updates

lib/fm_modulator.c

@@ -0,0 +1,13 @@
+#include "fm_modulator.h"
+
+void init_fm_modulator(FMModulator *fm, float frequency, float deviation, float sample_rate) {
+    fm->frequency = frequency;
+    fm->deviation = deviation;
+    init_oscillator(&fm->osc, frequency, sample_rate);
+}
+
+float modulate_fm(FMModulator *fm, float sample) {
+    float inst_freq = fm->frequency+(sample*fm->deviation);
+    change_oscillator_frequency(&fm->osc, inst_freq);
+    return get_oscillator_sin_sample(&fm->osc);
+}

lib/fm_modulator.h

@@ -0,0 +1,11 @@
+#include "oscillator.h"
+
+typedef struct
+{
+    float frequency;
+    float deviation;
+    Oscillator osc;
+} FMModulator;
+
+void init_fm_modulator(FMModulator *fm, float frequency, float deviation, float sample_rate);
+float modulate_fm(FMModulator *fm, float sample);