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Diffstat (limited to 'plugins/gme/game-music-emu-svn/gme/Blip_Buffer.cpp')
| -rw-r--r-- | plugins/gme/game-music-emu-svn/gme/Blip_Buffer.cpp | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-svn/gme/Blip_Buffer.cpp b/plugins/gme/game-music-emu-svn/gme/Blip_Buffer.cpp new file mode 100644 index 00000000..2b88cd4f --- /dev/null +++ b/plugins/gme/game-music-emu-svn/gme/Blip_Buffer.cpp @@ -0,0 +1,460 @@ +// Blip_Buffer 0.4.1. http://www.slack.net/~ant/ + +#include "Blip_Buffer.h" + +#include <assert.h> +#include <limits.h> +#include <string.h> +#include <stdlib.h> +#include <math.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 */ + +#ifdef BLARGG_ENABLE_OPTIMIZER + #include BLARGG_ENABLE_OPTIMIZER +#endif + +int const silent_buf_size = 1; // size used for Silent_Blip_Buffer + +Blip_Buffer::Blip_Buffer() +{ + factor_ = (blip_ulong)-1 / 2; + offset_ = 0; + buffer_ = 0; + buffer_size_ = 0; + sample_rate_ = 0; + reader_accum_ = 0; + bass_shift_ = 0; + clock_rate_ = 0; + bass_freq_ = 16; + length_ = 0; + + // assumptions code makes about implementation-defined features + #ifndef NDEBUG + // right shift of negative value preserves sign + buf_t_ i = -0x7FFFFFFE; + assert( (i >> 1) == -0x3FFFFFFF ); + + // casting to short truncates to 16 bits and sign-extends + i = 0x18000; + assert( (short) i == -0x8000 ); + #endif +} + +Blip_Buffer::~Blip_Buffer() +{ + if ( buffer_size_ != silent_buf_size ) + free( buffer_ ); +} + +Silent_Blip_Buffer::Silent_Blip_Buffer() +{ + factor_ = 0; + buffer_ = buf; + buffer_size_ = silent_buf_size; + memset( buf, 0, sizeof buf ); // in case machine takes exception for signed overflow +} + +void Blip_Buffer::clear( int entire_buffer ) +{ + offset_ = 0; + reader_accum_ = 0; + modified_ = 0; + if ( buffer_ ) + { + long count = (entire_buffer ? buffer_size_ : samples_avail()); + memset( buffer_, 0, (count + blip_buffer_extra_) * sizeof (buf_t_) ); + } +} + +Blip_Buffer::blargg_err_t Blip_Buffer::set_sample_rate( long new_rate, int msec ) +{ + if ( buffer_size_ == silent_buf_size ) + { + assert( 0 ); + return "Internal (tried to resize Silent_Blip_Buffer)"; + } + + // start with maximum length that resampled time can represent + long new_size = (UINT_MAX >> BLIP_BUFFER_ACCURACY) - blip_buffer_extra_ - 64; + if ( msec != blip_max_length ) + { + long s = (new_rate * (msec + 1) + 999) / 1000; + if ( s < new_size ) + new_size = s; + else + assert( 0 ); // fails if requested buffer length exceeds limit + } + + if ( buffer_size_ != new_size ) + { + void* p = realloc( buffer_, (new_size + blip_buffer_extra_) * sizeof *buffer_ ); + if ( !p ) + return "Out of memory"; + buffer_ = (buf_t_*) p; + } + + buffer_size_ = new_size; + assert( buffer_size_ != silent_buf_size ); + + // update things based on the sample rate + sample_rate_ = new_rate; + length_ = new_size * 1000 / new_rate - 1; + if ( msec ) + assert( length_ == msec ); // ensure length is same as that passed in + if ( clock_rate_ ) + clock_rate( clock_rate_ ); + bass_freq( bass_freq_ ); + + clear(); + + return 0; // success +} + +blip_resampled_time_t Blip_Buffer::clock_rate_factor( long rate ) const +{ + double ratio = (double) sample_rate_ / rate; + blip_long factor = (blip_long) floor( ratio * (1L << BLIP_BUFFER_ACCURACY) + 0.5 ); + assert( factor > 0 || !sample_rate_ ); // fails if clock/output ratio is too large + return (blip_resampled_time_t) factor; +} + +void Blip_Buffer::bass_freq( int freq ) +{ + bass_freq_ = freq; + int shift = 31; + if ( freq > 0 ) + { + shift = 13; + long f = (freq << 16) / sample_rate_; + while ( (f >>= 1) && --shift ) { } + } + bass_shift_ = shift; +} + +void Blip_Buffer::end_frame( blip_time_t t ) +{ + offset_ += t * factor_; + assert( samples_avail() <= (long) buffer_size_ ); // time outside buffer length +} + +void Blip_Buffer::remove_silence( long count ) +{ + assert( count <= samples_avail() ); // tried to remove more samples than available + offset_ -= (blip_resampled_time_t) count << BLIP_BUFFER_ACCURACY; +} + +long Blip_Buffer::count_samples( blip_time_t t ) const +{ + unsigned long last_sample = resampled_time( t ) >> BLIP_BUFFER_ACCURACY; + unsigned long first_sample = offset_ >> BLIP_BUFFER_ACCURACY; + return (long) (last_sample - first_sample); +} + +blip_time_t Blip_Buffer::count_clocks( long count ) const +{ + if ( !factor_ ) + { + assert( 0 ); // sample rate and clock rates must be set first + return 0; + } + + if ( count > buffer_size_ ) + count = buffer_size_; + blip_resampled_time_t time = (blip_resampled_time_t) count << BLIP_BUFFER_ACCURACY; + return (blip_time_t) ((time - offset_ + factor_ - 1) / factor_); +} + +void Blip_Buffer::remove_samples( long count ) +{ + if ( count ) + { + remove_silence( count ); + + // copy remaining samples to beginning and clear old samples + long remain = samples_avail() + blip_buffer_extra_; + memmove( buffer_, buffer_ + count, remain * sizeof *buffer_ ); + memset( buffer_ + remain, 0, count * sizeof *buffer_ ); + } +} + +// Blip_Synth_ + +Blip_Synth_Fast_::Blip_Synth_Fast_() +{ + buf = 0; + last_amp = 0; + delta_factor = 0; +} + +void Blip_Synth_Fast_::volume_unit( double new_unit ) +{ + delta_factor = int (new_unit * (1L << blip_sample_bits) + 0.5); +} + +#if !BLIP_BUFFER_FAST + +Blip_Synth_::Blip_Synth_( short* p, int w ) : + impulses( p ), + width( w ) +{ + volume_unit_ = 0.0; + kernel_unit = 0; + buf = 0; + last_amp = 0; + delta_factor = 0; +} + +#undef PI +#define PI 3.1415926535897932384626433832795029 + +static void gen_sinc( float* out, int count, double oversample, double treble, double cutoff ) +{ + if ( cutoff >= 0.999 ) + cutoff = 0.999; + + if ( treble < -300.0 ) + treble = -300.0; + if ( treble > 5.0 ) + treble = 5.0; + + double const maxh = 4096.0; + double const rolloff = pow( 10.0, 1.0 / (maxh * 20.0) * treble / (1.0 - cutoff) ); + double const pow_a_n = pow( rolloff, maxh - maxh * cutoff ); + double const to_angle = PI / 2 / maxh / oversample; + for ( int i = 0; i < count; i++ ) + { + double angle = ((i - count) * 2 + 1) * to_angle; + double angle_maxh = angle * maxh; + double angle_maxh_mid = angle_maxh * cutoff; + + double y = maxh; + + // 0 to Fs/2*cutoff, flat + if ( angle_maxh_mid ) // unstable at t=0 + y *= sin( angle_maxh_mid ) / angle_maxh_mid; + + // Fs/2*cutoff to Fs/2, logarithmic rolloff + double cosa = cos( angle ); + double den = 1 + rolloff * (rolloff - cosa - cosa); + + // Becomes unstable when rolloff is near 1.0 and t is near 0, + // which is the only time den becomes small + if ( den > 1e-13 ) + { + double num = + (cos( angle_maxh - angle ) * rolloff - cos( angle_maxh )) * pow_a_n - + cos( angle_maxh_mid - angle ) * rolloff + cos( angle_maxh_mid ); + + y = y * cutoff + num / den; + } + + out [i] = (float) y; + } +} + +void blip_eq_t::generate( float* out, int count ) const +{ + // lower cutoff freq for narrow kernels with their wider transition band + // (8 points->1.49, 16 points->1.15) + double oversample = blip_res * 2.25 / count + 0.85; + double half_rate = sample_rate * 0.5; + if ( cutoff_freq ) + oversample = half_rate / cutoff_freq; + double cutoff = rolloff_freq * oversample / half_rate; + + gen_sinc( out, count, blip_res * oversample, treble, cutoff ); + + // apply (half of) hamming window + double to_fraction = PI / (count - 1); + for ( int i = count; i--; ) + out [i] *= 0.54f - 0.46f * (float) cos( i * to_fraction ); +} + +void Blip_Synth_::adjust_impulse() +{ + // sum pairs for each phase and add error correction to end of first half + int const size = impulses_size(); + for ( int p = blip_res; p-- >= blip_res / 2; ) + { + int p2 = blip_res - 2 - p; + long error = kernel_unit; + for ( int i = 1; i < size; i += blip_res ) + { + error -= impulses [i + p ]; + error -= impulses [i + p2]; + } + if ( p == p2 ) + error /= 2; // phase = 0.5 impulse uses same half for both sides + impulses [size - blip_res + p] += (short) error; + //printf( "error: %ld\n", error ); + } + + //for ( int i = blip_res; i--; printf( "\n" ) ) + // for ( int j = 0; j < width / 2; j++ ) + // printf( "%5ld,", impulses [j * blip_res + i + 1] ); +} + +void Blip_Synth_::treble_eq( blip_eq_t const& eq ) +{ + float fimpulse [blip_res / 2 * (blip_widest_impulse_ - 1) + blip_res * 2]; + + int const half_size = blip_res / 2 * (width - 1); + eq.generate( &fimpulse [blip_res], half_size ); + + int i; + + // need mirror slightly past center for calculation + for ( i = blip_res; i--; ) + fimpulse [blip_res + half_size + i] = fimpulse [blip_res + half_size - 1 - i]; + + // starts at 0 + for ( i = 0; i < blip_res; i++ ) + fimpulse [i] = 0.0f; + + // find rescale factor + double total = 0.0; + for ( i = 0; i < half_size; i++ ) + total += fimpulse [blip_res + i]; + + //double const base_unit = 44800.0 - 128 * 18; // allows treble up to +0 dB + //double const base_unit = 37888.0; // allows treble to +5 dB + double const base_unit = 32768.0; // necessary for blip_unscaled to work + double rescale = base_unit / 2 / total; + kernel_unit = (long) base_unit; + + // integrate, first difference, rescale, convert to int + double sum = 0.0; + double next = 0.0; + int const impulses_size = this->impulses_size(); + for ( i = 0; i < impulses_size; i++ ) + { + impulses [i] = (short) floor( (next - sum) * rescale + 0.5 ); + sum += fimpulse [i]; + next += fimpulse [i + blip_res]; + } + adjust_impulse(); + + // volume might require rescaling + double vol = volume_unit_; + if ( vol ) + { + volume_unit_ = 0.0; + volume_unit( vol ); + } +} + +void Blip_Synth_::volume_unit( double new_unit ) +{ + if ( new_unit != volume_unit_ ) + { + // use default eq if it hasn't been set yet + if ( !kernel_unit ) + treble_eq( -8.0 ); + + volume_unit_ = new_unit; + double factor = new_unit * (1L << blip_sample_bits) / kernel_unit; + + if ( factor > 0.0 ) + { + int shift = 0; + + // if unit is really small, might need to attenuate kernel + while ( factor < 2.0 ) + { + shift++; + factor *= 2.0; + } + + if ( shift ) + { + kernel_unit >>= shift; + assert( kernel_unit > 0 ); // fails if volume unit is too low + + // keep values positive to avoid round-towards-zero of sign-preserving + // right shift for negative values + long offset = 0x8000 + (1 << (shift - 1)); + long offset2 = 0x8000 >> shift; + for ( int i = impulses_size(); i--; ) + impulses [i] = (short) (((impulses [i] + offset) >> shift) - offset2); + adjust_impulse(); + } + } + delta_factor = (int) floor( factor + 0.5 ); + //printf( "delta_factor: %d, kernel_unit: %d\n", delta_factor, kernel_unit ); + } +} +#endif + +long Blip_Buffer::read_samples( blip_sample_t* BLIP_RESTRICT out, long max_samples, int stereo ) +{ + long count = samples_avail(); + if ( count > max_samples ) + count = max_samples; + + if ( count ) + { + int const bass = BLIP_READER_BASS( *this ); + BLIP_READER_BEGIN( reader, *this ); + + if ( !stereo ) + { + for ( blip_long n = count; n; --n ) + { + blip_long s = BLIP_READER_READ( reader ); + if ( (blip_sample_t) s != s ) + s = 0x7FFF - (s >> 24); + *out++ = (blip_sample_t) s; + BLIP_READER_NEXT( reader, bass ); + } + } + else + { + for ( blip_long n = count; n; --n ) + { + blip_long s = BLIP_READER_READ( reader ); + if ( (blip_sample_t) s != s ) + s = 0x7FFF - (s >> 24); + *out = (blip_sample_t) s; + out += 2; + BLIP_READER_NEXT( reader, bass ); + } + } + BLIP_READER_END( reader, *this ); + + remove_samples( count ); + } + return count; +} + +void Blip_Buffer::mix_samples( blip_sample_t const* in, long count ) +{ + if ( buffer_size_ == silent_buf_size ) + { + assert( 0 ); + return; + } + + buf_t_* out = buffer_ + (offset_ >> BLIP_BUFFER_ACCURACY) + blip_widest_impulse_ / 2; + + int const sample_shift = blip_sample_bits - 16; + int prev = 0; + while ( count-- ) + { + blip_long s = (blip_long) *in++ << sample_shift; + *out += s - prev; + prev = s; + ++out; + } + *out -= prev; +} + |