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Diffstat (limited to 'flow/gsl/gslsignal.c')
| -rw-r--r-- | flow/gsl/gslsignal.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/flow/gsl/gslsignal.c b/flow/gsl/gslsignal.c new file mode 100644 index 0000000..9afc5bb --- /dev/null +++ b/flow/gsl/gslsignal.c @@ -0,0 +1,258 @@ +/* GSL - Generic Sound Layer + * Copyright (C) 2001-2002 Tim Janik and Stefan Westerfeld + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Library General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * + * This library 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 General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place, Suite 330, + * Boston, MA 02111-1307, USA. + */ +#include "gslsignal.h" + +#include "gslcommon.h" + + +/* --- frequency modulation --- */ +void +gsl_frequency_modulator (const GslFrequencyModulator *fm, + guint n_values, + const gfloat *ifreq, + const gfloat *ifmod, + gfloat *fm_buffer) +{ + gfloat *bound, fine_tune, fm_strength; + gboolean with_fine_tune; + + fine_tune = gsl_cent_factor (fm->fine_tune); + with_fine_tune = fm->fine_tune != 0; + fm_strength = fm->fm_strength; + + bound = fm_buffer + n_values; + if (ifreq && ifmod) + { + if (fm->exponential_fm) + { + if (with_fine_tune) + do { + *fm_buffer++ = *ifreq++ * gsl_approx_exp2 (fm_strength * *ifmod++) * fine_tune; + } while (fm_buffer < bound); + else + do { + *fm_buffer++ = *ifreq++ * gsl_approx_exp2 (fm_strength * *ifmod++); + } while (fm_buffer < bound); + } + else + { + if (with_fine_tune) + do { + *fm_buffer++ = *ifreq++ * (1 + fm_strength * *ifmod++) * fine_tune; + } while (fm_buffer < bound); + else + do { + *fm_buffer++ = *ifreq++ * (1 + fm_strength * *ifmod++); + } while (fm_buffer < bound); + } + } + else if (ifmod) + { + gfloat signal_freq = fm->signal_freq * fine_tune; + + if (fm->exponential_fm) + do { + *fm_buffer++ = signal_freq * gsl_approx_exp2 (fm_strength * *ifmod++); + } while (fm_buffer < bound); + else + do { + *fm_buffer++ = signal_freq * (1 + fm_strength * *ifmod++); + } while (fm_buffer < bound); + } + else if (ifreq) + { + if (with_fine_tune) + do { + *fm_buffer++ = *ifreq++ * fine_tune; + } while (fm_buffer < bound); + else + do { + *fm_buffer++ = *ifreq++; + } while (fm_buffer < bound); + } + else + { + gfloat signal_freq = fm->signal_freq * fine_tune; + + do { + *fm_buffer++ = signal_freq; + } while (fm_buffer < bound); + } +} + + +/* --- windows --- */ +double +gsl_window_bartlett (double x) /* triangle */ +{ + if (fabs (x) > 1) + return 0; + + return 1.0 - fabs (x); +} + +double +gsl_window_blackman (double x) +{ + if (fabs (x) > 1) + return 0; + + return 0.42 + 0.5 * cos (GSL_PI * x) + 0.08 * cos (2.0 * GSL_PI * x); +} + +double +gsl_window_cos (double x) /* von Hann window */ +{ + if (fabs (x) > 1) + return 0; + + return 0.5 * cos (x * GSL_PI) + 0.5; +} + +double +gsl_window_hamming (double x) /* sharp (rectangle) cutoffs at boundaries */ +{ + if (fabs (x) > 1) + return 0; + + return 0.54 + 0.46 * cos (GSL_PI * x); +} + +double +gsl_window_sinc (double x) /* noramlied C. Lanczos window */ +{ + if (fabs (x) > 1) + return 0; + x = x * GSL_PI; + if (fabs (x) < 1e-12) + return 1.0; + else + return sin (x) / x; +} + +double +gsl_window_rect (double x) /* a square */ +{ + if (fabs (x) > 1) + return 0; + return 1.0; +} + +/* +cos_roll_off(x)= x>fh?0:x<fl?1:cos(pi/2.*((fl-x)/(fh-fl))) +*/ + + +/* --- cents & init --- */ +const gdouble *gsl_cent_table = NULL; +#define GSL_2_RAISED_TO_1_OVER_1200_d ( /* 2^(1/1200) */ \ + 1.0005777895065548488418016859213821589946746826171875) +void +_gsl_init_signal (void) +{ + static gdouble cent_table_space[201]; + gint i; + + /* cent table initialization, + * allow negative indexing within [-100..+100] + */ + gsl_cent_table = cent_table_space + 100; + for (i = -100; i <= 100; i++) + cent_table_space[100 + i] = pow (GSL_2_RAISED_TO_1_OVER_1200_d, i); +} + + +/* --- gsl_approx_atan1() --- */ +double +gsl_approx_atan1_prescale (double boost_amount) +{ + double max_boost_factor = 100; /* atan1(x*100) gets pretty close to 1 for x=1 */ + double recip_tan_1_div_0_75 = 0.24202942695518667705824990442766; /* 1/tan(1/0.75) */ + double scale; + + g_return_val_if_fail (boost_amount >= 0 && boost_amount <= 1.0, 1.0); + + /* scale boost_amount from [0..1] to -1..1 */ + boost_amount = boost_amount * 2 - 1.0; + + /* prescale factor for atan1(x*prescale), ranges from 1/max_boost_factor..max_boost_factor */ + scale = pow (max_boost_factor, tan (boost_amount / 0.75) * recip_tan_1_div_0_75); + + return scale; +} + + +/* --- exp2f() approximation taylor coefficients finder --- */ +#if 0 +#include <stdio.h> +double +exp2coeff (int n) +{ + double r = 1; + int i; + + for (i = 1; i <= n; i++) + { + r *= GSL_LN2; + r /= i; + } + return r; +} +/* generate taylor coefficients */ +int +main (int argc, + char *argv[]) +{ + int i; + + for (i = 0; i < 20; i++) + printf ("#define EXP2_TAYLOR_COEFF_%u\t(%.40f)\n", i, exp2coeff (i)); + + return 0; +} +/* test/bench program */ +#define _GNU_SOURCE +#include <math.h> +int +main (int argc, + char *argv[]) +{ + double x, dummy = 0, l = 4; + + if (1) /* print errors */ + for (x = -3; x < 3.01; x += 0.1) + { + g_print ("%+f %+1.20f \t (%.20f - %.20f)\n", + x, exp (x * GSL_LN2) - gsl_signal_exp2 (x), + exp (x * GSL_LN2), gsl_signal_exp2 (x)); + } + + if (0) /* bench test */ + for (x = -l; x < l; x += 0.000001) + { + dummy += gsl_signal_exp2 (x); + // dummy += exp2f (x); + } + + g_print ("%f\r \n", dummy); + + return 0; +} +#endif /* coeff generation */ + |