Add FM synth

10 files changed, 189 insertions, 27 deletions

diff --git a/mmband/api/adsr.h b/mmband/api/adsr.h
index d9a9e1b..62b58d2 100644
--- a/mmband/api/adsr.h
+++ b/mmband/api/adsr.h
@@ -1,21 +1,23 @@
 #ifndef MMBAND_ADSR_H
 #define MMBAND_ADSR_H
 
+#include <mmband/api/lib.h>
+
 typedef struct adsr *adsr_ref;
 
-adsr_ref    adsr_new    ();
-void        adsr_free   (adsr_ref adsr);
+MMAPI adsr_ref  adsr_new    ();
+MMAPI void      adsr_free   (adsr_ref adsr);
 
-void        adsr_reset  (adsr_ref adsr);
-void        adsr_gate   (adsr_ref adsr);
-float       adsr_tick   (adsr_ref adsr);
+MMAPI void      adsr_reset  (adsr_ref adsr);
+MMAPI void      adsr_gate   (adsr_ref adsr);
+MMAPI float     adsr_tick   (adsr_ref adsr);
 
-void        adsr_set_attack     (adsr_ref adsr, float attack_rate);
-void        adsr_set_decay      (adsr_ref adsr, float decay_rate);
-void        adsr_set_sustain    (adsr_ref adsr, float sustain_level);
-void        adsr_set_release    (adsr_ref adsr, float release_rate);
+MMAPI void      adsr_set_attack     (adsr_ref adsr, float attack_rate);
+MMAPI void      adsr_set_decay      (adsr_ref adsr, float decay_rate);
+MMAPI void      adsr_set_sustain    (adsr_ref adsr, float sustain_level);
+MMAPI void      adsr_set_release    (adsr_ref adsr, float release_rate);
 
-void        adsr_set_asc_target     (adsr_ref adsr, float target);
-void        adsr_set_desc_target    (adsr_ref adsr, float target);
+MMAPI void      adsr_set_asc_target     (adsr_ref adsr, float target);
+MMAPI void      adsr_set_desc_target    (adsr_ref adsr, float target);
 
 #endif
diff --git a/mmband/api/filter.h b/mmband/api/filter.h
deleted file mode 100644
index e69de29..0000000
--- a/mmband/api/filter.h
+++ /dev/null
diff --git a/mmband/api/instrument.h b/mmband/api/instrument.h
index 3fd07da..bad0d48 100644
--- a/mmband/api/instrument.h
+++ b/mmband/api/instrument.h
@@ -1,17 +1,25 @@
 #ifndef MMBAND_INSTRUMENT_H
 #define MMBAND_INSTRUMENT_H
 
+#include <mmband/api/lib.h>
+
 enum filter_type {
-    FILTER_NONE = 0,
+    FILTER_NONE,
     FILTER_LOWPASS,
     FILTER_HIGHPASS,
-    FILTER_NOTCH,
     FILTER_LOWSHELF,
-    FILTER_HIGHSHELF
+    FILTER_HIGHSHELF,
+    FILTER_NOTCH
+};
+
+enum algorithm {
+    ALGORITHM_NONE,
+    ALGORITHM_RING,
+    ALGORITHM_FREQUENCY
 };
 
 enum osc_type {
-    OSC_NONE = 0,
+    OSC_NONE,
     OSC_SINE,
     OSC_SQUARE,
     OSC_TRIANGLE,
@@ -21,18 +29,19 @@ enum osc_type {
 // INSTRUMENT CREATION, TWEAKS
 typedef struct instrument *instrument_ref;
 
-instrument_ref      new_instrument      ();
-void                free_instrument     (instrument_ref instrument);
-// int              set_algorithm       (instrument_ref instrument, enum algorithm alg);
-int                 ins_set_osc         (instrument_ref instrument, enum osc_type osc);
-void                ins_set_sample_rate (instrument_ref instrument, int sample_rate);
+MMAPI instrument_ref    ins_new             ();
+MMAPI void              ins_free            (instrument_ref instrument);
+// int                  ins_set_algorithm   (instrument_ref instrument, enum algorithm alg);
+MMAPI void              ins_set_carrier     (instrument_ref instrument, enum osc_type osc);
+MMAPI void              ins_set_modulator   (instrument_ref instrument, enum osc_type osc);
+// void                 ins_set_filter      (instrument_ref instrument, enum filter_type filter);
 
-// OUTPUT CREATION, TWEAKS
-struct audio_out {
-    float left_phase;
-    float right_phase;
-};
+MMAPI void              ins_set_carrier_amplitude   (instrument_ref instrument, float amplitude);
+MMAPI void              ins_set_carrier_frequency   (instrument_ref instrument, float amplitude);
+MMAPI void              ins_set_modulator_amplitude (instrument_ref instrument, float amplitude);
+MMAPI void              ins_set_frequency_ratio     (instrument_ref instrument, float ratio);
+MMAPI void              ins_set_frequency           (instrument_ref instrument, float frequency);
 
-struct audio_out    instrument_tick     (instrument_ref instrument);
+MMAPI float             ins_tick            (instrument_ref instrument, int sample_rate);
 
 #endif
diff --git a/mmband/api/lib.h b/mmband/api/lib.h
new file mode 100644
index 0000000..5c1f2f8
--- /dev/null
+++ b/mmband/api/lib.h
@@ -0,0 +1,14 @@
+#ifndef MMBAND_LIB_EXPORTS_H
+#define MMBAND_LIB_EXPORTS_H
+
+#if defined _WIN32
+#if defined mmband_EXPORTS
+#define MMAPI __declspec(dllexport)
+#else
+#define MMAPI __declspec(dllimport)
+#endif
+#else
+#define MMAPI
+#endif
+
+#endif
diff --git a/mmband/instrument.c b/mmband/instrument.c
index 96a8952..38c7d43 100644
--- a/mmband/instrument.c
+++ b/mmband/instrument.c
@@ -1,4 +1,110 @@
+#include <math.h>
+#include <stdlib.h>
+
 #include <mmband/api/instrument.h>
 #include <mmband/api/adsr.h>
 
-struct instrument { };
+#include <mmband/waves/waveform.h>
+
+struct oscillation {
+    enum osc_type type; 
+
+    float frequency;
+    float phase;
+    float amplitude;
+};
+
+struct instrument {
+    struct oscillation carrier;
+    struct oscillation modulator;
+
+    float frequency_ratio;
+};
+
+float osc_tick (struct oscillation *osc, int sample_rate) {
+    float sample = 0.0;
+
+    switch (osc->type) {
+        case OSC_NONE:
+            sample = osc->amplitude * none(osc->phase);
+            break;
+        case OSC_SINE:
+            sample = osc->amplitude * sine(osc->phase);
+            break;
+        case OSC_SQUARE:
+            sample = osc->amplitude * square(osc->phase);
+            break;
+        case OSC_SAW:
+            sample = osc->amplitude * saw(osc->phase);
+            break;
+        case OSC_TRIANGLE:
+            sample = osc->amplitude * triangle(osc->phase);
+            break;
+    }
+
+    osc->phase = fmod(osc->phase + osc->frequency * 2.0 * M_PI / sample_rate, 2.0 * M_PI);
+    return sample;
+}
+
+// Currently default to ring modulation
+// TODO: add others
+float modulate (struct oscillation *carrier, struct oscillation *modulator, int sample_rate) {
+    return osc_tick(carrier, sample_rate) * osc_tick(modulator, sample_rate);
+}
+
+instrument_ref ins_new () {
+    instrument_ref instrument = malloc(sizeof(struct instrument));
+
+    instrument->frequency_ratio = 1.0;
+
+    instrument->carrier.type = OSC_SINE;
+    instrument->carrier.amplitude = 0.0;
+    instrument->carrier.frequency = 0.0;
+    instrument->carrier.phase = 0.0;
+
+    instrument->modulator.type = OSC_SINE;
+    instrument->carrier.amplitude = 0.0;
+    instrument->carrier.frequency = 0.0;
+    instrument->carrier.phase = 0.0;
+
+    return instrument;
+}
+
+void ins_free (instrument_ref instrument) {
+    free(instrument);
+}
+
+void ins_set_carrier (instrument_ref instrument, enum osc_type osc) {
+    instrument->carrier.type = osc;
+    instrument->carrier.amplitude = 0.0;
+    instrument->carrier.frequency = 0.0;
+    instrument->carrier.phase = 0.0;
+}
+
+void ins_set_modulator (instrument_ref instrument, enum osc_type osc) {
+    instrument->modulator.type = osc;
+    instrument->modulator.amplitude = 0.0;
+    instrument->modulator.frequency = 0.0;
+    instrument->modulator.phase = 0.0;
+}
+
+void ins_set_carrier_amplitude (instrument_ref instrument, float amplitude) {
+    instrument->carrier.amplitude = amplitude;
+}
+
+void ins_set_modulator_aplitude (instrument_ref instrument, float amplitude) {
+    instrument->modulator.amplitude = amplitude;
+}
+
+void ins_set_frequency_ratio (instrument_ref instrument, float frequency_ratio) {
+    instrument->frequency_ratio = frequency_ratio;
+}
+
+void ins_set_frequency (instrument_ref instrument, float frequency) {
+    instrument->carrier.frequency = frequency;
+    instrument->modulator.frequency = frequency * instrument->frequency_ratio;
+}
+
+float ins_tick (instrument_ref instrument, int sample_rate) {
+    return modulate(&instrument->carrier, &instrument->modulator, sample_rate);
+}
diff --git a/mmband/waves/none.c b/mmband/waves/none.c
index e69de29..110dc1c 100644
--- a/mmband/waves/none.c
+++ b/mmband/waves/none.c
@@ -0,0 +1,7 @@
+#include <mmband/waves/waveform.h>
+
+float zero (float phase) {
+    (void) phase;
+
+    return 0.0;
+}
diff --git a/mmband/waves/saw.c b/mmband/waves/saw.c
index e69de29..4ce7663 100644
--- a/mmband/waves/saw.c
+++ b/mmband/waves/saw.c
@@ -0,0 +1,6 @@
+#include <math.h>
+#include <mmband/waves/waveform.h>
+
+float saw (float phase) {
+    return -1.0 - (2.0 * fmod(phase / M_PI, 1.0));
+}
diff --git a/mmband/waves/sine.c b/mmband/waves/sine.c
index e69de29..52cf157 100644
--- a/mmband/waves/sine.c
+++ b/mmband/waves/sine.c
@@ -0,0 +1,6 @@
+#include <math.h>
+#include <mmband/waves/waveform.h>
+
+float sine (float phase) {
+    return sinf(phase);
+}
diff --git a/mmband/waves/square.c b/mmband/waves/square.c
index e69de29..97ad5e9 100644
--- a/mmband/waves/square.c
+++ b/mmband/waves/square.c
@@ -0,0 +1,6 @@
+#include <math.h>
+#include <mmband/waves/waveform.h>
+
+float square (float phase) {
+    return (phase <= M_PI) ? 1.0 : -1.0;
+}
diff --git a/mmband/waves/triangle.c b/mmband/waves/triangle.c
index e69de29..bf805ed 100644
--- a/mmband/waves/triangle.c
+++ b/mmband/waves/triangle.c
@@ -0,0 +1,6 @@
+#include <math.h>
+#include <mmband/waves/waveform.h>
+
+float triangle (float phase) {
+    return (acosf(sinf(phase))) / M_PI;
+}