Add Chorus DSP.

This commit is contained in:
Themaister 2014-06-01 14:30:39 +02:00
parent d8c8f3a139
commit cea2b160cd
4 changed files with 165 additions and 0 deletions

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@ -227,6 +227,7 @@ extern const struct dspfilter_implementation *echo_dspfilter_get_implementation(
extern const struct dspfilter_implementation *phaser_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
extern const struct dspfilter_implementation *wahwah_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
extern const struct dspfilter_implementation *eq_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
extern const struct dspfilter_implementation *chorus_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
static const dspfilter_get_implementation_t dsp_plugs_builtin[] = {
panning_dspfilter_get_implementation,
@ -235,6 +236,7 @@ static const dspfilter_get_implementation_t dsp_plugs_builtin[] = {
phaser_dspfilter_get_implementation,
wahwah_dspfilter_get_implementation,
eq_dspfilter_get_implementation,
chorus_dspfilter_get_implementation,
};
static bool append_plugs(rarch_dsp_filter_t *dsp)

14
audio/filters/Chorus.dsp Normal file
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@ -0,0 +1,14 @@
filters = 1
filter0 = chorus
# Controls the base delay of the chorus (milliseconds).
# chorus_delay_ms = 25.0
#
# Controls the depth of the delay. The delay will vary between delay_ms +/- depth_ms.
# chorus_depth_ms = 1.0
#
# Frequency of LFO which controls delay.
# chorus_lfo_freq = 0.5
#
# Controls dry/wet-ness of effect. 1.0 = full chorus, 0.0 = no chorus.
# chorus_drywet = 0.8

148
audio/filters/chorus.c Normal file
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@ -0,0 +1,148 @@
/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
*
* RetroArch is free software: you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include "dspfilter.h"
#include <math.h>
#include <stdlib.h>
#include <string.h>
#ifndef M_PI
#define M_PI 3.1415926535897932384626433832795
#endif
#define CHORUS_MAX_DELAY 4096
#define CHORUS_DELAY_MASK (CHORUS_MAX_DELAY - 1)
struct chorus_data
{
float old[2][CHORUS_MAX_DELAY];
unsigned old_ptr;
float delay;
float depth;
float input_rate;
float mix_dry;
float mix_wet;
unsigned lfo_ptr;
unsigned lfo_period;
};
static void chorus_free(void *data)
{
free(data);
}
static void chorus_process(void *data, struct dspfilter_output *output,
const struct dspfilter_input *input)
{
unsigned i;
struct chorus_data *ch = (struct chorus_data*)data;
output->samples = input->samples;
output->frames = input->frames;
float *out = output->samples;
for (i = 0; i < input->frames; i++, out += 2)
{
float in[2] = { out[0], out[1] };
float delay = ch->delay + ch->depth * sin((2.0 * M_PI * ch->lfo_ptr++) / ch->lfo_period);
delay *= ch->input_rate;
if (ch->lfo_ptr >= ch->lfo_period)
ch->lfo_ptr = 0;
unsigned delay_int = (unsigned)delay;
if (delay_int >= CHORUS_MAX_DELAY - 1)
delay_int = CHORUS_MAX_DELAY - 2;
float delay_frac = delay - delay_int;
ch->old[0][ch->old_ptr] = in[0];
ch->old[1][ch->old_ptr] = in[1];
float l_a = ch->old[0][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK];
float l_b = ch->old[0][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK];
float r_a = ch->old[1][(ch->old_ptr - delay_int - 0) & CHORUS_DELAY_MASK];
float r_b = ch->old[1][(ch->old_ptr - delay_int - 1) & CHORUS_DELAY_MASK];
// Lerp introduces aliasing of the chorus component, but doing full polyphase here is probably overkill.
float chorus_l = l_a * (1.0f - delay_frac) + l_b * delay_frac;
float chorus_r = r_a * (1.0f - delay_frac) + r_b * delay_frac;
out[0] = ch->mix_dry * in[0] + ch->mix_wet * chorus_l;
out[1] = ch->mix_dry * in[1] + ch->mix_wet * chorus_r;
ch->old_ptr = (ch->old_ptr + 1) & CHORUS_DELAY_MASK;
ch->lfo_ptr = (ch->lfo_ptr + 1) % ch->lfo_period;
}
}
static void *chorus_init(const struct dspfilter_info *info,
const struct dspfilter_config *config, void *userdata)
{
struct chorus_data *ch = (struct chorus_data*)calloc(1, sizeof(*ch));
if (!ch)
return NULL;
float delay, depth, lfo_freq, drywet;
config->get_float(userdata, "delay_ms", &delay, 25.0f);
config->get_float(userdata, "depth_ms", &depth, 1.0f);
config->get_float(userdata, "lfo_freq", &lfo_freq, 0.5f);
config->get_float(userdata, "drywet", &drywet, 0.8f);
delay /= 1000.0f;
depth /= 1000.0f;
if (depth > delay)
depth = delay;
if (drywet < 0.0f)
drywet = 0.0f;
else if (drywet > 1.0f)
drywet = 1.0f;
ch->mix_dry = 1.0f - 0.5f * drywet;
ch->mix_wet = 0.5f * drywet;
ch->delay = delay;
ch->depth = depth;
ch->lfo_period = (1.0f / lfo_freq) * info->input_rate;
ch->input_rate = info->input_rate;
if (!ch->lfo_period)
ch->lfo_period = 1;
return ch;
}
static const struct dspfilter_implementation chorus_plug = {
chorus_init,
chorus_process,
chorus_free,
DSPFILTER_API_VERSION,
"Chorus",
"chorus",
};
#ifdef HAVE_FILTERS_BUILTIN
#define dspfilter_get_implementation chorus_dspfilter_get_implementation
#endif
const struct dspfilter_implementation *dspfilter_get_implementation(dspfilter_simd_mask_t mask)
{
(void)mask;
return &chorus_plug;
}
#undef dspfilter_get_implementation

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@ -481,6 +481,7 @@ FILTERS
#include "../audio/filters/echo.c"
#include "../audio/filters/eq.c"
#include "../audio/filters/chorus.c"
#include "../audio/filters/iir.c"
#include "../audio/filters/panning.c"
#include "../audio/filters/phaser.c"