mirror of
https://github.com/CTCaer/RetroArch.git
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140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
/* RetroArch - A frontend for libretro.
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* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
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* Copyright (C) 2014 - Brad Miller
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*
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* RetroArch is free software: you can redistribute it and/or modify it under the terms
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* of the GNU General Public License as published by the Free Software Found-
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* ation, either version 3 of the License, or (at your option) any later version.
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*
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* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with RetroArch.
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* If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "dspfilter.h"
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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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#define wahwahlfoskipsamples 30
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#ifndef M_PI
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#define M_PI 3.1415926535897932384626433832795
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#endif
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struct wahwah_data
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{
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float phase;
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float lfoskip;
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float b0, b1, b2, a0, a1, a2;
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float freq, startphase;
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float depth, freqofs, res;
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unsigned long skipcount;
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struct
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{
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float xn1, xn2, yn1, yn2;
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} l, r;
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};
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static void wahwah_free(void *data)
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{
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free(data);
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}
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static void wahwah_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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struct wahwah_data *wah = (struct wahwah_data*)data;
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output->samples = input->samples;
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output->frames = input->frames;
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float *out = output->samples;
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for (i = 0; i < input->frames; i++, out += 2)
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{
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float in[2] = { out[0], out[1] };
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if ((wah->skipcount++ % wahwahlfoskipsamples) == 0)
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{
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float frequency = (1.0 + cos(wah->skipcount * wah->lfoskip + wah->phase)) / 2.0;
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frequency = frequency * wah->depth * (1.0 - wah->freqofs) + wah->freqofs;
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frequency = exp((frequency - 1.0) * 6.0);
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float omega = M_PI * frequency;
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float sn = sin(omega);
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float cs = cos(omega);
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float alpha = sn / (2.0 * wah->res);
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wah->b0 = (1.0 - cs) / 2.0;
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wah->b1 = 1.0 - cs;
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wah->b2 = (1.0 - cs) / 2.0;
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wah->a0 = 1.0 + alpha;
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wah->a1 = -2.0 * cs;
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wah->a2 = 1.0 - alpha;
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}
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float 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;
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float 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;
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wah->l.xn2 = wah->l.xn1;
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wah->l.xn1 = in[0];
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wah->l.yn2 = wah->l.yn1;
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wah->l.yn1 = out_l;
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wah->r.xn2 = wah->r.xn1;
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wah->r.xn1 = in[1];
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wah->r.yn2 = wah->r.yn1;
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wah->r.yn1 = out_r;
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out[0] = out_l;
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out[1] = out_r;
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}
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}
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static void *wahwah_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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struct wahwah_data *wah = (struct wahwah_data*)calloc(1, sizeof(*wah));
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if (!wah)
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return NULL;
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config->get_float(userdata, "lfo_freq", &wah->freq, 1.5f);
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config->get_float(userdata, "lfo_start_phase", &wah->startphase, 0.0f);
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config->get_float(userdata, "freq_offset", &wah->freqofs, 0.3f);
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config->get_float(userdata, "depth", &wah->depth, 0.7f);
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config->get_float(userdata, "resonance", &wah->res, 2.5f);
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wah->lfoskip = wah->freq * 2.0 * M_PI / info->input_rate;
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wah->phase = wah->startphase * M_PI / 180.0;
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return wah;
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}
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static const struct dspfilter_implementation wahwah_plug = {
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wahwah_init,
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wahwah_process,
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wahwah_free,
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DSPFILTER_API_VERSION,
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"Wah-Wah",
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"wahwah",
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};
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#ifdef HAVE_FILTERS_BUILTIN
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#define dspfilter_get_implementation wahwah_dspfilter_get_implementation
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#endif
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const struct dspfilter_implementation *dspfilter_get_implementation(dspfilter_simd_mask_t mask)
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{
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(void)mask;
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return &wahwah_plug;
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}
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#undef dspfilter_get_implementation
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