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Diffstat (limited to 'libs/fluidsynth/src/fluid_conv.c')
| -rw-r--r-- | libs/fluidsynth/src/fluid_conv.c | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/libs/fluidsynth/src/fluid_conv.c b/libs/fluidsynth/src/fluid_conv.c new file mode 100644 index 0000000000..1a790cfbfb --- /dev/null +++ b/libs/fluidsynth/src/fluid_conv.c @@ -0,0 +1,320 @@ +/* FluidSynth - A Software Synthesizer + * + * Copyright (C) 2003 Peter Hanappe and others. + * + * 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 + * Library 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., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA + */ + +#include "fluid_conv.h" + + +/* conversion tables */ +fluid_real_t fluid_ct2hz_tab[FLUID_CENTS_HZ_SIZE]; +fluid_real_t fluid_cb2amp_tab[FLUID_CB_AMP_SIZE]; +fluid_real_t fluid_atten2amp_tab[FLUID_ATTEN_AMP_SIZE]; +fluid_real_t fluid_posbp_tab[128]; +fluid_real_t fluid_concave_tab[128]; +fluid_real_t fluid_convex_tab[128]; +fluid_real_t fluid_pan_tab[FLUID_PAN_SIZE]; + +/* + * void fluid_synth_init + * + * Does all the initialization for this module. + */ +void +fluid_conversion_config(void) +{ + int i; + double x; + + for (i = 0; i < FLUID_CENTS_HZ_SIZE; i++) { + fluid_ct2hz_tab[i] = (fluid_real_t) pow(2.0, (double) i / 1200.0); + } + + /* centibels to amplitude conversion + * Note: SF2.01 section 8.1.3: Initial attenuation range is + * between 0 and 144 dB. Therefore a negative attenuation is + * not allowed. + */ + for (i = 0; i < FLUID_CB_AMP_SIZE; i++) { + fluid_cb2amp_tab[i] = (fluid_real_t) pow(10.0, (double) i / -200.0); + } + + /* NOTE: EMU8k and EMU10k devices don't conform to the SoundFont + * specification in regards to volume attenuation. The below calculation + * is an approx. equation for generating a table equivelant to the + * cb_to_amp_table[] in tables.c of the TiMidity++ source, which I'm told + * was generated from device testing. By the spec this should be centibels. + */ + for (i = 0; i < FLUID_ATTEN_AMP_SIZE; i++) { + fluid_atten2amp_tab[i] = (fluid_real_t) pow(10.0, (double) i / FLUID_ATTEN_POWER_FACTOR); + } + + /* initialize the conversion tables (see fluid_mod.c + fluid_mod_get_value cases 4 and 8) */ + + /* concave unipolar positive transform curve */ + fluid_concave_tab[0] = 0.0; + fluid_concave_tab[127] = 1.0; + + /* convex unipolar positive transform curve */ + fluid_convex_tab[0] = 0; + fluid_convex_tab[127] = 1.0; + x = log10(128.0 / 127.0); + + /* There seems to be an error in the specs. The equations are + implemented according to the pictures on SF2.01 page 73. */ + + for (i = 1; i < 127; i++) { + x = -20.0 / 96.0 * log((i * i) / (127.0 * 127.0)) / log(10.0); + fluid_convex_tab[i] = (fluid_real_t) (1.0 - x); + fluid_concave_tab[127 - i] = (fluid_real_t) x; + } + + /* initialize the pan conversion table */ + x = PI / 2.0 / (FLUID_PAN_SIZE - 1.0); + for (i = 0; i < FLUID_PAN_SIZE; i++) { + fluid_pan_tab[i] = (fluid_real_t) sin(i * x); + } +} + +/* + * fluid_ct2hz + */ +fluid_real_t +fluid_ct2hz_real(fluid_real_t cents) +{ + if (cents < 0) + return (fluid_real_t) 1.0; + else if (cents < 900) { + return (fluid_real_t) 6.875 * fluid_ct2hz_tab[(int) (cents + 300)]; + } else if (cents < 2100) { + return (fluid_real_t) 13.75 * fluid_ct2hz_tab[(int) (cents - 900)]; + } else if (cents < 3300) { + return (fluid_real_t) 27.5 * fluid_ct2hz_tab[(int) (cents - 2100)]; + } else if (cents < 4500) { + return (fluid_real_t) 55.0 * fluid_ct2hz_tab[(int) (cents - 3300)]; + } else if (cents < 5700) { + return (fluid_real_t) 110.0 * fluid_ct2hz_tab[(int) (cents - 4500)]; + } else if (cents < 6900) { + return (fluid_real_t) 220.0 * fluid_ct2hz_tab[(int) (cents - 5700)]; + } else if (cents < 8100) { + return (fluid_real_t) 440.0 * fluid_ct2hz_tab[(int) (cents - 6900)]; + } else if (cents < 9300) { + return (fluid_real_t) 880.0 * fluid_ct2hz_tab[(int) (cents - 8100)]; + } else if (cents < 10500) { + return (fluid_real_t) 1760.0 * fluid_ct2hz_tab[(int) (cents - 9300)]; + } else if (cents < 11700) { + return (fluid_real_t) 3520.0 * fluid_ct2hz_tab[(int) (cents - 10500)]; + } else if (cents < 12900) { + return (fluid_real_t) 7040.0 * fluid_ct2hz_tab[(int) (cents - 11700)]; + } else if (cents < 14100) { + return (fluid_real_t) 14080.0 * fluid_ct2hz_tab[(int) (cents - 12900)]; + } else { + return (fluid_real_t) 1.0; /* some loony trying to make you deaf */ + } +} + +/* + * fluid_ct2hz + */ +fluid_real_t +fluid_ct2hz(fluid_real_t cents) +{ + /* Filter fc limit: SF2.01 page 48 # 8 */ + if (cents >= 13500){ + cents = 13500; /* 20 kHz */ + } else if (cents < 1500){ + cents = 1500; /* 20 Hz */ + } + return fluid_ct2hz_real(cents); +} + +/* + * fluid_cb2amp + * + * in: a value between 0 and 960, 0 is no attenuation + * out: a value between 1 and 0 + */ +fluid_real_t +fluid_cb2amp(fluid_real_t cb) +{ + /* + * cb: an attenuation in 'centibels' (1/10 dB) + * SF2.01 page 49 # 48 limits it to 144 dB. + * 96 dB is reasonable for 16 bit systems, 144 would make sense for 24 bit. + */ + + /* minimum attenuation: 0 dB */ + if (cb < 0) { + return 1.0; + } + if (cb >= FLUID_CB_AMP_SIZE) { + return 0.0; + } + return fluid_cb2amp_tab[(int) cb]; +} + +/* + * fluid_atten2amp + * + * in: a value between 0 and 1440, 0 is no attenuation + * out: a value between 1 and 0 + * + * Note: Volume attenuation is supposed to be centibels but EMU8k/10k don't + * follow this. Thats the reason for separate fluid_cb2amp and fluid_atten2amp. + */ +fluid_real_t +fluid_atten2amp(fluid_real_t atten) +{ + if (atten < 0) return 1.0; + else if (atten >= FLUID_ATTEN_AMP_SIZE) return 0.0; + else return fluid_atten2amp_tab[(int) atten]; +} + +/* + * fluid_tc2sec_delay + */ +fluid_real_t +fluid_tc2sec_delay(fluid_real_t tc) +{ + /* SF2.01 section 8.1.2 items 21, 23, 25, 33 + * SF2.01 section 8.1.3 items 21, 23, 25, 33 + * + * The most negative number indicates a delay of 0. Range is limited + * from -12000 to 5000 */ + if (tc <= -32768.0f) { + return (fluid_real_t) 0.0f; + }; + if (tc < -12000.) { + tc = (fluid_real_t) -12000.0f; + } + if (tc > 5000.0f) { + tc = (fluid_real_t) 5000.0f; + } + return (fluid_real_t) pow(2.0, (double) tc / 1200.0); +} + +/* + * fluid_tc2sec_attack + */ +fluid_real_t +fluid_tc2sec_attack(fluid_real_t tc) +{ + /* SF2.01 section 8.1.2 items 26, 34 + * SF2.01 section 8.1.3 items 26, 34 + * The most negative number indicates a delay of 0 + * Range is limited from -12000 to 8000 */ + if (tc<=-32768.){return (fluid_real_t) 0.0;}; + if (tc<-12000.){tc=(fluid_real_t) -12000.0;}; + if (tc>8000.){tc=(fluid_real_t) 8000.0;}; + return (fluid_real_t) pow(2.0, (double) tc / 1200.0); +} + +/* + * fluid_tc2sec + */ +fluid_real_t +fluid_tc2sec(fluid_real_t tc) +{ + /* No range checking here! */ + return (fluid_real_t) pow(2.0, (double) tc / 1200.0); +} + +/* + * fluid_tc2sec_release + */ +fluid_real_t +fluid_tc2sec_release(fluid_real_t tc) +{ + /* SF2.01 section 8.1.2 items 30, 38 + * SF2.01 section 8.1.3 items 30, 38 + * No 'most negative number' rule here! + * Range is limited from -12000 to 8000 */ + if (tc<=-32768.){return (fluid_real_t) 0.0;}; + if (tc<-12000.){tc=(fluid_real_t) -12000.0;}; + if (tc>8000.){tc=(fluid_real_t) 8000.0;}; + return (fluid_real_t) pow(2.0, (double) tc / 1200.0); +} + +/* + * fluid_act2hz + * + * Convert from absolute cents to Hertz + */ +fluid_real_t +fluid_act2hz(fluid_real_t c) +{ + return (fluid_real_t) (8.176 * pow(2.0, (double) c / 1200.0)); +} + +/* + * fluid_hz2ct + * + * Convert from Hertz to cents + */ +fluid_real_t +fluid_hz2ct(fluid_real_t f) +{ + return (fluid_real_t) (6900 + 1200 * log(f / 440.0) / log(2.0)); +} + +/* + * fluid_pan + */ +fluid_real_t +fluid_pan(fluid_real_t c, int left) +{ + if (left) { + c = -c; + } + if (c < -500) { + return (fluid_real_t) 0.0; + } else if (c > 500) { + return (fluid_real_t) 1.0; + } else { + return fluid_pan_tab[(int) (c + 500)]; + } +} + +/* + * fluid_concave + */ +fluid_real_t +fluid_concave(fluid_real_t val) +{ + if (val < 0) { + return 0; + } else if (val > 127) { + return 1; + } + return fluid_concave_tab[(int) val]; +} + +/* + * fluid_convex + */ +fluid_real_t +fluid_convex(fluid_real_t val) +{ + if (val < 0) { + return 0; + } else if (val > 127) { + return 1; + } + return fluid_convex_tab[(int) val]; +} |