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380 lines
8.6 KiB
C++
380 lines
8.6 KiB
C++
// Game_Music_Emu 0.6.0. http://www.slack.net/~ant/
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#include "Gym_Emu.h"
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#include "blargg_endian.h"
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#include <string.h>
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/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "blargg_source.h"
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double const min_tempo = 0.25;
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double const oversample_factor = 5 / 3.0;
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double const fm_gain = 3.0;
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const long base_clock = 53700300;
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const long clock_rate = base_clock / 15;
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Gym_Emu::Gym_Emu()
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{
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data = 0;
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pos = 0;
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set_type( gme_gym_type );
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static const char* const names [] = {
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"FM 1", "FM 2", "FM 3", "FM 4", "FM 5", "FM 6", "PCM", "PSG"
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};
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set_voice_names( names );
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set_silence_lookahead( 1 ); // tracks should already be trimmed
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}
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Gym_Emu::~Gym_Emu() { }
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// Track info
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static void get_gym_info( Gym_Emu::header_t const& h, long length, track_info_t* out )
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{
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if ( !memcmp( h.tag, "GYMX", 4 ) )
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{
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length = length * 50 / 3; // 1000 / 60
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long loop = get_le32( h.loop_start );
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if ( loop )
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{
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out->intro_length = loop * 50 / 3;
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out->loop_length = length - out->intro_length;
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}
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else
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{
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out->length = length;
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out->intro_length = length; // make it clear that track is no longer than length
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out->loop_length = 0;
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}
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// more stupidity where the field should have been left
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if ( strcmp( h.song, "Unknown Song" ) )
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GME_COPY_FIELD( h, out, song );
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if ( strcmp( h.game, "Unknown Game" ) )
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GME_COPY_FIELD( h, out, game );
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if ( strcmp( h.copyright, "Unknown Publisher" ) )
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GME_COPY_FIELD( h, out, copyright );
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if ( strcmp( h.dumper, "Unknown Person" ) )
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GME_COPY_FIELD( h, out, dumper );
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if ( strcmp( h.comment, "Header added by YMAMP" ) )
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GME_COPY_FIELD( h, out, comment );
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}
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}
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blargg_err_t Gym_Emu::track_info_( track_info_t* out, int ) const
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{
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get_gym_info( header_, track_length(), out );
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return 0;
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}
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static long gym_track_length( byte const* p, byte const* end )
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{
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long time = 0;
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while ( p < end )
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{
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switch ( *p++ )
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{
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case 0:
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time++;
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break;
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case 1:
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case 2:
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p += 2;
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break;
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case 3:
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p += 1;
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break;
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}
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}
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return time;
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}
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long Gym_Emu::track_length() const { return gym_track_length( data, data_end ); }
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static blargg_err_t check_header( byte const* in, long size, int* data_offset = 0 )
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{
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if ( size < 4 )
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return gme_wrong_file_type;
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if ( memcmp( in, "GYMX", 4 ) == 0 )
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{
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if ( size < Gym_Emu::header_size + 1 )
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return gme_wrong_file_type;
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if ( memcmp( ((Gym_Emu::header_t const*) in)->packed, "\0\0\0\0", 4 ) != 0 )
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return "Packed GYM file not supported";
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if ( data_offset )
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*data_offset = Gym_Emu::header_size;
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}
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else if ( *in > 3 )
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{
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return gme_wrong_file_type;
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}
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return 0;
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}
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struct Gym_File : Gme_Info_
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{
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byte const* file_begin;
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byte const* file_end;
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int data_offset;
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Gym_File() { set_type( gme_gym_type ); }
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blargg_err_t load_mem_( byte const* in, long size )
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{
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file_begin = in;
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file_end = in + size;
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data_offset = 0;
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return check_header( in, size, &data_offset );
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}
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blargg_err_t track_info_( track_info_t* out, int ) const
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{
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long length = gym_track_length( &file_begin [data_offset], file_end );
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get_gym_info( *(Gym_Emu::header_t const*) file_begin, length, out );
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return 0;
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}
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};
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static Music_Emu* new_gym_emu () { return BLARGG_NEW Gym_Emu ; }
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static Music_Emu* new_gym_file() { return BLARGG_NEW Gym_File; }
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static gme_type_t_ const gme_gym_type_ = { "Sega Genesis", 1, &new_gym_emu, &new_gym_file, "GYM", 0 };
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gme_type_t const gme_gym_type = &gme_gym_type_;
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// Setup
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blargg_err_t Gym_Emu::set_sample_rate_( long sample_rate )
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{
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blip_eq_t eq( -32, 8000, sample_rate );
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apu.treble_eq( eq );
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dac_synth.treble_eq( eq );
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apu.volume( 0.135 * fm_gain * gain() );
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dac_synth.volume( 0.125 / 256 * fm_gain * gain() );
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double factor = Dual_Resampler::setup( oversample_factor, 0.990, fm_gain * gain() );
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fm_sample_rate = sample_rate * factor;
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RETURN_ERR( blip_buf.set_sample_rate( sample_rate, int (1000 / 60.0 / min_tempo) ) );
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blip_buf.clock_rate( clock_rate );
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RETURN_ERR( fm.set_rate( fm_sample_rate, base_clock / 7.0 ) );
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RETURN_ERR( Dual_Resampler::reset( long (1.0 / 60 / min_tempo * sample_rate) ) );
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return 0;
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}
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void Gym_Emu::set_tempo_( double t )
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{
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if ( t < min_tempo )
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{
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set_tempo( min_tempo );
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return;
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}
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if ( blip_buf.sample_rate() )
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{
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clocks_per_frame = long (clock_rate / 60 / tempo());
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Dual_Resampler::resize( long (sample_rate() / (60.0 * tempo())) );
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}
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}
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void Gym_Emu::mute_voices_( int mask )
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{
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Music_Emu::mute_voices_( mask );
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fm.mute_voices( mask );
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dac_muted = (mask & 0x40) != 0;
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apu.output( (mask & 0x80) ? 0 : &blip_buf );
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}
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blargg_err_t Gym_Emu::load_mem_( byte const* in, long size )
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{
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assert( offsetof (header_t,packed [4]) == header_size );
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int offset = 0;
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RETURN_ERR( check_header( in, size, &offset ) );
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set_voice_count( 8 );
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data = in + offset;
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data_end = in + size;
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loop_begin = 0;
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if ( offset )
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header_ = *(header_t const*) in;
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else
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memset( &header_, 0, sizeof header_ );
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return 0;
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}
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// Emulation
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blargg_err_t Gym_Emu::start_track_( int track )
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{
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RETURN_ERR( Music_Emu::start_track_( track ) );
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pos = data;
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loop_remain = get_le32( header_.loop_start );
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prev_dac_count = 0;
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dac_enabled = false;
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dac_amp = -1;
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fm.reset();
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apu.reset();
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blip_buf.clear();
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Dual_Resampler::clear();
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return 0;
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}
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void Gym_Emu::run_dac( int dac_count )
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{
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// Guess beginning and end of sample and adjust rate and buffer position accordingly.
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// count dac samples in next frame
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int next_dac_count = 0;
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const byte* p = this->pos;
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int cmd;
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while ( (cmd = *p++) != 0 )
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{
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int data = *p++;
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if ( cmd <= 2 )
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++p;
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if ( cmd == 1 && data == 0x2A )
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next_dac_count++;
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}
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// detect beginning and end of sample
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int rate_count = dac_count;
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int start = 0;
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if ( !prev_dac_count && next_dac_count && dac_count < next_dac_count )
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{
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rate_count = next_dac_count;
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start = next_dac_count - dac_count;
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}
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else if ( prev_dac_count && !next_dac_count && dac_count < prev_dac_count )
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{
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rate_count = prev_dac_count;
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}
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// Evenly space samples within buffer section being used
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blip_resampled_time_t period = blip_buf.resampled_duration( clocks_per_frame ) / rate_count;
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blip_resampled_time_t time = blip_buf.resampled_time( 0 ) +
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period * start + (period >> 1);
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int dac_amp = this->dac_amp;
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if ( dac_amp < 0 )
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dac_amp = dac_buf [0];
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for ( int i = 0; i < dac_count; i++ )
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{
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int delta = dac_buf [i] - dac_amp;
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dac_amp += delta;
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dac_synth.offset_resampled( time, delta, &blip_buf );
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time += period;
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}
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this->dac_amp = dac_amp;
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}
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void Gym_Emu::parse_frame()
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{
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int dac_count = 0;
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const byte* pos = this->pos;
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if ( loop_remain && !--loop_remain )
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loop_begin = pos; // find loop on first time through sequence
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int cmd;
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while ( (cmd = *pos++) != 0 )
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{
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int data = *pos++;
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if ( cmd == 1 )
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{
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int data2 = *pos++;
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if ( data != 0x2A )
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{
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if ( data == 0x2B )
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dac_enabled = (data2 & 0x80) != 0;
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fm.write0( data, data2 );
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}
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else if ( dac_count < (int) sizeof dac_buf )
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{
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dac_buf [dac_count] = data2;
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dac_count += dac_enabled;
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}
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}
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else if ( cmd == 2 )
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{
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fm.write1( data, *pos++ );
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}
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else if ( cmd == 3 )
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{
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apu.write_data( 0, data );
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}
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else
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{
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// to do: many GYM streams are full of errors, and error count should
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// reflect cases where music is really having problems
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//log_error();
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--pos; // put data back
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}
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}
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// loop
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if ( pos >= data_end )
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{
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check( pos == data_end );
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if ( loop_begin )
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pos = loop_begin;
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else
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set_track_ended();
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}
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this->pos = pos;
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// dac
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if ( dac_count && !dac_muted )
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run_dac( dac_count );
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prev_dac_count = dac_count;
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}
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int Gym_Emu::play_frame( blip_time_t blip_time, int sample_count, sample_t* buf )
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{
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if ( !track_ended() )
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parse_frame();
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apu.end_frame( blip_time );
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memset( buf, 0, sample_count * sizeof *buf );
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fm.run( sample_count >> 1, buf );
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return sample_count;
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}
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blargg_err_t Gym_Emu::play_( long count, sample_t* out )
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{
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Dual_Resampler::dual_play( count, out, blip_buf );
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return 0;
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}
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