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// Sega Master System/Mark III, Sega Genesis/Mega Drive, BBC Micro VGM music file emulator
// Game_Music_Emu 0.5.5
#ifndef VGM_EMU_H
#define VGM_EMU_H
#include "blargg_common.h"
#include "blargg_source.h"
#include "resampler.h"
#include "multi_buffer.h"
#include "ym2413_emu.h"
#include "ym2612_emu.h"
#include "sms_apu.h"
typedef short sample_t;
typedef int vgm_time_t;
typedef int fm_time_t;
enum { fm_time_bits = 12 };
enum { blip_time_bits = 12 };
enum { buf_size = 2048 };
// VGM header format
enum { header_size = 0x40 };
struct header_t
{
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];
};
enum { gme_max_field = 63 };
struct track_info_t
{
/* times in milliseconds; -1 if unknown */
long length;
long intro_length;
long loop_length;
/* empty string if not available */
char game [64];
char song [96];
char author [64];
};
// Emulates VGM music using SN76489/SN76496 PSG, YM2612, and YM2413 FM sound chips.
// Supports custom sound buffer and frequency equalization when VGM uses just the PSG.
// FM sound chips can be run at their proper rates, or slightly higher to reduce
// aliasing on high notes. Currently YM2413 support requires that you supply a
// YM2413 sound chip emulator. I can provide one I've modified to work with the library.
struct Vgm_Emu {
int fm_rate;
long psg_rate;
long vgm_rate;
bool disable_oversampling;
long fm_time_offset;
int fm_time_factor;
int blip_time_factor;
byte const* file_begin;
byte const* file_end;
vgm_time_t vgm_time;
byte const* loop_begin;
byte const* pos;
byte const* pcm_data;
byte const* pcm_pos;
int dac_amp;
int dac_disabled; // -1 if disabled
struct Blip_Buffer* blip_buf;
// general
long clock_rate_;
unsigned buf_changed_count;
int max_initial_silence;
int voice_count;
int mute_mask_;
int tempo;
int gain;
long sample_rate;
// track-specific
blargg_long out_time; // number of samples played since start of track
blargg_long emu_time; // number of samples emulator has generated since start of track
bool emu_track_ended_; // emulator has reached end of track
volatile bool track_ended;
// fading
blargg_long fade_start;
int fade_step;
// silence detection
int silence_lookahead; // speed to run emulator when looking ahead for silence
bool ignore_silence;
long silence_time; // number of samples where most recent silence began
long silence_count; // number of samples of silence to play before using buf
long buf_remain; // number of samples left in silence buffer
// larger items at the end
struct track_info_t info;
sample_t buf_ [buf_size];
struct Ym2612_Emu ym2612;
struct Ym2413_Emu ym2413;
struct Sms_Apu psg;
struct Blip_Synth pcm;
struct Stereo_Buffer stereo_buf;
struct Resampler resampler;
struct Stereo_Buffer buf;
};
void Vgm_init( struct Vgm_Emu* this );
// Disable running FM chips at higher than normal rate. Will result in slightly
// more aliasing of high notes.
static inline void Vgm_disable_oversampling( struct Vgm_Emu* this, bool disable ) { this->disable_oversampling = disable; }
// Header for currently loaded file
static inline struct header_t *header( struct Vgm_Emu* this ) { return (struct header_t*) this->file_begin; }
// Basic functionality (see Gme_File.h for file loading/track info functions)
blargg_err_t Vgm_load_mem( struct Vgm_Emu* this, byte const* new_data, long new_size, bool parse_info );
// True if any FM chips are used by file. Always false until init_fm()
// is called.
static inline bool uses_fm( struct Vgm_Emu* this ) { return Ym2612_enabled( &this->ym2612 ) || Ym2413_enabled( &this->ym2413 ); }
// Set output sample rate. Must be called only once before loading file.
blargg_err_t Vgm_set_sample_rate( struct Vgm_Emu* this, long sample_rate );
// Start a track, where 0 is the first track. Also clears warning string.
blargg_err_t Vgm_start_track( struct Vgm_Emu* this );
// Generate 'count' samples info 'buf'. Output is in stereo. Any emulation
// errors set warning string, and major errors also end track.
blargg_err_t Vgm_play( struct Vgm_Emu* this, long count, sample_t* buf );
// Track status/control
// Number of milliseconds (1000 msec = 1 second) played since beginning of track
long Track_tell( struct Vgm_Emu* this );
// Seek to new time in track. Seeking backwards or far forward can take a while.
blargg_err_t Track_seek( struct Vgm_Emu* this, long msec );
// Skip n samples
blargg_err_t Track_skip( struct Vgm_Emu* this, long n );
// Set start time and length of track fade out. Once fade ends track_ended() returns
// true. Fade time can be changed while track is playing.
void Track_set_fade( struct Vgm_Emu* this, long start_msec, long length_msec );
// Get track length in milliseconds
static inline long Track_get_length( struct Vgm_Emu* this )
{
long length = this->info.length;
if ( length <= 0 )
{
length = this->info.intro_length + 2 * this->info.loop_length; // intro + 2 loops
if ( length <= 0 )
length = 150 * 1000; // 2.5 minutes
}
return length;
}
// Sound customization
// Adjust song tempo, where 1.0 = normal, 0.5 = half speed, 2.0 = double speed.
// Track length as returned by track_info() assumes a tempo of 1.0.
void Sound_set_tempo( struct Vgm_Emu* this, int t );
// Mute/unmute voice i, where voice 0 is first voice
void Sound_mute_voice( struct Vgm_Emu* this, int index, bool mute );
// Set muting state of all voices at once using a bit mask, where -1 mutes them all,
// 0 unmutes them all, 0x01 mutes just the first voice, etc.
void Sound_mute_voices( struct Vgm_Emu* this, int mask );
// Change overall output amplitude, where 1.0 results in minimal clamping.
// Must be called before set_sample_rate().
static inline void Sound_set_gain( struct Vgm_Emu* this, int g )
{
assert( !this->sample_rate ); // you must set gain before setting sample rate
this->gain = g;
}
#endif
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