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comparison src/apu/Blip_Buffer.h @ 1:f9f4f1b99eed

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importing src directory
author Robert McIntyre <rlm@mit.edu>
date Sat, 03 Mar 2012 10:31:27 -0600
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0:8ced16adf2e1 1:f9f4f1b99eed
1 // Band-limited sound synthesis buffer
2
3 // Blip_Buffer 0.4.1
4 #ifndef BLIP_BUFFER_H
5 #define BLIP_BUFFER_H
6
7 // internal
8 #include <limits.h>
9 #if INT_MAX < 0x7FFFFFFF || LONG_MAX == 0x7FFFFFFF
10 typedef long blip_long;
11 typedef unsigned long blip_ulong;
12 #else
13 typedef int blip_long;
14 typedef unsigned blip_ulong;
15 #endif
16
17 // Time unit at source clock rate
18 typedef blip_long blip_time_t;
19
20 // Output samples are 16-bit signed, with a range of -32768 to 32767
21 typedef short blip_sample_t;
22 enum { blip_sample_max = 32767 };
23
24 struct blip_buffer_state_t;
25
26 class Blip_Buffer {
27 public:
28 typedef const char* blargg_err_t;
29
30 // Sets output sample rate and buffer length in milliseconds (1/1000 sec, defaults
31 // to 1/4 second) and clears buffer. If there isn't enough memory, leaves buffer
32 // untouched and returns "Out of memory", otherwise returns NULL.
33 blargg_err_t set_sample_rate( long samples_per_sec, int msec_length = 1000 / 4 );
34
35 // Sets number of source time units per second
36 void clock_rate( long clocks_per_sec );
37
38 // Ends current time frame of specified duration and makes its samples available
39 // (along with any still-unread samples) for reading with read_samples(). Begins
40 // a new time frame at the end of the current frame.
41 void end_frame( blip_time_t time );
42
43 // Reads at most 'max_samples' out of buffer into 'dest', removing them from from
44 // the buffer. Returns number of samples actually read and removed. If stereo is
45 // true, increments 'dest' one extra time after writing each sample, to allow
46 // easy interleving of two channels into a stereo output buffer.
47 long read_samples( blip_sample_t* dest, long max_samples, int stereo = 0 );
48
49 // Additional features
50
51 // Removes all available samples and clear buffer to silence. If 'entire_buffer' is
52 // false, just clears out any samples waiting rather than the entire buffer.
53 void clear( int entire_buffer = 1 );
54
55 // Number of samples available for reading with read_samples()
56 long samples_avail() const;
57
58 // Removes 'count' samples from those waiting to be read
59 void remove_samples( long count );
60
61 // Sets frequency high-pass filter frequency, where higher values reduce bass more
62 void bass_freq( int frequency );
63
64 // Current output sample rate
65 long sample_rate() const;
66
67 // Length of buffer in milliseconds
68 int length() const;
69
70 // Number of source time units per second
71 long clock_rate() const;
72
73 // Experimental features
74
75 // Saves state, including high-pass filter and tails of last deltas.
76 // All samples must have been read from buffer before calling this.
77 void save_state( blip_buffer_state_t* out );
78
79 // Loads state. State must have been saved from Blip_Buffer with same
80 // settings during same run of program. States can NOT be stored on disk.
81 // Clears buffer before loading state.
82 void load_state( blip_buffer_state_t const& in );
83
84 // Number of samples delay from synthesis to samples read out
85 int output_latency() const;
86
87 // Counts number of clocks needed until 'count' samples will be available.
88 // If buffer can't even hold 'count' samples, returns number of clocks until
89 // buffer becomes full.
90 blip_time_t count_clocks( long count ) const;
91
92 // Number of raw samples that can be mixed within frame of specified duration.
93 long count_samples( blip_time_t duration ) const;
94
95 // Mixes in 'count' samples from 'buf_in'
96 void mix_samples( blip_sample_t const* buf_in, long count );
97
98
99 // Signals that sound has been added to buffer. Could be done automatically in
100 // Blip_Synth, but that would affect performance more, as you can arrange that
101 // this is called only once per time frame rather than for every delta.
102 void set_modified() { modified_ = this; }
103
104 // not documented yet
105 blip_ulong unsettled() const;
106 Blip_Buffer* clear_modified() { Blip_Buffer* b = modified_; modified_ = 0; return b; }
107 void remove_silence( long count );
108 typedef blip_ulong blip_resampled_time_t;
109 blip_resampled_time_t resampled_duration( int t ) const { return t * factor_; }
110 blip_resampled_time_t resampled_time( blip_time_t t ) const { return t * factor_ + offset_; }
111 blip_resampled_time_t clock_rate_factor( long clock_rate ) const;
112 public:
113 Blip_Buffer();
114 ~Blip_Buffer();
115
116 // Deprecated
117 typedef blip_resampled_time_t resampled_time_t;
118 blargg_err_t sample_rate( long r ) { return set_sample_rate( r ); }
119 blargg_err_t sample_rate( long r, int msec ) { return set_sample_rate( r, msec ); }
120 private:
121 // noncopyable
122 Blip_Buffer( const Blip_Buffer& );
123 Blip_Buffer& operator = ( const Blip_Buffer& );
124 public:
125 typedef blip_long buf_t_;
126 blip_ulong factor_;
127 blip_resampled_time_t offset_;
128 buf_t_* buffer_;
129 blip_long buffer_size_;
130 blip_long reader_accum_;
131 int bass_shift_;
132 private:
133 long sample_rate_;
134 long clock_rate_;
135 int bass_freq_;
136 int length_;
137 Blip_Buffer* modified_; // non-zero = true (more optimal than using bool, heh)
138 friend class Blip_Reader;
139 };
140
141 #ifdef HAVE_CONFIG_H
142 #include "config.h"
143 #endif
144
145 // Number of bits in resample ratio fraction. Higher values give a more accurate ratio
146 // but reduce maximum buffer size.
147 #ifndef BLIP_BUFFER_ACCURACY
148 #define BLIP_BUFFER_ACCURACY 16
149 #endif
150
151 // Number bits in phase offset. Fewer than 6 bits (64 phase offsets) results in
152 // noticeable broadband noise when synthesizing high frequency square waves.
153 // Affects size of Blip_Synth objects since they store the waveform directly.
154 #ifndef BLIP_PHASE_BITS
155 #if BLIP_BUFFER_FAST
156 #define BLIP_PHASE_BITS 8
157 #else
158 #define BLIP_PHASE_BITS 6
159 #endif
160 #endif
161
162 // Internal
163 typedef blip_ulong blip_resampled_time_t;
164 int const blip_widest_impulse_ = 16;
165 int const blip_buffer_extra_ = blip_widest_impulse_ + 2;
166 int const blip_res = 1 << BLIP_PHASE_BITS;
167 class blip_eq_t;
168
169 class Blip_Synth_Fast_ {
170 public:
171 Blip_Buffer* buf;
172 int last_amp;
173 int delta_factor;
174
175 void volume_unit( double );
176 Blip_Synth_Fast_();
177 void treble_eq( blip_eq_t const& ) { }
178 };
179
180 class Blip_Synth_ {
181 public:
182 Blip_Buffer* buf;
183 int last_amp;
184 int delta_factor;
185
186 void volume_unit( double );
187 Blip_Synth_( short* impulses, int width );
188 void treble_eq( blip_eq_t const& );
189 private:
190 double volume_unit_;
191 short* const impulses;
192 int const width;
193 blip_long kernel_unit;
194 int impulses_size() const { return blip_res / 2 * width + 1; }
195 void adjust_impulse();
196 };
197
198 // Quality level, better = slower. In general, use blip_good_quality.
199 const int blip_med_quality = 8;
200 const int blip_good_quality = 12;
201 const int blip_high_quality = 16;
202
203 // Range specifies the greatest expected change in amplitude. Calculate it
204 // by finding the difference between the maximum and minimum expected
205 // amplitudes (max - min).
206 template<int quality,int range>
207 class Blip_Synth {
208 public:
209 // Sets overall volume of waveform
210 void volume( double v ) { impl.volume_unit( v * (1.0 / (range < 0 ? -range : range)) ); }
211
212 // Configures low-pass filter (see blip_buffer.txt)
213 void treble_eq( blip_eq_t const& eq ) { impl.treble_eq( eq ); }
214
215 // Gets/sets Blip_Buffer used for output
216 Blip_Buffer* output() const { return impl.buf; }
217 void output( Blip_Buffer* b ) { impl.buf = b; impl.last_amp = 0; }
218
219 // Updates amplitude of waveform at given time. Using this requires a separate
220 // Blip_Synth for each waveform.
221 void update( blip_time_t time, int amplitude );
222
223 // Low-level interface
224
225 // Adds an amplitude transition of specified delta, optionally into specified buffer
226 // rather than the one set with output(). Delta can be positive or negative.
227 // The actual change in amplitude is delta * (volume / range)
228 void offset( blip_time_t, int delta, Blip_Buffer* ) const;
229 void offset( blip_time_t t, int delta ) const { offset( t, delta, impl.buf ); }
230
231 // Works directly in terms of fractional output samples. Contact author for more info.
232 void offset_resampled( blip_resampled_time_t, int delta, Blip_Buffer* ) const;
233
234 // Same as offset(), except code is inlined for higher performance
235 void offset_inline( blip_time_t t, int delta, Blip_Buffer* buf ) const {
236 offset_resampled( t * buf->factor_ + buf->offset_, delta, buf );
237 }
238 void offset_inline( blip_time_t t, int delta ) const {
239 offset_resampled( t * impl.buf->factor_ + impl.buf->offset_, delta, impl.buf );
240 }
241
242 private:
243 #if BLIP_BUFFER_FAST
244 Blip_Synth_Fast_ impl;
245 #else
246 Blip_Synth_ impl;
247 typedef short imp_t;
248 imp_t impulses [blip_res * (quality / 2) + 1];
249 public:
250 Blip_Synth() : impl( impulses, quality ) { }
251 #endif
252 };
253
254 // Low-pass equalization parameters
255 class blip_eq_t {
256 public:
257 // Logarithmic rolloff to treble dB at half sampling rate. Negative values reduce
258 // treble, small positive values (0 to 5.0) increase treble.
259 blip_eq_t( double treble_db = 0 );
260
261 // See blip_buffer.txt
262 blip_eq_t( double treble, long rolloff_freq, long sample_rate, long cutoff_freq = 0 );
263
264 private:
265 double treble;
266 long rolloff_freq;
267 long sample_rate;
268 long cutoff_freq;
269 void generate( float* out, int count ) const;
270 friend class Blip_Synth_;
271 };
272
273 int const blip_sample_bits = 30;
274
275 // Dummy Blip_Buffer to direct sound output to, for easy muting without
276 // having to stop sound code.
277 class Silent_Blip_Buffer : public Blip_Buffer {
278 buf_t_ buf [blip_buffer_extra_ + 1];
279 public:
280 // The following cannot be used (an assertion will fail if attempted):
281 blargg_err_t set_sample_rate( long samples_per_sec, int msec_length );
282 blip_time_t count_clocks( long count ) const;
283 void mix_samples( blip_sample_t const* buf, long count );
284
285 Silent_Blip_Buffer();
286 };
287
288 #if __GNUC__ >= 3 || _MSC_VER >= 1400
289 #define BLIP_RESTRICT __restrict
290 #else
291 #define BLIP_RESTRICT
292 #endif
293
294 // Optimized reading from Blip_Buffer, for use in custom sample output
295
296 // Begins reading from buffer. Name should be unique to the current block.
297 #define BLIP_READER_BEGIN( name, blip_buffer ) \
298 const Blip_Buffer::buf_t_* BLIP_RESTRICT name##_reader_buf = (blip_buffer).buffer_;\
299 blip_long name##_reader_accum = (blip_buffer).reader_accum_
300
301 // Gets value to pass to BLIP_READER_NEXT()
302 #define BLIP_READER_BASS( blip_buffer ) ((blip_buffer).bass_shift_)
303
304 // Constant value to use instead of BLIP_READER_BASS(), for slightly more optimal
305 // code at the cost of having no bass control
306 int const blip_reader_default_bass = 9;
307
308 // Current sample
309 #define BLIP_READER_READ( name ) (name##_reader_accum >> (blip_sample_bits - 16))
310
311 // Current raw sample in full internal resolution
312 #define BLIP_READER_READ_RAW( name ) (name##_reader_accum)
313
314 // Advances to next sample
315 #define BLIP_READER_NEXT( name, bass ) \
316 (void) (name##_reader_accum += *name##_reader_buf++ - (name##_reader_accum >> (bass)))
317
318 // Ends reading samples from buffer. The number of samples read must now be removed
319 // using Blip_Buffer::remove_samples().
320 #define BLIP_READER_END( name, blip_buffer ) \
321 (void) ((blip_buffer).reader_accum_ = name##_reader_accum)
322
323
324 // experimental
325 #define BLIP_READER_ADJ_( name, offset ) (name##_reader_buf += offset)
326
327 blip_long const blip_reader_idx_factor = sizeof (Blip_Buffer::buf_t_);
328
329 #define BLIP_READER_NEXT_IDX_( name, bass, idx ) {\
330 name##_reader_accum -= name##_reader_accum >> (bass);\
331 name##_reader_accum += name##_reader_buf [(idx)];\
332 }
333
334 #define BLIP_READER_NEXT_RAW_IDX_( name, bass, idx ) {\
335 name##_reader_accum -= name##_reader_accum >> (bass);\
336 name##_reader_accum +=\
337 *(Blip_Buffer::buf_t_ const*) ((char const*) name##_reader_buf + (idx));\
338 }
339
340 // Compatibility with older version
341 const long blip_unscaled = 65535;
342 const int blip_low_quality = blip_med_quality;
343 const int blip_best_quality = blip_high_quality;
344
345 // Deprecated; use BLIP_READER macros as follows:
346 // Blip_Reader r; r.begin( buf ); -> BLIP_READER_BEGIN( r, buf );
347 // int bass = r.begin( buf ) -> BLIP_READER_BEGIN( r, buf ); int bass = BLIP_READER_BASS( buf );
348 // r.read() -> BLIP_READER_READ( r )
349 // r.read_raw() -> BLIP_READER_READ_RAW( r )
350 // r.next( bass ) -> BLIP_READER_NEXT( r, bass )
351 // r.next() -> BLIP_READER_NEXT( r, blip_reader_default_bass )
352 // r.end( buf ) -> BLIP_READER_END( r, buf )
353 class Blip_Reader {
354 public:
355 int begin( Blip_Buffer& );
356 blip_long read() const { return accum >> (blip_sample_bits - 16); }
357 blip_long read_raw() const { return accum; }
358 void next( int bass_shift = 9 ) { accum += *buf++ - (accum >> bass_shift); }
359 void end( Blip_Buffer& b ) { b.reader_accum_ = accum; }
360 private:
361 const Blip_Buffer::buf_t_* buf;
362 blip_long accum;
363 };
364
365 #if defined (_M_IX86) || defined (_M_IA64) || defined (__i486__) || \
366 defined (__x86_64__) || defined (__ia64__) || defined (__i386__)
367 #define BLIP_CLAMP_( in ) in < -0x8000 || 0x7FFF < in
368 #else
369 #define BLIP_CLAMP_( in ) (blip_sample_t) in != in
370 #endif
371
372 // Clamp sample to blip_sample_t range
373 #define BLIP_CLAMP( sample, out )\
374 { if ( BLIP_CLAMP_( (sample) ) ) (out) = ((sample) >> 24) ^ 0x7FFF; }
375
376 struct blip_buffer_state_t
377 {
378 blip_resampled_time_t offset_;
379 blip_long reader_accum_;
380 blip_long buf [blip_buffer_extra_];
381 };
382
383 // End of public interface
384
385 #ifndef assert
386 #include <assert.h>
387 #endif
388
389 template<int quality,int range>
390 inline void Blip_Synth<quality,range>::offset_resampled( blip_resampled_time_t time,
391 int delta, Blip_Buffer* blip_buf ) const
392 {
393 // If this assertion fails, it means that an attempt was made to add a delta
394 // at a negative time or past the end of the buffer.
395 assert( (blip_long) (time >> BLIP_BUFFER_ACCURACY) < blip_buf->buffer_size_ );
396
397 delta *= impl.delta_factor;
398 blip_long* BLIP_RESTRICT buf = blip_buf->buffer_ + (time >> BLIP_BUFFER_ACCURACY);
399 int phase = (int) (time >> (BLIP_BUFFER_ACCURACY - BLIP_PHASE_BITS) & (blip_res - 1));
400
401 #if BLIP_BUFFER_FAST
402 blip_long left = buf [0] + delta;
403
404 // Kind of crappy, but doing shift after multiply results in overflow.
405 // Alternate way of delaying multiply by delta_factor results in worse
406 // sub-sample resolution.
407 blip_long right = (delta >> BLIP_PHASE_BITS) * phase;
408 left -= right;
409 right += buf [1];
410
411 buf [0] = left;
412 buf [1] = right;
413 #else
414
415 int const fwd = (blip_widest_impulse_ - quality) / 2;
416 int const rev = fwd + quality - 2;
417 int const mid = quality / 2 - 1;
418
419 imp_t const* BLIP_RESTRICT imp = impulses + blip_res - phase;
420
421 #if defined (_M_IX86) || defined (_M_IA64) || defined (__i486__) || \
422 defined (__x86_64__) || defined (__ia64__) || defined (__i386__)
423
424 // this straight forward version gave in better code on GCC for x86
425
426 #define ADD_IMP( out, in ) \
427 buf [out] += (blip_long) imp [blip_res * (in)] * delta
428
429 #define BLIP_FWD( i ) {\
430 ADD_IMP( fwd + i, i );\
431 ADD_IMP( fwd + 1 + i, i + 1 );\
432 }
433 #define BLIP_REV( r ) {\
434 ADD_IMP( rev - r, r + 1 );\
435 ADD_IMP( rev + 1 - r, r );\
436 }
437
438 BLIP_FWD( 0 )
439 if ( quality > 8 ) BLIP_FWD( 2 )
440 if ( quality > 12 ) BLIP_FWD( 4 )
441 {
442 ADD_IMP( fwd + mid - 1, mid - 1 );
443 ADD_IMP( fwd + mid , mid );
444 imp = impulses + phase;
445 }
446 if ( quality > 12 ) BLIP_REV( 6 )
447 if ( quality > 8 ) BLIP_REV( 4 )
448 BLIP_REV( 2 )
449
450 ADD_IMP( rev , 1 );
451 ADD_IMP( rev + 1, 0 );
452
453 #undef ADD_IMP
454
455 #else
456
457 // for RISC processors, help compiler by reading ahead of writes
458
459 #define BLIP_FWD( i ) {\
460 blip_long t0 = i0 * delta + buf [fwd + i];\
461 blip_long t1 = imp [blip_res * (i + 1)] * delta + buf [fwd + 1 + i];\
462 i0 = imp [blip_res * (i + 2)];\
463 buf [fwd + i] = t0;\
464 buf [fwd + 1 + i] = t1;\
465 }
466 #define BLIP_REV( r ) {\
467 blip_long t0 = i0 * delta + buf [rev - r];\
468 blip_long t1 = imp [blip_res * r] * delta + buf [rev + 1 - r];\
469 i0 = imp [blip_res * (r - 1)];\
470 buf [rev - r] = t0;\
471 buf [rev + 1 - r] = t1;\
472 }
473
474 blip_long i0 = *imp;
475 BLIP_FWD( 0 )
476 if ( quality > 8 ) BLIP_FWD( 2 )
477 if ( quality > 12 ) BLIP_FWD( 4 )
478 {
479 blip_long t0 = i0 * delta + buf [fwd + mid - 1];
480 blip_long t1 = imp [blip_res * mid] * delta + buf [fwd + mid ];
481 imp = impulses + phase;
482 i0 = imp [blip_res * mid];
483 buf [fwd + mid - 1] = t0;
484 buf [fwd + mid ] = t1;
485 }
486 if ( quality > 12 ) BLIP_REV( 6 )
487 if ( quality > 8 ) BLIP_REV( 4 )
488 BLIP_REV( 2 )
489
490 blip_long t0 = i0 * delta + buf [rev ];
491 blip_long t1 = *imp * delta + buf [rev + 1];
492 buf [rev ] = t0;
493 buf [rev + 1] = t1;
494 #endif
495
496 #endif
497 }
498
499 #undef BLIP_FWD
500 #undef BLIP_REV
501
502 template<int quality,int range>
503 #if BLIP_BUFFER_FAST
504 inline
505 #endif
506 void Blip_Synth<quality,range>::offset( blip_time_t t, int delta, Blip_Buffer* buf ) const
507 {
508 offset_resampled( t * buf->factor_ + buf->offset_, delta, buf );
509 }
510
511 template<int quality,int range>
512 #if BLIP_BUFFER_FAST
513 inline
514 #endif
515 void Blip_Synth<quality,range>::update( blip_time_t t, int amp )
516 {
517 int delta = amp - impl.last_amp;
518 impl.last_amp = amp;
519 offset_resampled( t * impl.buf->factor_ + impl.buf->offset_, delta, impl.buf );
520 }
521
522 inline blip_eq_t::blip_eq_t( double t ) :
523 treble( t ), rolloff_freq( 0 ), sample_rate( 44100 ), cutoff_freq( 0 ) { }
524 inline blip_eq_t::blip_eq_t( double t, long rf, long sr, long cf ) :
525 treble( t ), rolloff_freq( rf ), sample_rate( sr ), cutoff_freq( cf ) { }
526
527 inline int Blip_Buffer::length() const { return length_; }
528 inline long Blip_Buffer::samples_avail() const { return (long) (offset_ >> BLIP_BUFFER_ACCURACY); }
529 inline long Blip_Buffer::sample_rate() const { return sample_rate_; }
530 inline int Blip_Buffer::output_latency() const { return blip_widest_impulse_ / 2; }
531 inline long Blip_Buffer::clock_rate() const { return clock_rate_; }
532 inline void Blip_Buffer::clock_rate( long cps ) { factor_ = clock_rate_factor( clock_rate_ = cps ); }
533
534 inline int Blip_Reader::begin( Blip_Buffer& blip_buf )
535 {
536 buf = blip_buf.buffer_;
537 accum = blip_buf.reader_accum_;
538 return blip_buf.bass_shift_;
539 }
540
541 inline void Blip_Buffer::remove_silence( long count )
542 {
543 // fails if you try to remove more samples than available
544 assert( count <= samples_avail() );
545 offset_ -= (blip_resampled_time_t) count << BLIP_BUFFER_ACCURACY;
546 }
547
548 inline blip_ulong Blip_Buffer::unsettled() const
549 {
550 return reader_accum_ >> (blip_sample_bits - 16);
551 }
552
553 int const blip_max_length = 0;
554 int const blip_default_length = 250; // 1/4 second
555
556 #endif