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/* Copyright (C) 2010-2020 The RetroArch team
*
* ---------------------------------------------------------------------------------------
* The following license statement only applies to this file (phaser.c).
* ---------------------------------------------------------------------------------------
*
* Permission is hereby granted, free of charge,
* to any person obtaining a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <retro_miscellaneous.h>
#include <libretro_dspfilter.h>
#define PHASER_LFO_SHAPE 4.0
#define PHASER_LFO_SKIP_SAMPLES 20
struct phaser_data
{
float freq;
float startphase;
float fb;
float depth;
float drywet;
float old[2][24];
float gain;
float fbout[2];
float lfoskip;
float phase;
int stages;
unsigned long skipcount;
};
static void phaser_free(void *data)
{
free(data);
}
static void phaser_process(void *data, struct dspfilter_output *output,
const struct dspfilter_input *input)
{
unsigned i, c;
int s;
float m[2], tmp[2];
struct phaser_data *ph = (struct phaser_data*)data;
float *out = output->samples;
output->samples = input->samples;
output->frames = input->frames;
for (i = 0; i < input->frames; i++, out += 2)
{
float in[2] = { out[0], out[1] };
for (c = 0; c < 2; c++)
m[c] = in[c] + ph->fbout[c] * ph->fb * 0.01f;
if ((ph->skipcount++ % PHASER_LFO_SKIP_SAMPLES) == 0)
{
ph->gain = 0.5 * (1.0 + cos(ph->skipcount * ph->lfoskip + ph->phase));
ph->gain = (exp(ph->gain * PHASER_LFO_SHAPE) - 1.0) / (exp(PHASER_LFO_SHAPE) - 1);
ph->gain = 1.0 - ph->gain * ph->depth;
}
for (s = 0; s < ph->stages; s++)
{
for (c = 0; c < 2; c++)
{
tmp[c] = ph->old[c][s];
ph->old[c][s] = ph->gain * tmp[c] + m[c];
m[c] = tmp[c] - ph->gain * ph->old[c][s];
}
}
for (c = 0; c < 2; c++)
{
ph->fbout[c] = m[c];
out[c] = m[c] * ph->drywet + in[c] * (1.0f - ph->drywet);
}
}
}
static void *phaser_init(const struct dspfilter_info *info,
const struct dspfilter_config *config, void *userdata)
{
float lfo_freq, lfo_start_phase;
struct phaser_data *ph = (struct phaser_data*)calloc(1, sizeof(*ph));
if (!ph)
return NULL;
config->get_float(userdata, "lfo_freq", &lfo_freq, 0.4f);
config->get_float(userdata, "lfo_start_phase", &lfo_start_phase, 0.0f);
config->get_float(userdata, "feedback", &ph->fb, 0.0f);
config->get_float(userdata, "depth", &ph->depth, 0.4f);
config->get_float(userdata, "dry_wet", &ph->drywet, 0.5f);
config->get_int(userdata, "stages", &ph->stages, 2);
if (ph->stages < 1)
ph->stages = 1;
else if (ph->stages > 24)
ph->stages = 24;
ph->lfoskip = lfo_freq * 2.0 * M_PI / info->input_rate;
ph->phase = lfo_start_phase * M_PI / 180.0;
return ph;
}
static const struct dspfilter_implementation phaser_plug = {
phaser_init,
phaser_process,
phaser_free,
DSPFILTER_API_VERSION,
"Phaser",
"phaser",
};
#ifdef HAVE_FILTERS_BUILTIN
#define dspfilter_get_implementation phaser_dspfilter_get_implementation
#endif
const struct dspfilter_implementation *dspfilter_get_implementation(dspfilter_simd_mask_t mask)
{
return &phaser_plug;
}
#undef dspfilter_get_implementation
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