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Diffstat (limited to 'src/include/wdatutil.h')
| -rw-r--r-- | src/include/wdatutil.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/include/wdatutil.h b/src/include/wdatutil.h new file mode 100644 index 0000000..9a0810a --- /dev/null +++ b/src/include/wdatutil.h @@ -0,0 +1,141 @@ +/* + Code to generate wavedata dl containing pre-calculated wavetables. + Copyright 2011 David Robillard + Copyright 2003 Mike Rawes + + This is free software: you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This software 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 General Public License + along with this software. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef blop_wdatutil_h +#define blop_wdatutil_h + +#include <stdio.h> +#include <stdint.h> +#include "math_func.h" +#include "wavedata.h" + +#define WAVE_TYPE_COUNT 3 + +extern const char* wave_names[]; +extern const char* wave_descriptions[]; +extern unsigned long wave_first_harmonics[]; +extern unsigned long wave_harmonic_intervals[]; + +/** Get actual maximum harmonic from given harmonic, h, and wavetype, w */ +#define ACTUAL_HARM(h, w) h - (h - wave_first_harmonics[w]) % wave_harmonic_intervals[w] + +/** Get minimum harmonic content in given wavetype, w */ +#define MIN_HARM(w) wave_first_harmonics[w] + +/** Get minimum extra harmonic content possible in given wavetype, w */ +#define MIN_EXTRA_HARM(w) wave_harmonic_intervals[w] + +/** Get frequency from MIDI note, n */ +#define FREQ_FROM_NOTE(n) 6.875f * POWF(2.0f, (float)(n + 3) / 12.0f) + +/** Get max harmonic from given frequency, f, at sample rate, r */ +#define HARM_FROM_FREQ(f, r) (unsigned long)((float)r / f / 2.0f) + +/* + * A single wavetable will have a range of pitches at which their samples + * may be played back. + * + * The upper bound is determined by the maximum harmonic present in the + * waveform - above this frequency, the higher harmonics will alias. + * + * The lower bound is chosen to be the higher bound of the previous wavetable + * (or a pre-defined limit if there is no such table). + */ + +typedef enum { + SAW, + SQUARE, + PARABOLA +} Wavetype; + +#ifdef __cplusplus +extern "C" { +#endif + +/******************************************************************************* + * Description: Allocate new wavedata struct + * + * Arguments: sample_rate Sample rate to use when generating data + * + * Returns: Pointer to wavedata on success + * NULL (0) on failure + * + * Notes: No wavetables are allocated. Use wavedata_add_table + ******************************************************************************/ +Wavedata* wavedata_new(double sample_rate); + +/******************************************************************************* + * Description: Destroy allocated wavedata and any tables + * + * Arguments: w Wavedata struct to cleanup + ******************************************************************************/ +void wavedata_cleanup(Wavedata* w); + +/******************************************************************************* + * Description: Add new wavetable information to wavedata file object + * + * Arguments: w Wavedata to add table to + * sample_count Number of samples in wavetable + * harmonics Maximum harmonics present in table + * + * Returns: 0 on success + * -1 otherwise + ******************************************************************************/ +int wavedata_add_table(Wavedata* w, + uint32_t sample_count, + unsigned long harmonics); + +/******************************************************************************* + * Description: Initialise all wavetables in wavedata with a waveform + * generated from Fourier series. + * + * Arguments: w Wavedata to generate data for + * wavetype Wavetype to generate + * gibbs_comp Compensation for Gibbs' effect: + * 0.0: none (wave will overshoot) + * 1.0: full (wave will not overshoot) + * + * Notes: Compensation for Gibbs' Effect will reduce the degree + * of overshoot and ripple at the transitions. A value of 1.0 + * will pretty much eliminate it. + ******************************************************************************/ +void wavedata_generate_tables(Wavedata* w, + Wavetype wavetype, + float gibbs_comp); + +/******************************************************************************* + * Description: Write wavedata as a c header file + * + * Arguments: w Wavedata to write + * wdat_fp Pointer to output file + * prefix Prefix to use in declarations. If this is null + * declarations are prefixed with 'wdat'. + * + * Returns: 0 on success + * -1 otherwise + ******************************************************************************/ +int wavedata_write(Wavedata* w, + FILE* wdat_fp, + const char* prefix); + +#ifdef __cplusplus +} /* extern "C" { */ +#endif + +#endif /* blop_wdatutil_h */ |