| 1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * |
| 3 | * --------------------------------------------------------------------------------------- |
| 4 | * The following license statement only applies to this file (chorus.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 CHORUS_MAX_DELAY 4096 |
| 31 | #define CHORUS_DELAY_MASK (CHORUS_MAX_DELAY - 1) |
| 32 | |
| 33 | struct chorus_data |
| 34 | { |
| 35 | float old[2][CHORUS_MAX_DELAY]; |
| 36 | float delay; |
| 37 | float depth; |
| 38 | float input_rate; |
| 39 | float mix_dry; |
| 40 | float mix_wet; |
| 41 | unsigned old_ptr; |
| 42 | unsigned lfo_ptr; |
| 43 | unsigned lfo_period; |
| 44 | }; |
| 45 | |
| 46 | static void chorus_free(void *data) |
| 47 | { |
| 48 | if (data) |
| 49 | free(data); |
| 50 | } |
| 51 | |
| 52 | static void chorus_process(void *data, struct dspfilter_output *output, |
| 53 | const struct dspfilter_input *input) |
| 54 | { |
| 55 | unsigned i; |
| 56 | float *out = NULL; |
| 57 | struct chorus_data *ch = (struct chorus_data*)data; |
| 58 | |
| 59 | output->samples = input->samples; |
| 60 | output->frames = input->frames; |
| 61 | out = output->samples; |
| 62 | |
| 63 | for (i = 0; i < input->frames; i++, out += 2) |
| 64 | { |
| 65 | unsigned delay_int; |
| 66 | float delay_frac, l_a, l_b, r_a, r_b; |
| 67 | float chorus_l, chorus_r; |
| 68 | float in[2] = { out[0], out[1] }; |
| 69 | float delay = ch->delay + ch->depth * sin((2.0 * M_PI * ch->lfo_ptr++) / ch->lfo_period); |
| 70 | |
| 71 | delay *= ch->input_rate; |
| 72 | if (ch->lfo_ptr >= ch->lfo_period) |
| 73 | ch->lfo_ptr = 0; |
| 74 | |
| 75 | delay_int = (unsigned)delay; |
| 76 | |
| 77 | if (delay_int >= CHORUS_MAX_DELAY - 1) |
| 78 | delay_int = CHORUS_MAX_DELAY - 2; |
| 79 | |
| 80 | delay_frac = delay - delay_int; |
| 81 | |
| 82 | ch->old[0][ch->old_ptr] = in[0]; |
| 83 | ch->old[1][ch->old_ptr] = in[1]; |
| 84 | |
| 85 | l_a = ch->old[0][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK]; |
| 86 | l_b = ch->old[0][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK]; |
| 87 | r_a = ch->old[1][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK]; |
| 88 | r_b = ch->old[1][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK]; |
| 89 | |
| 90 | /* Lerp introduces aliasing of the chorus component, |
| 91 | * but doing full polyphase here is probably overkill. */ |
| 92 | chorus_l = l_a * (1.0f - delay_frac) + l_b * delay_frac; |
| 93 | chorus_r = r_a * (1.0f - delay_frac) + r_b * delay_frac; |
| 94 | |
| 95 | out[0] = ch->mix_dry * in[0] + ch->mix_wet * chorus_l; |
| 96 | out[1] = ch->mix_dry * in[1] + ch->mix_wet * chorus_r; |
| 97 | |
| 98 | ch->old_ptr = (ch->old_ptr + 1) & CHORUS_DELAY_MASK; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | static void *chorus_init(const struct dspfilter_info *info, |
| 103 | const struct dspfilter_config *config, void *userdata) |
| 104 | { |
| 105 | float delay, depth, lfo_freq, drywet; |
| 106 | struct chorus_data *ch = (struct chorus_data*)calloc(1, sizeof(*ch)); |
| 107 | if (!ch) |
| 108 | return NULL; |
| 109 | |
| 110 | config->get_float(userdata, "delay_ms", &delay, 25.0f); |
| 111 | config->get_float(userdata, "depth_ms", &depth, 1.0f); |
| 112 | config->get_float(userdata, "lfo_freq", &lfo_freq, 0.5f); |
| 113 | config->get_float(userdata, "drywet", &drywet, 0.8f); |
| 114 | |
| 115 | delay /= 1000.0f; |
| 116 | depth /= 1000.0f; |
| 117 | |
| 118 | if (depth > delay) |
| 119 | depth = delay; |
| 120 | |
| 121 | if (drywet < 0.0f) |
| 122 | drywet = 0.0f; |
| 123 | else if (drywet > 1.0f) |
| 124 | drywet = 1.0f; |
| 125 | |
| 126 | ch->mix_dry = 1.0f - 0.5f * drywet; |
| 127 | ch->mix_wet = 0.5f * drywet; |
| 128 | |
| 129 | ch->delay = delay; |
| 130 | ch->depth = depth; |
| 131 | ch->lfo_period = (1.0f / lfo_freq) * info->input_rate; |
| 132 | ch->input_rate = info->input_rate; |
| 133 | if (!ch->lfo_period) |
| 134 | ch->lfo_period = 1; |
| 135 | return ch; |
| 136 | } |
| 137 | |
| 138 | static const struct dspfilter_implementation chorus_plug = { |
| 139 | chorus_init, |
| 140 | chorus_process, |
| 141 | chorus_free, |
| 142 | |
| 143 | DSPFILTER_API_VERSION, |
| 144 | "Chorus", |
| 145 | "chorus", |
| 146 | }; |
| 147 | |
| 148 | #ifdef HAVE_FILTERS_BUILTIN |
| 149 | #define dspfilter_get_implementation chorus_dspfilter_get_implementation |
| 150 | #endif |
| 151 | |
| 152 | const struct dspfilter_implementation * |
| 153 | dspfilter_get_implementation(dspfilter_simd_mask_t mask) { return &chorus_plug; } |
| 154 | |
| 155 | #undef dspfilter_get_implementation |