[scripts] Génération de fichiers midi

#define mid_init
//mid_ini(file)
file_text_close( file_text_open_write(argument0) )
global._cMidiFile = file_bin_open(argument0, 1)
#define mid_end
file_bin_close(global._cMidiFile)
#define mid_MThd
//mid_MThd(divisions)

//Header Chunk
//the literal string MThd, or in hexadecimal notation: 0x4d546864.
//These four characters at the start of the MIDI file indicate that this is a MIDI file.
// header_chunk = "MThd" + <header_length> + <format> + <n> + <division>
file_bin_write_byte(global._cMidiFile,77)
file_bin_write_byte(global._cMidiFile,84)
file_bin_write_byte(global._cMidiFile,104)
file_bin_write_byte(global._cMidiFile,100)
//<header_length> 4 bytes
//length of the header chunk (always 6 bytes long--the size of the next
//three fields which are considered the header chunk).
file_bin_write_byte(global._cMidiFile,0)
file_bin_write_byte(global._cMidiFile,0)
file_bin_write_byte(global._cMidiFile,0)
file_bin_write_byte(global._cMidiFile,6)
//<format> 2 bytes
//0 = single track file format
//1 = multiple track file format
//2 = multiple song file format (i.e., a series of type 0 files)
file_bin_write_byte(global._cMidiFile,0)
file_bin_write_byte(global._cMidiFile,1)
//<n> 2 bytes
//number of track chunks that follow the header chunk
file_bin_write_byte(global._cMidiFile,0)
file_bin_write_byte(global._cMidiFile,1)
//<division> 2 bytes
//unit of time for delta timing. If the value is positive, then it represents
//the units per beat. For example, +96 would mean 96 ticks per beat.
//If the value is negative, delta times are in SMPTE compatible units.
file_bin_write_byte(global._cMidiFile, argument0>>8)
file_bin_write_byte(global._cMidiFile, argument0&255)

#define mid_MTrk
//mid_MTrk(tempo size, instrument size, note on, note off, note off all, end)
//Track Chunk
//A track chunk consists of a literal identifier string, a length indicator
//specifying the size of the track, and actual event data making up the track.
//track_chunk = "MTrk" + <length> + <track_event> [+ <track_event> ...]
//"MTrk" 4 bytes
//the literal string MTrk. This marks the beginning of a track.
file_bin_write_byte(global._cMidiFile,77)
file_bin_write_byte(global._cMidiFile,84)
file_bin_write_byte(global._cMidiFile,114)
file_bin_write_byte(global._cMidiFile,107)
size=5*(argument2+argument3+argument4+argument5)+argument0*8+argument1*4+argument6
//<length> 4 bytes
//the number of bytes in the track chunk following this number.
file_bin_write_byte(global._cMidiFile, size>>24)
file_bin_write_byte(global._cMidiFile, (size>>16)&255)
file_bin_write_byte(global._cMidiFile, (size>>8)&255)
file_bin_write_byte(global._cMidiFile, size&255)

//...
//<track_event> : a sequenced track event.
#define mid_MTrk_tempo
//mid_MTrk_tempo(delta time, tempo)

//Tempo
dtime = argument0
dtime += 0.00001

file_bin_write_byte(global._cMidiFile, $80+floor(dtime/128))
file_bin_write_byte(global._cMidiFile, ((dtime/128)-floor(dtime/128))*128)
file_bin_write_byte(global._cMidiFile, $FF)
file_bin_write_byte(global._cMidiFile, $51)
file_bin_write_byte(global._cMidiFile, $03)

file_bin_write_byte(global._cMidiFile, argument1>>16)
file_bin_write_byte(global._cMidiFile, (argument1>>8)&255)
file_bin_write_byte(global._cMidiFile, argument1 & 255)
#define mid_MTrk_instrument
//mid_MTrk_instrument(delta time, chanel, instrument)
dtime = argument0
dtime += 0.00001
file_bin_write_byte(global._cMidiFile, $80+floor(dtime/128))
file_bin_write_byte(global._cMidiFile, ((dtime/128)-floor(dtime/128))*128)
file_bin_write_byte(global._cMidiFile, $C0+argument1)
file_bin_write_byte(global._cMidiFile, argument2)
#define mid_MTrk_play_note
//mid_MTrk_play_note(delta time, chanel, note, volume)
dtime = argument0
dtime += 0.00001
file_bin_write_byte(global._cMidiFile, $80+floor(dtime/128))
file_bin_write_byte(global._cMidiFile, ((dtime/128)-floor(dtime/128))*128)
file_bin_write_byte(global._cMidiFile, $90 + argument1)
file_bin_write_byte(global._cMidiFile, argument2)
file_bin_write_byte(global._cMidiFile, argument3)

#define mid_MTrk_stop_note
//mid_MTrk_stop_note(delta time, chanel)
dtime = argument0
dtime += 0.00001
file_bin_write_byte(global._cMidiFile, $80+floor(dtime/128))
file_bin_write_byte(global._cMidiFile, ((dtime/128)-floor(dtime/128))*128)
file_bin_write_byte(global._cMidiFile, $80 + argument1)
file_bin_write_byte(global._cMidiFile, argument2)
file_bin_write_byte(global._cMidiFile, 0)
#define mid_MTrk_end
dtime = argument0
dtime += 0.00001
file_bin_write_byte(global._cMidiFile, $80+floor(dtime/128))
file_bin_write_byte(global._cMidiFile, ((dtime/128)-floor(dtime/128))*128)
file_bin_write_byte(global._cMidiFile, $FF)
file_bin_write_byte(global._cMidiFile, $2F)
file_bin_write_byte(global._cMidiFile, 0)

nbNotes = 30

mid_init("out.mid")
mid_MThd(900)
mid_MTrk(1,1,nbNotes,nbNotes,0,1)

mid_MTrk_tempo(0,500000)
mid_MTrk_instrument(0,0, M_PIANO) //M_PIANO = 0

for(i=0; i<nbNotes; i+=1)
{
note = 60 + (i*i mod 20)
note = round(note)
mid_MTrk_play_note(0,0,note,90)
mid_MTrk_stop_note(900,0,note)
}

mid_MTrk_end(0)
mid_end()

sound = sound_add('out.mid', 1, 1)
sound_loop(sound)