1 files changed, 17 insertions, 13 deletions
diff --git a/Core/Src/Effects/ringmod.c b/Core/Src/Effects/ringmod.c
index 732f68e..1b411dc 100755
--- a/Core/Src/Effects/ringmod.c
+++ b/Core/Src/Effects/ringmod.c
@@ -8,30 +8,34 @@
 #include "cs4272.h"
 #include "ringmod.h"
 #include <math.h>
+#include <float.h>
 
-/* ring modulator */
-void ringmod(float *samples, size_t range_min, size_t range_max) {
+/* MF-102S ring modulator */
+void ringmod(float *samples, const size_t range_min, const size_t range_max, const struct RingModParams *params) {
     static float lfo_phase = 0.0f;
     static float carrier_phase = 0.0f;
 
-    const float frequency = 156.0f;
-    const float amount = 0.67f;
     const float sample_rate = (float)SAMPLE_RATE;
+    const float inverse_sample_rate = 1.0f / sample_rate;
 
-    float lfo_increment = M_TWOPI * (0.18f / sample_rate);
-
-    /* plus two because of */
+    /* samples are interleaved */
     for (size_t i = range_min; i < range_max; i += 2) {
-        lfo_phase = fmodf(lfo_phase + lfo_increment, M_TWOPI);
+        float frequency_lfo = 0.0f;
 
-        float lfo = sinf(lfo_phase);
+        if (params->square_lfo) {
+            frequency_lfo = (lfo_phase < 0.5f) ? params->lfo_amount : -params->lfo_amount;
+        } else {
+            frequency_lfo = params->lfo_amount * sinf(M_TWOPI * lfo_phase);
+        }
 
-        float carrier_increment = M_TWOPI * ((frequency + lfo * (frequency * 3.0f * amount)) / sample_rate);
+        float carrier = sinf(M_TWOPI * carrier_phase);
 
-        carrier_phase = fmodf(carrier_phase + carrier_increment, M_TWOPI);
+        samples[i] = (samples[i] * (1.0f - params->mix)) + (samples[i] * carrier * params->mix);
 
-        float carrier = sinf(carrier_phase);
+        lfo_phase += params->lfo_rate * inverse_sample_rate;
+        lfo_phase = fmod(lfo_phase, 1.0f);
 
-        samples[i] = (samples[i] * 0.50f) + (samples[i] * carrier * 0.50f);
+        carrier_phase += (params->frequency + frequency_lfo) * inverse_sample_rate;
+        carrier_phase = fmod(carrier_phase, 1.0f);
     }
 }