diff options
Diffstat (limited to 'plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Namco_Apu.cpp')
| -rw-r--r-- | plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Namco_Apu.cpp | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Namco_Apu.cpp b/plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Namco_Apu.cpp new file mode 100644 index 00000000..f3235b38 --- /dev/null +++ b/plugins/gme/Game_Music_Emu-0.5.2/gme/Nes_Namco_Apu.cpp @@ -0,0 +1,145 @@ +// Nes_Snd_Emu 0.1.8. http://www.slack.net/~ant/ + +#include "Nes_Namco_Apu.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" + +Nes_Namco_Apu::Nes_Namco_Apu() +{ + output( NULL ); + volume( 1.0 ); + reset(); +} + +void Nes_Namco_Apu::reset() +{ + last_time = 0; + addr_reg = 0; + + int i; + for ( i = 0; i < reg_count; i++ ) + reg [i] = 0; + + for ( i = 0; i < osc_count; i++ ) + { + Namco_Osc& osc = oscs [i]; + osc.delay = 0; + osc.last_amp = 0; + osc.wave_pos = 0; + } +} + +void Nes_Namco_Apu::output( Blip_Buffer* buf ) +{ + for ( int i = 0; i < osc_count; i++ ) + osc_output( i, buf ); +} + +/* +void Nes_Namco_Apu::reflect_state( Tagged_Data& data ) +{ + reflect_int16( data, BLARGG_4CHAR('A','D','D','R'), &addr_reg ); + + static const char hex [17] = "0123456789ABCDEF"; + int i; + for ( i = 0; i < reg_count; i++ ) + reflect_int16( data, 'RG\0\0' + hex [i >> 4] * 0x100 + hex [i & 15], ® [i] ); + + for ( i = 0; i < osc_count; i++ ) + { + reflect_int32( data, BLARGG_4CHAR('D','L','Y','0') + i, &oscs [i].delay ); + reflect_int16( data, BLARGG_4CHAR('P','O','S','0') + i, &oscs [i].wave_pos ); + } +} +*/ + +void Nes_Namco_Apu::end_frame( blip_time_t time ) +{ + if ( time > last_time ) + run_until( time ); + + assert( last_time >= time ); + last_time -= time; +} + +void Nes_Namco_Apu::run_until( blip_time_t nes_end_time ) +{ + int active_oscs = (reg [0x7F] >> 4 & 7) + 1; + for ( int i = osc_count - active_oscs; i < osc_count; i++ ) + { + Namco_Osc& osc = oscs [i]; + Blip_Buffer* output = osc.output; + if ( !output ) + continue; + output->set_modified(); + + blip_resampled_time_t time = + output->resampled_time( last_time ) + osc.delay; + blip_resampled_time_t end_time = output->resampled_time( nes_end_time ); + osc.delay = 0; + if ( time < end_time ) + { + const BOOST::uint8_t* osc_reg = ® [i * 8 + 0x40]; + if ( !(osc_reg [4] & 0xE0) ) + continue; + + int volume = osc_reg [7] & 15; + if ( !volume ) + continue; + + blargg_long freq = (osc_reg [4] & 3) * 0x10000 + osc_reg [2] * 0x100L + osc_reg [0]; + if ( freq < 64 * active_oscs ) + continue; // prevent low frequencies from excessively delaying freq changes + blip_resampled_time_t period = + output->resampled_duration( 983040 ) / freq * active_oscs; + + int wave_size = 32 - (osc_reg [4] >> 2 & 7) * 4; + if ( !wave_size ) + continue; + + int last_amp = osc.last_amp; + int wave_pos = osc.wave_pos; + + do + { + // read wave sample + int addr = wave_pos + osc_reg [6]; + int sample = reg [addr >> 1] >> (addr << 2 & 4); + wave_pos++; + sample = (sample & 15) * volume; + + // output impulse if amplitude changed + int delta = sample - last_amp; + if ( delta ) + { + last_amp = sample; + synth.offset_resampled( time, delta, output ); + } + + // next sample + time += period; + if ( wave_pos >= wave_size ) + wave_pos = 0; + } + while ( time < end_time ); + + osc.wave_pos = wave_pos; + osc.last_amp = last_amp; + } + osc.delay = time - end_time; + } + + last_time = nes_end_time; +} + |