raze-gles/libraries/game-music-emu/gme/Vgm_Emu_Impl.cpp
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

314 lines
6.6 KiB
C++

// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#include "Vgm_Emu.h"
#include <math.h>
#include <string.h>
#include "blargg_endian.h"
/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
#include "blargg_source.h"
enum {
cmd_gg_stereo = 0x4F,
cmd_psg = 0x50,
cmd_ym2413 = 0x51,
cmd_ym2612_port0 = 0x52,
cmd_ym2612_port1 = 0x53,
cmd_ym2151 = 0x54,
cmd_delay = 0x61,
cmd_delay_735 = 0x62,
cmd_delay_882 = 0x63,
cmd_byte_delay = 0x64,
cmd_end = 0x66,
cmd_data_block = 0x67,
cmd_short_delay = 0x70,
cmd_pcm_delay = 0x80,
cmd_pcm_seek = 0xE0,
pcm_block_type = 0x00,
ym2612_dac_port = 0x2A
};
inline int command_len( int command )
{
switch ( command >> 4 )
{
case 0x03:
case 0x04:
return 2;
case 0x05:
case 0x0A:
case 0x0B:
return 3;
case 0x0C:
case 0x0D:
return 4;
case 0x0E:
case 0x0F:
return 5;
}
check( false );
return 1;
}
template<class Emu>
inline void Ym_Emu<Emu>::begin_frame( short* p )
{
require( enabled() );
out = p;
last_time = 0;
}
template<class Emu>
inline int Ym_Emu<Emu>::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;
}
inline Vgm_Emu_Impl::fm_time_t Vgm_Emu_Impl::to_fm_time( vgm_time_t t ) const
{
return (t * fm_time_factor + fm_time_offset) >> fm_time_bits;
}
inline blip_time_t Vgm_Emu_Impl::to_blip_time( vgm_time_t t ) const
{
return (t * blip_time_factor) >> blip_time_bits;
}
void Vgm_Emu_Impl::write_pcm( vgm_time_t vgm_time, int amp )
{
blip_time_t blip_time = to_blip_time( vgm_time );
int old = dac_amp;
int delta = amp - old;
dac_amp = amp;
if ( old >= 0 )
dac_synth.offset_inline( blip_time, delta, &blip_buf );
else
dac_amp |= dac_disabled;
}
blip_time_t Vgm_Emu_Impl::run_commands( vgm_time_t end_time )
{
vgm_time_t vgm_time = this->vgm_time;
byte const* pos = this->pos;
if ( pos >= data_end )
{
set_track_ended();
if ( pos > data_end )
set_warning( "Stream lacked end event" );
}
while ( vgm_time < end_time && pos < data_end )
{
// TODO: be sure there are enough bytes left in stream for particular command
// so we don't read past end
switch ( *pos++ )
{
case cmd_end:
pos = loop_begin; // if not looped, loop_begin == data_end
break;
case cmd_delay_735:
vgm_time += 735;
break;
case cmd_delay_882:
vgm_time += 882;
break;
case cmd_gg_stereo:
psg.write_ggstereo( to_blip_time( vgm_time ), *pos++ );
break;
case cmd_psg:
psg.write_data( to_blip_time( vgm_time ), *pos++ );
break;
case cmd_delay:
vgm_time += pos [1] * 0x100L + pos [0];
pos += 2;
break;
case cmd_byte_delay:
vgm_time += *pos++;
break;
case cmd_ym2413:
if ( ym2413.run_until( to_fm_time( vgm_time ) ) )
ym2413.write( pos [0], pos [1] );
pos += 2;
break;
case cmd_ym2612_port0:
if ( pos [0] == ym2612_dac_port )
{
write_pcm( vgm_time, pos [1] );
}
else if ( ym2612.run_until( to_fm_time( vgm_time ) ) )
{
if ( pos [0] == 0x2B )
{
dac_disabled = (pos [1] >> 7 & 1) - 1;
dac_amp |= dac_disabled;
}
ym2612.write0( pos [0], pos [1] );
}
pos += 2;
break;
case cmd_ym2612_port1:
if ( ym2612.run_until( to_fm_time( vgm_time ) ) )
ym2612.write1( pos [0], pos [1] );
pos += 2;
break;
case cmd_data_block: {
check( *pos == cmd_end );
int type = pos [1];
long size = get_le32( pos + 2 );
pos += 6;
if ( type == pcm_block_type )
pcm_data = pos;
pos += size;
break;
}
case cmd_pcm_seek:
pcm_pos = pcm_data + pos [3] * 0x1000000L + pos [2] * 0x10000L +
pos [1] * 0x100L + pos [0];
pos += 4;
break;
default:
int cmd = pos [-1];
switch ( cmd & 0xF0 )
{
case cmd_pcm_delay:
write_pcm( vgm_time, *pcm_pos++ );
vgm_time += cmd & 0x0F;
break;
case cmd_short_delay:
vgm_time += (cmd & 0x0F) + 1;
break;
case 0x50:
pos += 2;
break;
default:
pos += command_len( cmd ) - 1;
set_warning( "Unknown stream event" );
}
}
}
vgm_time -= end_time;
this->pos = pos;
this->vgm_time = vgm_time;
return to_blip_time( end_time );
}
int Vgm_Emu_Impl::play_frame( blip_time_t blip_time, int sample_count, sample_t* buf )
{
// to do: timing is working mostly by luck
int min_pairs = sample_count >> 1;
int vgm_time = ((long) min_pairs << fm_time_bits) / fm_time_factor - 1;
assert( to_fm_time( vgm_time ) <= min_pairs );
int pairs = min_pairs;
while ( (pairs = to_fm_time( vgm_time )) < min_pairs )
vgm_time++;
//debug_printf( "pairs: %d, min_pairs: %d\n", pairs, min_pairs );
if ( ym2612.enabled() )
{
ym2612.begin_frame( buf );
memset( buf, 0, pairs * stereo * sizeof *buf );
}
else if ( ym2413.enabled() )
{
ym2413.begin_frame( buf );
}
run_commands( vgm_time );
ym2612.run_until( pairs );
ym2413.run_until( pairs );
fm_time_offset = (vgm_time * fm_time_factor + fm_time_offset) -
((long) pairs << fm_time_bits);
psg.end_frame( blip_time );
return pairs * stereo;
}
// Update pre-1.10 header FM rates by scanning commands
void Vgm_Emu_Impl::update_fm_rates( long* ym2413_rate, long* ym2612_rate ) const
{
byte const* p = data + 0x40;
while ( p < data_end )
{
switch ( *p )
{
case cmd_end:
return;
case cmd_psg:
case cmd_byte_delay:
p += 2;
break;
case cmd_delay:
p += 3;
break;
case cmd_data_block:
p += 7 + get_le32( p + 3 );
break;
case cmd_ym2413:
*ym2612_rate = 0;
return;
case cmd_ym2612_port0:
case cmd_ym2612_port1:
*ym2612_rate = *ym2413_rate;
*ym2413_rate = 0;
return;
case cmd_ym2151:
*ym2413_rate = 0;
*ym2612_rate = 0;
return;
default:
p += command_len( *p );
}
}
}