156 lines
5.2 KiB
C
156 lines
5.2 KiB
C
/* Copyright (C) 2010-2020 The RetroArch team
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*
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* ---------------------------------------------------------------------------------------
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* The following license statement only applies to this file (chorus.c).
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* ---------------------------------------------------------------------------------------
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*
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* Permission is hereby granted, free of charge,
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* to any person obtaining a copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include <retro_miscellaneous.h>
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#include <libretro_dspfilter.h>
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#define CHORUS_MAX_DELAY 4096
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#define CHORUS_DELAY_MASK (CHORUS_MAX_DELAY - 1)
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struct chorus_data
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{
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float old[2][CHORUS_MAX_DELAY];
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float delay;
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float depth;
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float input_rate;
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float mix_dry;
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float mix_wet;
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unsigned old_ptr;
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unsigned lfo_ptr;
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unsigned lfo_period;
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};
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static void chorus_free(void *data)
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{
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if (data)
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free(data);
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}
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static void chorus_process(void *data, struct dspfilter_output *output,
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const struct dspfilter_input *input)
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{
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unsigned i;
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float *out = NULL;
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struct chorus_data *ch = (struct chorus_data*)data;
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output->samples = input->samples;
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output->frames = input->frames;
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out = output->samples;
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for (i = 0; i < input->frames; i++, out += 2)
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{
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unsigned delay_int;
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float delay_frac, l_a, l_b, r_a, r_b;
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float chorus_l, chorus_r;
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float in[2] = { out[0], out[1] };
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float delay = ch->delay + ch->depth * sin((2.0 * M_PI * ch->lfo_ptr++) / ch->lfo_period);
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delay *= ch->input_rate;
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if (ch->lfo_ptr >= ch->lfo_period)
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ch->lfo_ptr = 0;
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delay_int = (unsigned)delay;
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if (delay_int >= CHORUS_MAX_DELAY - 1)
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delay_int = CHORUS_MAX_DELAY - 2;
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delay_frac = delay - delay_int;
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ch->old[0][ch->old_ptr] = in[0];
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ch->old[1][ch->old_ptr] = in[1];
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l_a = ch->old[0][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK];
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l_b = ch->old[0][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK];
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r_a = ch->old[1][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK];
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r_b = ch->old[1][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK];
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/* Lerp introduces aliasing of the chorus component,
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* but doing full polyphase here is probably overkill. */
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chorus_l = l_a * (1.0f - delay_frac) + l_b * delay_frac;
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chorus_r = r_a * (1.0f - delay_frac) + r_b * delay_frac;
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out[0] = ch->mix_dry * in[0] + ch->mix_wet * chorus_l;
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out[1] = ch->mix_dry * in[1] + ch->mix_wet * chorus_r;
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ch->old_ptr = (ch->old_ptr + 1) & CHORUS_DELAY_MASK;
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}
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}
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static void *chorus_init(const struct dspfilter_info *info,
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const struct dspfilter_config *config, void *userdata)
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{
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float delay, depth, lfo_freq, drywet;
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struct chorus_data *ch = (struct chorus_data*)calloc(1, sizeof(*ch));
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if (!ch)
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return NULL;
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config->get_float(userdata, "delay_ms", &delay, 25.0f);
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config->get_float(userdata, "depth_ms", &depth, 1.0f);
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config->get_float(userdata, "lfo_freq", &lfo_freq, 0.5f);
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config->get_float(userdata, "drywet", &drywet, 0.8f);
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delay /= 1000.0f;
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depth /= 1000.0f;
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if (depth > delay)
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depth = delay;
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if (drywet < 0.0f)
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drywet = 0.0f;
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else if (drywet > 1.0f)
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drywet = 1.0f;
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ch->mix_dry = 1.0f - 0.5f * drywet;
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ch->mix_wet = 0.5f * drywet;
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ch->delay = delay;
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ch->depth = depth;
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ch->lfo_period = (1.0f / lfo_freq) * info->input_rate;
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ch->input_rate = info->input_rate;
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if (!ch->lfo_period)
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ch->lfo_period = 1;
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return ch;
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}
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static const struct dspfilter_implementation chorus_plug = {
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chorus_init,
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chorus_process,
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chorus_free,
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DSPFILTER_API_VERSION,
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"Chorus",
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"chorus",
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};
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#ifdef HAVE_FILTERS_BUILTIN
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#define dspfilter_get_implementation chorus_dspfilter_get_implementation
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#endif
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const struct dspfilter_implementation *
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dspfilter_get_implementation(dspfilter_simd_mask_t mask) { return &chorus_plug; }
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#undef dspfilter_get_implementation
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