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132 lines
4 KiB
C
132 lines
4 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 (tremolo.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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#include <string/stdstring.h>
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#define sqr(a) ((a) * (a))
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struct tremolo_core
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{
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float *wavetable;
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float freq;
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float depth;
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int index;
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int maxindex;
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};
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struct tremolo
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{
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struct tremolo_core left, right;
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};
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static void tremolo_free(void *data)
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{
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struct tremolo *tre = (struct tremolo*)data;
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free(tre->left.wavetable);
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free(tre->right.wavetable);
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free(data);
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}
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static void tremolocore_init(struct tremolo_core *core,float depth,int samplerate,float freq)
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{
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double env;
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unsigned i;
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const double offset = 1. - depth / 2.;
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core->index = 0;
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core->maxindex = samplerate / freq;
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core->wavetable = malloc(core->maxindex * sizeof(float));
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memset(core->wavetable, 0, core->maxindex * sizeof(float));
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for (i = 0; i < core->maxindex; i++)
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{
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env = freq * i / samplerate;
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env = sin((M_PI*2) * fmod(env + 0.25, 1.0));
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core->wavetable[i] = env * (1 - fabs(offset)) + offset;
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}
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}
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float tremolocore_core(struct tremolo_core *core,float in)
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{
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core->index = core->index % core->maxindex;
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return in * core->wavetable[core->index++];
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}
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static void tremolo_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;
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struct tremolo *tre = (struct tremolo*)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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float in[2] = { out[0], out[1] };
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out[0] = tremolocore_core(&tre->left, in[0]);
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out[1] = tremolocore_core(&tre->right, in[1]);
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}
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}
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static void *tremolo_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 freq, depth;
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struct tremolo *tre = (struct tremolo*)calloc(1, sizeof(*tre));
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if (!tre)
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return NULL;
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config->get_float(userdata, "freq", &freq,4.0f);
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config->get_float(userdata, "depth", &depth, 0.9f);
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tremolocore_init(&tre->left,depth,info->input_rate,freq);
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tremolocore_init(&tre->right,depth,info->input_rate,freq);
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return tre;
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}
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static const struct dspfilter_implementation tremolo_plug = {
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tremolo_init,
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tremolo_process,
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tremolo_free,
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DSPFILTER_API_VERSION,
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"Tremolo",
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"tremolo",
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};
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#ifdef HAVE_FILTERS_BUILTIN
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#define dspfilter_get_implementation tremolo_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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return &tremolo_plug;
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}
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#undef dspfilter_get_implementation
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