_feedback [2];
byte noise_width;
byte unused1;
byte ym2612_rate [4];
byte ym2151_rate [4];
byte data_offset [4];
byte unused2 [8];
// True if header has valid file signature
bool valid_tag() const;
};
// Header for currently loaded file
header_t const& header() const { return *(header_t const*) file_begin(); }
// Raw file data, for parsing GD3 tags
byte const* file_begin() const { return Gme_Loader::file_begin(); }
byte const* file_end () const { return Gme_Loader::file_end(); }
// If file uses FM, initializes FM sound emulator using *sample_rate. If
// *sample_rate is zero, sets *sample_rate to the proper accurate rate and
// uses that. The output of the FM sound emulator is resampled to the
// final sampling rate.
blargg_err_t init_fm( double* sample_rate );
// True if any FM chips are used by file. Always false until init_fm()
// is called.
bool uses_fm() const { return ym2612.enabled() || ym2413.enabled(); }
// Adjusts music tempo, where 1.0 is normal. Can be changed while playing.
// Loading a file resets tempo to 1.0.
void set_tempo( double );
// Starts track
void start_track();
// Runs PSG-only VGM for msec and returns number of clocks it ran for
blip_time_t run_psg( int msec );
// Plays FM for at most count samples into *out, and returns number of
// samples actually generated (always even). Also runs PSG for blip_time.
int play_frame( blip_time_t blip_time, int count, blip_sample_t out [] );
// True if all of file data has been played
bool track_ended() const { return pos >= file_end(); }
// PCM sound is always generated here
Stereo_Buffer stereo_buf;
Blip_Buffer * blip_buf;
// PSG sound chip, for assigning to Blip_Buffer, and setting volume and EQ
Sms_Apu psg;
// PCM synth, for setting volume and EQ
Blip_Synth_Fast pcm;
// FM sound chips
Ym_Emu<Ym2612_Emu> ym2612;
Ym_Emu<Ym2413_Emu> ym2413;
// Implementation
public:
Vgm_Core();
protected:
virtual blargg_err_t load_mem_( byte const [], int );
private:
// blip_time_t // PSG clocks
typedef int vgm_time_t; // 44100 per second, REGARDLESS of sample rate
typedef int fm_time_t; // FM sample count
int vgm_rate; // rate of log, 44100 normally, adjusted by tempo
double fm_rate; // FM samples per second
// VGM to FM time
int fm_time_factor;
int fm_time_offset;
fm_time_t to_fm_time( vgm_time_t ) const;
// VGM to PSG time
int blip_time_factor;
blip_time_t to_psg_time( vgm_time_t ) const;
// Current time and position in log
vgm_time_t vgm_time;
byte const* pos;
byte const* loop_begin;
// PCM
byte const* pcm_data; // location of PCM data in log
byte const* pcm_pos; // current position in PCM data
int dac_amp;
int dac_disabled; // -1 if disabled
void write_pcm( vgm_time_t, int amp );
blip_time_t run( vgm_time_t );
int run_ym2413( int time );
int run_ym2612( int time );
void update_fm_rates( int* ym2413_rate, int* ym2612_rate ) const;
};
#endif
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