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131 lines
3.5 KiB
C++
131 lines
3.5 KiB
C++
// Game_Music_Emu 0.5.2. http://www.slack.net/~ant/
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#include "Dual_Resampler.h"
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#include <stdlib.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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unsigned const resampler_extra = 256;
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Dual_Resampler::Dual_Resampler() { }
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Dual_Resampler::~Dual_Resampler() { }
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blargg_err_t Dual_Resampler::reset( int pairs )
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{
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// expand allocations a bit
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RETURN_ERR( sample_buf.resize( (pairs + (pairs >> 2)) * 2 ) );
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resize( pairs );
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resampler_size = oversamples_per_frame + (oversamples_per_frame >> 2);
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return resampler.buffer_size( resampler_size );
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}
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void Dual_Resampler::resize( int pairs )
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{
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int new_sample_buf_size = pairs * 2;
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if ( sample_buf_size != new_sample_buf_size )
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{
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if ( (unsigned) new_sample_buf_size > sample_buf.size() )
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{
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check( false );
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return;
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}
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sample_buf_size = new_sample_buf_size;
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oversamples_per_frame = int (pairs * resampler.ratio()) * 2 + 2;
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clear();
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}
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}
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void Dual_Resampler::play_frame_( Blip_Buffer& blip_buf, dsample_t* out )
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{
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long pair_count = sample_buf_size >> 1;
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blip_time_t blip_time = blip_buf.count_clocks( pair_count );
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int sample_count = oversamples_per_frame - resampler.written();
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int new_count = play_frame( blip_time, sample_count, resampler.buffer() );
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assert( new_count < resampler_size );
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blip_buf.end_frame( blip_time );
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assert( blip_buf.samples_avail() == pair_count );
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resampler.write( new_count );
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long count = resampler.read( sample_buf.begin(), sample_buf_size );
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assert( count == (long) sample_buf_size );
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mix_samples( blip_buf, out );
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blip_buf.remove_samples( pair_count );
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}
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void Dual_Resampler::dual_play( long count, dsample_t* out, Blip_Buffer& blip_buf )
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{
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// empty extra buffer
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long remain = sample_buf_size - buf_pos;
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if ( remain )
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{
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if ( remain > count )
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remain = count;
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count -= remain;
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memcpy( out, &sample_buf [buf_pos], remain * sizeof *out );
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out += remain;
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buf_pos += remain;
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}
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// entire frames
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while ( count >= (long) sample_buf_size )
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{
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play_frame_( blip_buf, out );
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out += sample_buf_size;
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count -= sample_buf_size;
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}
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// extra
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if ( count )
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{
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play_frame_( blip_buf, sample_buf.begin() );
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buf_pos = count;
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memcpy( out, sample_buf.begin(), count * sizeof *out );
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out += count;
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}
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}
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void Dual_Resampler::mix_samples( Blip_Buffer& blip_buf, dsample_t* out )
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{
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Blip_Reader sn;
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int bass = sn.begin( blip_buf );
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const dsample_t* in = sample_buf.begin();
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for ( int n = sample_buf_size >> 1; n--; )
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{
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int s = sn.read();
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blargg_long l = (blargg_long) in [0] * 2 + s;
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if ( (BOOST::int16_t) l != l )
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l = 0x7FFF - (l >> 24);
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sn.next( bass );
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blargg_long r = (blargg_long) in [1] * 2 + s;
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if ( (BOOST::int16_t) r != r )
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r = 0x7FFF - (r >> 24);
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in += 2;
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out [0] = l;
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out [1] = r;
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out += 2;
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}
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sn.end( blip_buf );
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}
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