diff --git a/audio/dsp_filter.c b/audio/dsp_filter.c
index 66606d233b..939c6ce455 100644
--- a/audio/dsp_filter.c
+++ b/audio/dsp_filter.c
@@ -225,12 +225,14 @@ extern const struct dspfilter_implementation *panning_dspfilter_get_implementati
extern const struct dspfilter_implementation *iir_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
extern const struct dspfilter_implementation *echo_dspfilter_get_implementation(dspfilter_simd_mask_t mask);
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);
static const dspfilter_get_implementation_t dsp_plugs_builtin[] = {
panning_dspfilter_get_implementation,
iir_dspfilter_get_implementation,
echo_dspfilter_get_implementation,
phaser_dspfilter_get_implementation,
+ wahwah_dspfilter_get_implementation,
};
static bool append_plugs(rarch_dsp_filter_t *dsp)
diff --git a/audio/filters/WahWah.dsp b/audio/filters/WahWah.dsp
new file mode 100644
index 0000000000..a4590cc28a
--- /dev/null
+++ b/audio/filters/WahWah.dsp
@@ -0,0 +1,10 @@
+filters = 1
+filter0 = wahwah
+
+# Defaults.
+# lfo_freq = 1.5
+# lfo_start_phase = 0.0
+# freq_offset = 0.3
+# depth = 0.7
+# resonance = 2.5
+
diff --git a/audio/filters/phaser.c b/audio/filters/phaser.c
index 1ea41237a4..76262f56b7 100644
--- a/audio/filters/phaser.c
+++ b/audio/filters/phaser.c
@@ -22,6 +22,10 @@
#define phaserlfoshape 4.0
#define lfoskipsamples 20
+#ifndef M_PI
+#define M_PI 3.1415926535897932384626433832795
+#endif
+
struct phaser_data
{
float freq;
@@ -113,10 +117,6 @@ static void *phaser_init(const struct dspfilter_info *info,
ph->phase = lfo_start_phase * M_PI / 180.0;
return ph;
-
-error:
- free(ph);
- return NULL;
}
static const struct dspfilter_implementation phaser_plug = {
diff --git a/audio/filters/wahwah.c b/audio/filters/wahwah.c
new file mode 100644
index 0000000000..6d05ae8335
--- /dev/null
+++ b/audio/filters/wahwah.c
@@ -0,0 +1,139 @@
+/* RetroArch - A frontend for libretro.
+ * Copyright (C) 2010-2014 - Hans-Kristian Arntzen
+ * Copyright (C) 2014 - Brad Miller
+ *
+ * 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 .
+ */
+
+#include "dspfilter.h"
+#include
+#include
+#include
+
+#define lfoskipsamples 30
+
+#ifndef M_PI
+#define M_PI 3.1415926535897932384626433832795
+#endif
+
+struct wahwah_data
+{
+ float phase;
+ float lfoskip;
+ float b0, b1, b2, a0, a1, a2;
+ float freq, startphase;
+ float depth, freqofs, res;
+ unsigned long skipcount;
+
+ struct
+ {
+ float xn1, xn2, yn1, yn2;
+ } l, r;
+};
+
+static void wahwah_free(void *data)
+{
+ free(data);
+}
+
+static void wahwah_process(void *data, struct dspfilter_output *output,
+ const struct dspfilter_input *input)
+{
+ unsigned i;
+ struct wahwah_data *wah = (struct wahwah_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] };
+
+ if ((wah->skipcount++ % lfoskipsamples) == 0)
+ {
+ float frequency = (1.0 + cos(wah->skipcount * wah->lfoskip + wah->phase)) / 2.0;
+ frequency = frequency * wah->depth * (1.0 - wah->freqofs) + wah->freqofs;
+ frequency = exp((frequency - 1.0) * 6.0);
+
+ float omega = M_PI * frequency;
+ float sn = sin(omega);
+ float cs = cos(omega);
+ float alpha = sn / (2.0 * wah->res);
+
+ wah->b0 = (1.0 - cs) / 2.0;
+ wah->b1 = 1.0 - cs;
+ wah->b2 = (1.0 - cs) / 2.0;
+ wah->a0 = 1.0 + alpha;
+ wah->a1 = -2.0 * cs;
+ wah->a2 = 1.0 - alpha;
+ }
+
+ 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;
+ 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;
+
+ wah->l.xn2 = wah->l.xn1;
+ wah->l.xn1 = in[0];
+ wah->l.yn2 = wah->l.yn1;
+ wah->l.yn1 = out_l;
+
+ wah->r.xn2 = wah->r.xn1;
+ wah->r.xn1 = in[1];
+ wah->r.yn2 = wah->r.yn1;
+ wah->r.yn1 = out_r;
+
+ out[0] = out_l;
+ out[1] = out_r;
+ }
+}
+
+static void *wahwah_init(const struct dspfilter_info *info,
+ const struct dspfilter_config *config, void *userdata)
+{
+ struct wahwah_data *wah = (struct wahwah_data*)calloc(1, sizeof(*wah));
+ if (!wah)
+ return NULL;
+
+ config->get_float(userdata, "lfo_freq", &wah->freq, 1.5f);
+ config->get_float(userdata, "lfo_start_phase", &wah->startphase, 0.0f);
+ config->get_float(userdata, "freq_offset", &wah->freqofs, 0.3f);
+ config->get_float(userdata, "depth", &wah->depth, 0.7f);
+ config->get_float(userdata, "resonance", &wah->res, 2.5f);
+
+ wah->lfoskip = wah->freq * 2.0 * M_PI / info->input_rate;
+ wah->phase = wah->startphase * M_PI / 180.0;
+
+ return wah;
+}
+
+static const struct dspfilter_implementation wahwah_plug = {
+ wahwah_init,
+ wahwah_process,
+ wahwah_free,
+
+ DSPFILTER_API_VERSION,
+ "Wah-Wah",
+ "wahwah",
+};
+
+#ifdef HAVE_FILTERS_BUILTIN
+#define dspfilter_get_implementation wahwah_dspfilter_get_implementation
+#endif
+
+const struct dspfilter_implementation *dspfilter_get_implementation(dspfilter_simd_mask_t mask)
+{
+ (void)mask;
+ return &wahwah_plug;
+}
+
+#undef dspfilter_get_implementation
+