Noise for haptics (#31)

conf/monocoque.config

@@ -26,6 +26,7 @@ configs = (
             modulation   = "frequency";
             frequency    = 17;
             frequencyMax = 37;
+            noise        = 10; // additive noise in Hz
         },
         {
             device       = "Sound";

src/monocoque/devices/sound/usb_generic_shaker_pulse.c

@@ -16,6 +16,15 @@
 #define M_PI  (3.14159265)
 #endif
 
+static double apply_noise(double base_freq, double noise_amount) {
+    if (noise_amount > 0.0) {
+        double r = (double) rand() / RAND_MAX * 2.0 - 1.0;
+        return base_freq + r * noise_amount;
+    } else {
+        return base_freq;
+    }
+}
+
 void gear_sound_stream(pa_stream *s, size_t length, void *userdata) {
 
     SoundData* data = (SoundData*)userdata;
@@ -24,21 +33,44 @@ void gear_sound_stream(pa_stream *s, size_t length, void *userdata) {
 
 
     for (size_t i = 0; i < num_samples; i++) {
-        static double t = 0.0;
-        double sample = 0;
-        if (data->frequency>0)
-        {
-            sample = ((double)data->curr_amplitude/100) * 32767.0 * sin(2.0 * M_PI * data->curr_frequency * data->curr_duration);
-        }
 
+        double sample = 0;
+
+        if (data->curr_frequency>0.0)
+        {
+            double t = data->phase;
+            double a = (double)data->curr_amplitude/100;
+
+            // fade-out 5ms to prevent discontinuity
+            static double fade_out_duration = 0.005;
+
+            double remaining = data->duration - data->curr_duration;
+            if (remaining < fade_out_duration) {
+                a *= remaining / fade_out_duration;
+            }
+
+            sample = a * 32767.0 * sin(2.0 * M_PI * t);
+
+            double f = apply_noise(data->curr_frequency, data->noise);
+
+            t += f / SAMPLE_RATE;
+            if (t >= 1.0) {
+                t -= floor(t);
+            }
+
+            data->phase = t;
+
+            data->curr_duration += 1.0 / SAMPLE_RATE;
+            if (data->curr_duration >= data->duration) {
+                data->curr_duration = 0.0;
+                data->curr_frequency = 0.0;
+                data->phase = 0.0;
+            }
+
+        }
 
         buffer[i] = (int16_t)sample;
 
-        data->curr_duration += 1.0 / SAMPLE_RATE;
-        if (data->curr_duration >= data->duration) {
-            data->curr_duration = 0.0;
-            data->curr_frequency = 0.0;
-        }
     }
     pa_stream_write(s, buffer, length, NULL, 0LL, PA_SEEK_RELATIVE);
 }
@@ -46,7 +78,6 @@ void gear_sound_stream(pa_stream *s, size_t length, void *userdata) {
 void engine_sound_stream(pa_stream *s, size_t length, void *userdata) {
 
     SoundData* data = (SoundData*)userdata;
-    double freq = data->curr_frequency;
 
     size_t num_samples = length / sizeof(int16_t);
 
@@ -62,7 +93,9 @@ void engine_sound_stream(pa_stream *s, size_t length, void *userdata) {
 
         buffer[i] = (int16_t)sample;
 
-        t += freq / SAMPLE_RATE;
+        double f = apply_noise(data->curr_frequency, data->noise);
+
+        t += f / SAMPLE_RATE;
         if (t >= 1.0) {
             t -= floor(t);
         }

src/monocoque/devices/sounddevice.c

@@ -177,6 +177,7 @@ int sounddev_init(SoundDevice* sounddevice, const char* devname, MonocoqueTyreId
     slogi("pan is: %i", sds.pan);
     slogi("channels is: %i", sds.channels);
     slogi("duration is: %f", sds.duration);
+    slogi("noise is: %i", sds.noise);
 
 
     sounddevice->modulationType = sds.modulation;
@@ -184,6 +185,7 @@ int sounddev_init(SoundDevice* sounddevice, const char* devname, MonocoqueTyreId
     sounddevice->sounddata.frequencyMax = sds.frequencyMax;
     sounddevice->sounddata.amplitude = sds.amplitude;
     sounddevice->sounddata.amplitudeMax = sds.amplitudeMax;
+    sounddevice->sounddata.noise = (double)sds.noise;
     sounddevice->sounddata.curr_duration = 0;
 
     sounddevice->sounddata.phase = 0;

src/monocoque/devices/sounddevice.h

@@ -30,6 +30,7 @@ typedef struct
     uint32_t curr_amplitude;
     double curr_duration;
     double phase;
+    double noise;
 }
 SoundData;
 

src/monocoque/helper/confighelper.c

@@ -747,6 +747,7 @@ int devsetup(const char* device_type, const char* device_subtype, const char* co
             ds->sounddevsettings.pan = 0;
             ds->sounddevsettings.channels = 1;
             ds->sounddevsettings.duration = 2.0;
+            ds->sounddevsettings.noise = 0;
             if (ds->effect_type == EFFECT_GEARSHIFT)
             {
                 ds->sounddevsettings.duration = .125;
@@ -762,6 +763,7 @@ int devsetup(const char* device_type, const char* device_subtype, const char* co
                 config_setting_lookup_int(device_settings, "pan", &ds->sounddevsettings.pan);
                 config_setting_lookup_int(device_settings, "channels", &ds->sounddevsettings.channels);
                 config_setting_lookup_float(device_settings, "duration", &ds->sounddevsettings.duration);
+                config_setting_lookup_int(device_settings, "noise", &ds->sounddevsettings.noise);
 
                 const char* temp = NULL;
                 int found = 0;

src/monocoque/helper/confighelper.h

@@ -185,6 +185,7 @@ typedef struct
     double duration;
     char* dev;
     SoundEffectModulationType modulation;
+    int noise;
 }
 SoundDeviceSettings;