raze-gles/libraries/game-music-emu/gme/Dual_Resampler.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

141 lines
3.7 KiB
C++

// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#include "Dual_Resampler.h"
#include <stdlib.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"
unsigned const resampler_extra = 256;
Dual_Resampler::Dual_Resampler() :
sample_buf_size(0),
oversamples_per_frame(-1),
buf_pos(-1),
resampler_size(0)
{
}
Dual_Resampler::~Dual_Resampler() { }
blargg_err_t Dual_Resampler::reset( int pairs )
{
// expand allocations a bit
RETURN_ERR( sample_buf.resize( (pairs + (pairs >> 2)) * 2 ) );
resize( pairs );
resampler_size = oversamples_per_frame + (oversamples_per_frame >> 2);
return resampler.buffer_size( resampler_size );
}
void Dual_Resampler::resize( int pairs )
{
int new_sample_buf_size = pairs * 2;
if ( sample_buf_size != new_sample_buf_size )
{
if ( (unsigned) new_sample_buf_size > sample_buf.size() )
{
check( false );
return;
}
sample_buf_size = new_sample_buf_size;
oversamples_per_frame = int (pairs * resampler.ratio()) * 2 + 2;
clear();
}
}
void Dual_Resampler::play_frame_( Blip_Buffer& blip_buf, dsample_t* out )
{
long pair_count = sample_buf_size >> 1;
blip_time_t blip_time = blip_buf.count_clocks( pair_count );
int sample_count = oversamples_per_frame - resampler.written();
int new_count = play_frame( blip_time, sample_count, resampler.buffer() );
assert( new_count < resampler_size );
blip_buf.end_frame( blip_time );
assert( blip_buf.samples_avail() == pair_count );
resampler.write( new_count );
#ifdef NDEBUG // Avoid warning when asserts are disabled
resampler.read( sample_buf.begin(), sample_buf_size );
#else
long count = resampler.read( sample_buf.begin(), sample_buf_size );
assert( count == (long) sample_buf_size );
#endif
mix_samples( blip_buf, out );
blip_buf.remove_samples( pair_count );
}
void Dual_Resampler::dual_play( long count, dsample_t* out, Blip_Buffer& blip_buf )
{
// empty extra buffer
long remain = sample_buf_size - buf_pos;
if ( remain )
{
if ( remain > count )
remain = count;
count -= remain;
memcpy( out, &sample_buf [buf_pos], remain * sizeof *out );
out += remain;
buf_pos += remain;
}
// entire frames
while ( count >= (long) sample_buf_size )
{
play_frame_( blip_buf, out );
out += sample_buf_size;
count -= sample_buf_size;
}
// extra
if ( count )
{
play_frame_( blip_buf, sample_buf.begin() );
buf_pos = count;
memcpy( out, sample_buf.begin(), count * sizeof *out );
out += count;
}
}
void Dual_Resampler::mix_samples( Blip_Buffer& blip_buf, dsample_t* out )
{
Blip_Reader sn;
int bass = sn.begin( blip_buf );
const dsample_t* in = sample_buf.begin();
for ( int n = sample_buf_size >> 1; n--; )
{
int s = sn.read();
blargg_long l = (blargg_long) in [0] * 2 + s;
if ( (int16_t) l != l )
l = 0x7FFF - (l >> 24);
sn.next( bass );
blargg_long r = (blargg_long) in [1] * 2 + s;
if ( (int16_t) r != r )
r = 0x7FFF - (r >> 24);
in += 2;
out [0] = l;
out [1] = r;
out += 2;
}
sn.end( blip_buf );
}