gzdoom/game-music-emu/gme/Gym_Emu.cpp

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// Game_Music_Emu 0.6.0. http://www.slack.net/~ant/
#include "Gym_Emu.h"
#include "blargg_endian.h"
#include <string.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"
double const min_tempo = 0.25;
double const oversample_factor = 5 / 3.0;
double const fm_gain = 3.0;
const long base_clock = 53700300;
const long clock_rate = base_clock / 15;
Gym_Emu::Gym_Emu()
{
data = 0;
pos = 0;
set_type( gme_gym_type );
static const char* const names [] = {
"FM 1", "FM 2", "FM 3", "FM 4", "FM 5", "FM 6", "PCM", "PSG"
};
set_voice_names( names );
set_silence_lookahead( 1 ); // tracks should already be trimmed
}
Gym_Emu::~Gym_Emu() { }
// Track info
static void get_gym_info( Gym_Emu::header_t const& h, long length, track_info_t* out )
{
if ( !memcmp( h.tag, "GYMX", 4 ) )
{
length = length * 50 / 3; // 1000 / 60
long loop = get_le32( h.loop_start );
if ( loop )
{
out->intro_length = loop * 50 / 3;
out->loop_length = length - out->intro_length;
}
else
{
out->length = length;
out->intro_length = length; // make it clear that track is no longer than length
out->loop_length = 0;
}
// more stupidity where the field should have been left
if ( strcmp( h.song, "Unknown Song" ) )
GME_COPY_FIELD( h, out, song );
if ( strcmp( h.game, "Unknown Game" ) )
GME_COPY_FIELD( h, out, game );
if ( strcmp( h.copyright, "Unknown Publisher" ) )
GME_COPY_FIELD( h, out, copyright );
if ( strcmp( h.dumper, "Unknown Person" ) )
GME_COPY_FIELD( h, out, dumper );
if ( strcmp( h.comment, "Header added by YMAMP" ) )
GME_COPY_FIELD( h, out, comment );
}
}
blargg_err_t Gym_Emu::track_info_( track_info_t* out, int ) const
{
get_gym_info( header_, track_length(), out );
return 0;
}
static long gym_track_length( byte const* p, byte const* end )
{
long time = 0;
while ( p < end )
{
switch ( *p++ )
{
case 0:
time++;
break;
case 1:
case 2:
p += 2;
break;
case 3:
p += 1;
break;
}
}
return time;
}
long Gym_Emu::track_length() const { return gym_track_length( data, data_end ); }
static blargg_err_t check_header( byte const* in, long size, int* data_offset = 0 )
{
if ( size < 4 )
return gme_wrong_file_type;
if ( memcmp( in, "GYMX", 4 ) == 0 )
{
if ( size < Gym_Emu::header_size + 1 )
return gme_wrong_file_type;
if ( memcmp( ((Gym_Emu::header_t const*) in)->packed, "\0\0\0\0", 4 ) != 0 )
return "Packed GYM file not supported";
if ( data_offset )
*data_offset = Gym_Emu::header_size;
}
else if ( *in > 3 )
{
return gme_wrong_file_type;
}
return 0;
}
struct Gym_File : Gme_Info_
{
byte const* file_begin;
byte const* file_end;
int data_offset;
Gym_File() { set_type( gme_gym_type ); }
blargg_err_t load_mem_( byte const* in, long size )
{
file_begin = in;
file_end = in + size;
data_offset = 0;
return check_header( in, size, &data_offset );
}
blargg_err_t track_info_( track_info_t* out, int ) const
{
long length = gym_track_length( &file_begin [data_offset], file_end );
get_gym_info( *(Gym_Emu::header_t const*) file_begin, length, out );
return 0;
}
};
static Music_Emu* new_gym_emu () { return BLARGG_NEW Gym_Emu ; }
static Music_Emu* new_gym_file() { return BLARGG_NEW Gym_File; }
static gme_type_t_ const gme_gym_type_ = { "Sega Genesis", 1, &new_gym_emu, &new_gym_file, "GYM", 0 };
gme_type_t const gme_gym_type = &gme_gym_type_;
// Setup
blargg_err_t Gym_Emu::set_sample_rate_( long sample_rate )
{
blip_eq_t eq( -32, 8000, sample_rate );
apu.treble_eq( eq );
dac_synth.treble_eq( eq );
apu.volume( 0.135 * fm_gain * gain() );
dac_synth.volume( 0.125 / 256 * fm_gain * gain() );
double factor = Dual_Resampler::setup( oversample_factor, 0.990, fm_gain * gain() );
fm_sample_rate = sample_rate * factor;
RETURN_ERR( blip_buf.set_sample_rate( sample_rate, int (1000 / 60.0 / min_tempo) ) );
blip_buf.clock_rate( clock_rate );
RETURN_ERR( fm.set_rate( fm_sample_rate, base_clock / 7.0 ) );
RETURN_ERR( Dual_Resampler::reset( long (1.0 / 60 / min_tempo * sample_rate) ) );
return 0;
}
void Gym_Emu::set_tempo_( double t )
{
if ( t < min_tempo )
{
set_tempo( min_tempo );
return;
}
if ( blip_buf.sample_rate() )
{
clocks_per_frame = long (clock_rate / 60 / tempo());
Dual_Resampler::resize( long (sample_rate() / (60.0 * tempo())) );
}
}
void Gym_Emu::mute_voices_( int mask )
{
Music_Emu::mute_voices_( mask );
fm.mute_voices( mask );
dac_muted = (mask & 0x40) != 0;
apu.output( (mask & 0x80) ? 0 : &blip_buf );
}
blargg_err_t Gym_Emu::load_mem_( byte const* in, long size )
{
assert( offsetof (header_t,packed [4]) == header_size );
int offset = 0;
RETURN_ERR( check_header( in, size, &offset ) );
set_voice_count( 8 );
data = in + offset;
data_end = in + size;
loop_begin = 0;
if ( offset )
header_ = *(header_t const*) in;
else
memset( &header_, 0, sizeof header_ );
return 0;
}
// Emulation
blargg_err_t Gym_Emu::start_track_( int track )
{
RETURN_ERR( Music_Emu::start_track_( track ) );
pos = data;
loop_remain = get_le32( header_.loop_start );
prev_dac_count = 0;
dac_enabled = false;
dac_amp = -1;
fm.reset();
apu.reset();
blip_buf.clear();
Dual_Resampler::clear();
return 0;
}
void Gym_Emu::run_dac( int dac_count )
{
// Guess beginning and end of sample and adjust rate and buffer position accordingly.
// count dac samples in next frame
int next_dac_count = 0;
const byte* p = this->pos;
int cmd;
while ( (cmd = *p++) != 0 )
{
int data = *p++;
if ( cmd <= 2 )
++p;
if ( cmd == 1 && data == 0x2A )
next_dac_count++;
}
// detect beginning and end of sample
int rate_count = dac_count;
int start = 0;
if ( !prev_dac_count && next_dac_count && dac_count < next_dac_count )
{
rate_count = next_dac_count;
start = next_dac_count - dac_count;
}
else if ( prev_dac_count && !next_dac_count && dac_count < prev_dac_count )
{
rate_count = prev_dac_count;
}
// Evenly space samples within buffer section being used
blip_resampled_time_t period = blip_buf.resampled_duration( clocks_per_frame ) / rate_count;
blip_resampled_time_t time = blip_buf.resampled_time( 0 ) +
period * start + (period >> 1);
int dac_amp = this->dac_amp;
if ( dac_amp < 0 )
dac_amp = dac_buf [0];
for ( int i = 0; i < dac_count; i++ )
{
int delta = dac_buf [i] - dac_amp;
dac_amp += delta;
dac_synth.offset_resampled( time, delta, &blip_buf );
time += period;
}
this->dac_amp = dac_amp;
}
void Gym_Emu::parse_frame()
{
int dac_count = 0;
const byte* pos = this->pos;
if ( loop_remain && !--loop_remain )
loop_begin = pos; // find loop on first time through sequence
int cmd;
while ( (cmd = *pos++) != 0 )
{
int data = *pos++;
if ( cmd == 1 )
{
int data2 = *pos++;
if ( data != 0x2A )
{
if ( data == 0x2B )
dac_enabled = (data2 & 0x80) != 0;
fm.write0( data, data2 );
}
else if ( dac_count < (int) sizeof dac_buf )
{
dac_buf [dac_count] = data2;
dac_count += dac_enabled;
}
}
else if ( cmd == 2 )
{
fm.write1( data, *pos++ );
}
else if ( cmd == 3 )
{
apu.write_data( 0, data );
}
else
{
// to do: many GYM streams are full of errors, and error count should
// reflect cases where music is really having problems
//log_error();
--pos; // put data back
}
}
// loop
if ( pos >= data_end )
{
check( pos == data_end );
if ( loop_begin )
pos = loop_begin;
else
set_track_ended();
}
this->pos = pos;
// dac
if ( dac_count && !dac_muted )
run_dac( dac_count );
prev_dac_count = dac_count;
}
int Gym_Emu::play_frame( blip_time_t blip_time, int sample_count, sample_t* buf )
{
if ( !track_ended() )
parse_frame();
apu.end_frame( blip_time );
memset( buf, 0, sample_count * sizeof *buf );
fm.run( sample_count >> 1, buf );
return sample_count;
}
blargg_err_t Gym_Emu::play_( long count, sample_t* out )
{
Dual_Resampler::dual_play( count, out, blip_buf );
return 0;
}