| 1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * |
| 3 | * --------------------------------------------------------------------------------------- |
| 4 | * The following license statement only applies to this file (vibrato.c). |
| 5 | * --------------------------------------------------------------------------------------- |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, |
| 8 | * to any person obtaining a copy of this software and associated documentation files (the "Software"), |
| 9 | * to deal in the Software without restriction, including without limitation the rights to |
| 10 | * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| 11 | * and to permit persons to whom the Software is furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
| 16 | * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| 19 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 20 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 21 | */ |
| 22 | |
| 23 | #include <math.h> |
| 24 | #include <stdlib.h> |
| 25 | #include <string.h> |
| 26 | |
| 27 | #include <retro_miscellaneous.h> |
| 28 | #include <libretro_dspfilter.h> |
| 29 | #include <string/stdstring.h> |
| 30 | |
| 31 | #define sqr(a) ((a) * (a)) |
| 32 | |
| 33 | #define VIBRATO_BASE_DELAY_SEC 0.002f /* 2 ms */ |
| 34 | #define VIBRATO_FREQUENCY_DEFAULT_HZ 2.0f |
| 35 | #define VIBRATO_FREQUENCY_MAX_HZ 14.0f |
| 36 | #define VIBRATO_DEPTH_DEFAULT_PERCENT 50.0f |
| 37 | #define VIBRATO_ADD_DELAY 3 |
| 38 | |
| 39 | static float hermite_interp(float x, float *y) |
| 40 | { |
| 41 | float c0 = y[1]; |
| 42 | float c1 = (1.0f / 2.0f) * (y[2] - y[0]); |
| 43 | float c2 = (y[0] - (5.0f / 2.0f) * y[1]) + (2.0f * y[2] - (1.0f / 2.0f) * y[3]); |
| 44 | float c3 = (1.0f / 2.0f) * (y[3] - y[0]) + (3.0f / 2.0f) * (y[1] - y[2]); |
| 45 | return ((c3 * x + c2) * x + c1) * x + c0; |
| 46 | } |
| 47 | |
| 48 | struct vibrato_core |
| 49 | { |
| 50 | float* buffer; |
| 51 | float freq; |
| 52 | float samplerate; |
| 53 | float depth; |
| 54 | int phase; |
| 55 | int writeindex; |
| 56 | int size; |
| 57 | }; |
| 58 | |
| 59 | struct vibrato |
| 60 | { |
| 61 | struct vibrato_core left, right; |
| 62 | }; |
| 63 | |
| 64 | static void vibrato_free(void *data) |
| 65 | { |
| 66 | struct vibrato *vib = (struct vibrato*)data; |
| 67 | free(vib->left.buffer); |
| 68 | free(vib->right.buffer); |
| 69 | free(data); |
| 70 | } |
| 71 | |
| 72 | static void vibratocore_init(struct vibrato_core *core,float depth,int samplerate,float freq) |
| 73 | { |
| 74 | core->size = VIBRATO_BASE_DELAY_SEC * samplerate * 2; |
| 75 | core->buffer = malloc((core->size + VIBRATO_ADD_DELAY) * sizeof(float)); |
| 76 | memset(core->buffer, 0, (core->size + VIBRATO_ADD_DELAY) * sizeof(float)); |
| 77 | core->samplerate = samplerate; |
| 78 | core->freq = freq; |
| 79 | core->depth = depth; |
| 80 | core->phase = 0; |
| 81 | core->writeindex = 0; |
| 82 | } |
| 83 | |
| 84 | float vibratocore_core(struct vibrato_core *core,float in) |
| 85 | { |
| 86 | int ipart; |
| 87 | float delay, readindex, fpart, value; |
| 88 | float M = core->freq / core->samplerate; |
| 89 | int maxphase = core->samplerate / core->freq; |
| 90 | float lfo = sin(M * 2. * M_PI * core->phase++); |
| 91 | int maxdelay = VIBRATO_BASE_DELAY_SEC * core->samplerate; |
| 92 | core->phase = core->phase % maxphase; |
| 93 | lfo = (lfo + 1) * 1.; // transform from [-1; 1] to [0; 1] |
| 94 | delay = lfo * core->depth * maxdelay; |
| 95 | delay += VIBRATO_ADD_DELAY; |
| 96 | readindex = core->writeindex - 1 - delay; |
| 97 | while (readindex < 0) |
| 98 | readindex += core->size; |
| 99 | while (readindex >= core->size) |
| 100 | readindex -= core->size; |
| 101 | ipart = (int)readindex; /* Integer part of the delay */ |
| 102 | fpart = readindex - ipart; /* fractional part of the delay */ |
| 103 | value = hermite_interp(fpart, &(core->buffer[ipart])); |
| 104 | core->buffer[core->writeindex] = in; |
| 105 | if (core->writeindex < VIBRATO_ADD_DELAY) |
| 106 | core->buffer[core->size + core->writeindex] = in; |
| 107 | core->writeindex++; |
| 108 | if (core->writeindex == core->size) |
| 109 | core->writeindex = 0; |
| 110 | return value; |
| 111 | } |
| 112 | |
| 113 | static void vibrato_process(void *data, |
| 114 | struct dspfilter_output *output, |
| 115 | const struct dspfilter_input *input) |
| 116 | { |
| 117 | unsigned i; |
| 118 | float *out; |
| 119 | struct vibrato *vib = (struct vibrato*)data; |
| 120 | |
| 121 | output->samples = input->samples; |
| 122 | output->frames = input->frames; |
| 123 | out = output->samples; |
| 124 | |
| 125 | for (i = 0; i < input->frames; i++, out += 2) |
| 126 | { |
| 127 | float in[2] = { out[0], out[1] }; |
| 128 | out[0] = vibratocore_core(&vib->left, in[0]); |
| 129 | out[1] = vibratocore_core(&vib->right, in[1]); |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | static void *vibrato_init(const struct dspfilter_info *info, |
| 134 | const struct dspfilter_config *config, void *userdata) |
| 135 | { |
| 136 | float freq, depth; |
| 137 | struct vibrato *vib = (struct vibrato*)calloc(1, sizeof(*vib)); |
| 138 | if (!vib) |
| 139 | return NULL; |
| 140 | |
| 141 | config->get_float(userdata, "freq", &freq,5.0f); |
| 142 | config->get_float(userdata, "depth", &depth, 0.5f); |
| 143 | vibratocore_init(&vib->left,depth,info->input_rate,freq); |
| 144 | vibratocore_init(&vib->right,depth,info->input_rate,freq); |
| 145 | return vib; |
| 146 | } |
| 147 | |
| 148 | static const struct dspfilter_implementation vibrato_plug = { |
| 149 | vibrato_init, |
| 150 | vibrato_process, |
| 151 | vibrato_free, |
| 152 | |
| 153 | DSPFILTER_API_VERSION, |
| 154 | "Vibrato", |
| 155 | "vibrato", |
| 156 | }; |
| 157 | |
| 158 | #ifdef HAVE_FILTERS_BUILTIN |
| 159 | #define dspfilter_get_implementation vibrato_dspfilter_get_implementation |
| 160 | #endif |
| 161 | |
| 162 | const struct dspfilter_implementation *dspfilter_get_implementation(dspfilter_simd_mask_t mask) |
| 163 | { |
| 164 | return &vibrato_plug; |
| 165 | } |
| 166 | |
| 167 | #undef dspfilter_get_implementation |