diff options
Diffstat (limited to 'plugins/gme/game-music-emu-0.6pre/gme/Blip_Buffer.cpp')
| -rw-r--r-- | plugins/gme/game-music-emu-0.6pre/gme/Blip_Buffer.cpp | 509 |
1 files changed, 509 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6pre/gme/Blip_Buffer.cpp b/plugins/gme/game-music-emu-0.6pre/gme/Blip_Buffer.cpp new file mode 100644 index 00000000..97166297 --- /dev/null +++ b/plugins/gme/game-music-emu-0.6pre/gme/Blip_Buffer.cpp @@ -0,0 +1,509 @@ +// Blip_Buffer 0.4.0. http://www.slack.net/~ant/
+
+#include "Blip_Buffer.h"
+
+#include <math.h>
+
+/* Copyright (C) 2003-2008 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"
+
+//// Blip_Buffer
+
+Blip_Buffer::Blip_Buffer()
+{
+ factor_ = UINT_MAX/2 + 1;
+ buffer_ = NULL;
+ buffer_center_ = NULL;
+ buffer_size_ = 0;
+ sample_rate_ = 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
+ int i = -0x7FFFFFFE;
+ assert( (i >> 1) == -0x3FFFFFFF );
+
+ // casting truncates and sign-extends
+ i = 0x18000;
+ assert( (BOOST::int16_t) i == -0x8000 );
+ #endif
+
+ clear();
+}
+
+Blip_Buffer::~Blip_Buffer()
+{
+ free( buffer_ );
+}
+
+void Blip_Buffer::clear()
+{
+ bool const entire_buffer = true;
+
+ offset_ = 0;
+ reader_accum_ = 0;
+ modified_ = false;
+
+ if ( buffer_ )
+ {
+ int count = (entire_buffer ? buffer_size_ : samples_avail());
+ memset( buffer_, 0, (count + blip_buffer_extra_) * sizeof (delta_t) );
+ }
+}
+
+blargg_err_t Blip_Buffer::set_sample_rate( int new_rate, int msec )
+{
+ // Limit to maximum size that resampled time can represent
+ int max_size = (((blip_resampled_time_t) -1) >> BLIP_BUFFER_ACCURACY) -
+ blip_buffer_extra_ - 64; // TODO: -64 isn't needed
+ int new_size = (new_rate * (msec + 1) + 999) / 1000;
+ if ( new_size > max_size )
+ new_size = max_size;
+
+ // Resize buffer
+ if ( buffer_size_ != new_size )
+ {
+ //dprintf( "%d \n", (new_size + blip_buffer_extra_) * sizeof *buffer_ );
+ void* p = realloc( buffer_, (new_size + blip_buffer_extra_) * sizeof *buffer_ );
+ CHECK_ALLOC( p );
+ buffer_ = (delta_t*) p;
+ buffer_center_ = buffer_ + BLIP_MAX_QUALITY/2;
+ buffer_size_ = new_size;
+ }
+
+ // Update sample_rate and things that depend on it
+ sample_rate_ = new_rate;
+ length_ = new_size * 1000 / new_rate - 1;
+ if ( clock_rate_ )
+ clock_rate( clock_rate_ );
+ bass_freq( bass_freq_ );
+
+ clear();
+
+ return blargg_ok;
+}
+
+blip_resampled_time_t Blip_Buffer::clock_rate_factor( int rate ) const
+{
+ double ratio = (double) sample_rate_ / rate;
+ int factor = (int) floor( ratio * (1 << 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 && sample_rate_ )
+ {
+ shift = 13;
+ int f = (freq << 16) / sample_rate_;
+ while ( (f >>= 1) != 0 && --shift ) { }
+ }
+ bass_shift_ = shift;
+}
+
+void Blip_Buffer::end_frame( blip_time_t t )
+{
+ offset_ += t * factor_;
+ assert( samples_avail() <= (int) buffer_size_ ); // fails if time is past end of buffer
+}
+
+int Blip_Buffer::count_samples( blip_time_t t ) const
+{
+ blip_resampled_time_t last_sample = resampled_time( t ) >> BLIP_BUFFER_ACCURACY;
+ blip_resampled_time_t first_sample = offset_ >> BLIP_BUFFER_ACCURACY;
+ return (int) (last_sample - first_sample);
+}
+
+blip_time_t Blip_Buffer::count_clocks( int count ) const
+{
+ 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( int count )
+{
+ if ( count )
+ {
+ remove_silence( count );
+
+ // copy remaining samples to beginning and clear old samples
+ int remain = samples_avail() + blip_buffer_extra_;
+ memmove( buffer_, buffer_ + count, remain * sizeof *buffer_ );
+ memset( buffer_ + remain, 0, count * sizeof *buffer_ );
+ }
+}
+
+int Blip_Buffer::read_samples( blip_sample_t out_ [], int max_samples, bool stereo )
+{
+ int count = samples_avail();
+ if ( count > max_samples )
+ count = max_samples;
+
+ if ( count )
+ {
+ int const bass = highpass_shift();
+ delta_t const* reader = read_pos() + count;
+ int reader_sum = integrator();
+
+ blip_sample_t* BLARGG_RESTRICT out = out_ + count;
+ if ( stereo )
+ out += count;
+ int offset = -count;
+
+ if ( !stereo )
+ {
+ do
+ {
+ int s = reader_sum >> delta_bits;
+
+ reader_sum -= reader_sum >> bass;
+ reader_sum += reader [offset];
+
+ BLIP_CLAMP( s, s );
+ out [offset] = (blip_sample_t) s;
+ }
+ while ( ++offset );
+ }
+ else
+ {
+ do
+ {
+ int s = reader_sum >> delta_bits;
+
+ reader_sum -= reader_sum >> bass;
+ reader_sum += reader [offset];
+
+ BLIP_CLAMP( s, s );
+ out [offset * 2] = (blip_sample_t) s;
+ }
+ while ( ++offset );
+ }
+
+ set_integrator( reader_sum );
+
+ remove_samples( count );
+ }
+ return count;
+}
+
+void Blip_Buffer::mix_samples( blip_sample_t const in [], int count )
+{
+ delta_t* out = buffer_center_ + (offset_ >> BLIP_BUFFER_ACCURACY);
+
+ int const sample_shift = blip_sample_bits - 16;
+ int prev = 0;
+ while ( --count >= 0 )
+ {
+ int s = *in++ << sample_shift;
+ *out += s - prev;
+ prev = s;
+ ++out;
+ }
+ *out -= prev;
+}
+
+void Blip_Buffer::save_state( blip_buffer_state_t* out )
+{
+ assert( samples_avail() == 0 );
+ out->offset_ = offset_;
+ out->reader_accum_ = reader_accum_;
+ memcpy( out->buf, &buffer_ [offset_ >> BLIP_BUFFER_ACCURACY], sizeof out->buf );
+}
+
+void Blip_Buffer::load_state( blip_buffer_state_t const& in )
+{
+ clear();
+
+ offset_ = in.offset_;
+ reader_accum_ = in.reader_accum_;
+ memcpy( buffer_, in.buf, sizeof in.buf );
+}
+
+
+//// Blip_Synth_
+
+Blip_Synth_Fast_::Blip_Synth_Fast_()
+{
+ buf = NULL;
+ last_amp = 0;
+ delta_factor = 0;
+}
+
+void Blip_Synth_Fast_::volume_unit( double new_unit )
+{
+ delta_factor = int (new_unit * (1 << blip_sample_bits) + 0.5);
+}
+
+#if BLIP_BUFFER_FAST
+
+void blip_eq_t::generate( float* out, int count ) const { }
+
+#else
+
+Blip_Synth_::Blip_Synth_( short p [], int w ) :
+ phases( p ),
+ width( w )
+{
+ volume_unit_ = 0.0;
+ kernel_unit = 0;
+ buf = NULL;
+ last_amp = 0;
+ delta_factor = 0;
+}
+
+#undef PI
+#define PI 3.1415926535897932384626433832795029
+
+// Generates right half of sinc kernel (including center point) with cutoff at
+// sample rate / 2 / oversample. Frequency response at cutoff frequency is
+// treble dB (-6=0.5,-12=0.25). Mid controls frequency that rolloff begins at,
+// cut * sample rate / 2.
+static void gen_sinc( float out [], int out_size, double oversample,
+ double treble, double mid )
+{
+ if ( mid > 0.9999 ) mid = 0.9999;
+ if ( treble < -300.0 ) treble = -300.0;
+ if ( treble > 5.0 ) treble = 5.0;
+
+ double const maxh = 4096.0;
+ double rolloff = pow( 10.0, 1.0 / (maxh * 20.0) * treble / (1.0 - mid) );
+ double const pow_a_n = pow( rolloff, maxh - maxh * mid );
+ double const to_angle = PI / maxh / oversample;
+ for ( int i = 1; i < out_size; i++ )
+ {
+ double angle = i * to_angle;
+ double c = rolloff * cos( angle * maxh - angle ) -
+ cos( angle * maxh );
+ double cos_nc_angle = cos( angle * maxh * mid );
+ double cos_nc1_angle = cos( angle * maxh * mid - angle );
+ double cos_angle = cos( angle );
+
+ c = c * pow_a_n - rolloff * cos_nc1_angle + cos_nc_angle;
+ double d = 1.0 + rolloff * (rolloff - cos_angle - cos_angle);
+ double b = 2.0 - cos_angle - cos_angle;
+ double a = 1.0 - cos_angle - cos_nc_angle + cos_nc1_angle;
+
+ out [i] = (float) ((a * d + c * b) / (b * d)); // a / b + c / d
+ }
+
+ // Approximate center by looking at two points to right. Much simpler
+ // and more reliable than trying to calculate it properly.
+ out [0] = out [1] + 0.5 * (out [1] - out [2]);
+}
+
+// Gain is 1-2800 for beta of 0-10, instead of 1.0 as it should be, but
+// this is corrected by normalization in treble_eq().
+static void kaiser_window( float io [], int count, float beta )
+{
+ int const accuracy = 10;
+
+ float const beta2 = beta * beta;
+ float const step = (float) 0.5 / count;
+ float pos = (float) 0.5;
+ for ( float* const end = io + count; io < end; ++io )
+ {
+ float x = (pos - pos*pos) * beta2;
+ float u = x;
+ float k = 1;
+ float n = 2;
+
+ // Keep refining until adjustment becomes small
+ do
+ {
+ u *= x / (n * n);
+ n += 1;
+ k += u;
+ }
+ while ( k <= u * (1 << accuracy) );
+
+ pos += step;
+ *io *= k;
+ }
+}
+
+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 cutoff_adj = blip_res * 2.25 / count + 0.85;
+ if ( cutoff_adj < 1.02 )
+ cutoff_adj = 1.02;
+ double half_rate = sample_rate * 0.5;
+ if ( cutoff_freq )
+ cutoff_adj = half_rate / cutoff_freq;
+ double cutoff = rolloff_freq * cutoff_adj / half_rate;
+
+ gen_sinc( out, count, oversample * cutoff_adj, treble, cutoff );
+
+ kaiser_window( out, count, kaiser );
+}
+
+void Blip_Synth_::treble_eq( blip_eq_t const& eq )
+{
+ // Generate right half of kernel
+ int const half_size = blip_eq_t::calc_count( width );
+ float fimpulse [blip_res / 2 * (BLIP_MAX_QUALITY - 1) + 1];
+ eq.generate( fimpulse, half_size );
+
+ int i;
+
+ // Find rescale factor. Summing from small to large (right to left)
+ // reduces error.
+ double total = 0.0;
+ for ( i = half_size; --i > 0; )
+ total += fimpulse [i];
+ total = total * 2.0 + fimpulse [0];
+
+ //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 / total;
+ kernel_unit = (int) base_unit;
+
+ // Integrate, first difference, rescale, convert to int
+ double sum = 0;
+ double next = 0;
+ int const size = impulses_size();
+ for ( i = 0; i < size; i++ )
+ {
+ int j = (half_size - 1) - i;
+
+ if ( i >= blip_res )
+ sum += fimpulse [j + blip_res];
+
+ // goes slightly past center, so it needs a little mirroring
+ next += fimpulse [j < 0 ? -j : j];
+
+ // calculate unintereleved index
+ int x = (~i & (blip_res - 1)) * (width >> 1) + (i >> BLIP_PHASE_BITS);
+ assert( (unsigned) x < (unsigned) size );
+
+ // flooring separately virtually eliminates error
+ phases [x] = (short) (int)
+ (floor( sum * rescale + 0.5 ) - floor( next * rescale + 0.5 ));
+ //phases [x] = (short) (int)
+ // floor( sum * rescale - next * rescale + 0.5 );
+ }
+
+ adjust_impulse();
+
+ // volume might require rescaling
+ double vol = volume_unit_;
+ if ( vol )
+ {
+ volume_unit_ = 0.0;
+ volume_unit( vol );
+ }
+}
+
+void Blip_Synth_::adjust_impulse()
+{
+ int const size = impulses_size();
+ int const half_width = width / 2;
+
+ // Sum each phase as would be done when synthesizing, and correct
+ // any that don't add up to exactly kernel_half.
+ for ( int phase = blip_res / 2; --phase >= 0; )
+ {
+ int const fwd = phase * half_width;
+ int const rev = size - half_width - fwd;
+
+ int error = kernel_unit;
+ for ( int i = half_width; --i >= 0; )
+ {
+ error += phases [fwd + i];
+ error += phases [rev + i];
+ }
+ phases [fwd + half_width - 1] -= (short) error;
+
+ // Error shouldn't occur now with improved calculation
+ //if ( error ) printf( "error: %ld\n", error );
+ }
+
+ #if 0
+ for ( int i = 0; i < blip_res; i++, printf( "\n" ) )
+ for ( int j = 0; j < width / 2; j++ )
+ printf( "%5d,", (int) -phases [j + width/2 * i] );
+ #endif
+}
+
+void Blip_Synth_::rescale_kernel( int shift )
+{
+ // Keep values positive to avoid round-towards-zero of sign-preserving
+ // right shift for negative values.
+ int const keep_positive = 0x8000 + (1 << (shift - 1));
+
+ int const half_width = width / 2;
+ for ( int phase = blip_res; --phase >= 0; )
+ {
+ int const fwd = phase * half_width;
+
+ // Integrate, rescale, then differentiate again.
+ // If differences are rescaled directly, more error results.
+ int sum = keep_positive;
+ for ( int i = 0; i < half_width; i++ )
+ {
+ int prev = sum;
+ sum += phases [fwd + i];
+ phases [fwd + i] = (sum >> shift) - (prev >> shift);
+ }
+ }
+
+ adjust_impulse();
+}
+
+void Blip_Synth_::volume_unit( double new_unit )
+{
+ if ( volume_unit_ != new_unit )
+ {
+ // use default eq if it hasn't been set yet
+ if ( !kernel_unit )
+ treble_eq( -8.0 );
+
+ // Factor that kernel must be multiplied by
+ volume_unit_ = new_unit;
+ double factor = new_unit * (1 << blip_sample_bits) / kernel_unit;
+
+ if ( factor > 0.0 )
+ {
+ // If factor is low, reduce amplitude of kernel itself
+ int shift = 0;
+ while ( factor < 2.0 )
+ {
+ shift++;
+ factor *= 2.0;
+ }
+
+ if ( shift )
+ {
+ kernel_unit >>= shift;
+ assert( kernel_unit > 0 ); // fails if volume unit is too low
+
+ rescale_kernel( shift );
+ }
+ }
+
+ delta_factor = -(int) floor( factor + 0.5 );
+ //printf( "delta_factor: %d, kernel_unit: %d\n", delta_factor, kernel_unit );
+ }
+}
+#endif
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