| 1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * |
| 3 | * --------------------------------------------------------------------------------------- |
| 4 | * The following license statement only applies to this file (wahwah.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 | |
| 30 | #define WAHWAH_LFO_SKIP_SAMPLES 30 |
| 31 | |
| 32 | struct wahwah_data |
| 33 | { |
| 34 | float phase; |
| 35 | float lfoskip; |
| 36 | float b0, b1, b2, a0, a1, a2; |
| 37 | float freq, startphase; |
| 38 | float depth, freqofs, res; |
| 39 | unsigned long skipcount; |
| 40 | |
| 41 | struct |
| 42 | { |
| 43 | float xn1, xn2, yn1, yn2; |
| 44 | } l, r; |
| 45 | }; |
| 46 | |
| 47 | static void wahwah_free(void *data) |
| 48 | { |
| 49 | if (data) |
| 50 | free(data); |
| 51 | } |
| 52 | |
| 53 | static void wahwah_process(void *data, struct dspfilter_output *output, |
| 54 | const struct dspfilter_input *input) |
| 55 | { |
| 56 | unsigned i; |
| 57 | struct wahwah_data *wah = (struct wahwah_data*)data; |
| 58 | float *out = output->samples; |
| 59 | |
| 60 | output->samples = input->samples; |
| 61 | output->frames = input->frames; |
| 62 | |
| 63 | for (i = 0; i < input->frames; i++, out += 2) |
| 64 | { |
| 65 | float out_l, out_r; |
| 66 | float in[2] = { out[0], out[1] }; |
| 67 | |
| 68 | if ((wah->skipcount++ % WAHWAH_LFO_SKIP_SAMPLES) == 0) |
| 69 | { |
| 70 | float omega, sn, cs, alpha; |
| 71 | float frequency = (1.0f + cos(wah->skipcount * wah->lfoskip + wah->phase)) / 2.0f; |
| 72 | |
| 73 | frequency = frequency * wah->depth * (1.0f - wah->freqofs) + wah->freqofs; |
| 74 | frequency = exp((frequency - 1.0f) * 6.0f); |
| 75 | |
| 76 | omega = M_PI * frequency; |
| 77 | sn = sin(omega); |
| 78 | cs = cos(omega); |
| 79 | alpha = sn / (2.0f * wah->res); |
| 80 | |
| 81 | wah->b0 = (1.0f - cs) / 2.0f; |
| 82 | wah->b1 = 1.0f - cs; |
| 83 | wah->b2 = (1.0f - cs) / 2.0f; |
| 84 | wah->a0 = 1.0f + alpha; |
| 85 | wah->a1 = -2.0f * cs; |
| 86 | wah->a2 = 1.0f - alpha; |
| 87 | } |
| 88 | |
| 89 | out_l = (wah->b0 * in[0] + wah->b1 * wah->l.xn1 + wah->b2 * wah->l.xn2 - wah->a1 * wah->l.yn1 - wah->a2 * wah->l.yn2) / wah->a0; |
| 90 | out_r = (wah->b0 * in[1] + wah->b1 * wah->r.xn1 + wah->b2 * wah->r.xn2 - wah->a1 * wah->r.yn1 - wah->a2 * wah->r.yn2) / wah->a0; |
| 91 | |
| 92 | wah->l.xn2 = wah->l.xn1; |
| 93 | wah->l.xn1 = in[0]; |
| 94 | wah->l.yn2 = wah->l.yn1; |
| 95 | wah->l.yn1 = out_l; |
| 96 | |
| 97 | wah->r.xn2 = wah->r.xn1; |
| 98 | wah->r.xn1 = in[1]; |
| 99 | wah->r.yn2 = wah->r.yn1; |
| 100 | wah->r.yn1 = out_r; |
| 101 | |
| 102 | out[0] = out_l; |
| 103 | out[1] = out_r; |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | static void *wahwah_init(const struct dspfilter_info *info, |
| 108 | const struct dspfilter_config *config, void *userdata) |
| 109 | { |
| 110 | struct wahwah_data *wah = (struct wahwah_data*)calloc(1, sizeof(*wah)); |
| 111 | if (!wah) |
| 112 | return NULL; |
| 113 | |
| 114 | config->get_float(userdata, "lfo_freq", &wah->freq, 1.5f); |
| 115 | config->get_float(userdata, "lfo_start_phase", &wah->startphase, 0.0f); |
| 116 | config->get_float(userdata, "freq_offset", &wah->freqofs, 0.3f); |
| 117 | config->get_float(userdata, "depth", &wah->depth, 0.7f); |
| 118 | config->get_float(userdata, "resonance", &wah->res, 2.5f); |
| 119 | |
| 120 | wah->lfoskip = wah->freq * 2.0f * M_PI / info->input_rate; |
| 121 | wah->phase = wah->startphase * M_PI / 180.0f; |
| 122 | |
| 123 | return wah; |
| 124 | } |
| 125 | |
| 126 | static const struct dspfilter_implementation wahwah_plug = { |
| 127 | wahwah_init, |
| 128 | wahwah_process, |
| 129 | wahwah_free, |
| 130 | |
| 131 | DSPFILTER_API_VERSION, |
| 132 | "Wah-Wah", |
| 133 | "wahwah", |
| 134 | }; |
| 135 | |
| 136 | #ifdef HAVE_FILTERS_BUILTIN |
| 137 | #define dspfilter_get_implementation wahwah_dspfilter_get_implementation |
| 138 | #endif |
| 139 | |
| 140 | const struct dspfilter_implementation * |
| 141 | dspfilter_get_implementation(dspfilter_simd_mask_t mask) |
| 142 | { |
| 143 | (void)mask; |
| 144 | return &wahwah_plug; |
| 145 | } |
| 146 | |
| 147 | #undef dspfilter_get_implementation |