Added mutex and proper audio playback

9 files changed, 96 insertions, 11 deletions

diff --git a/Makefile b/Makefile
index 8681948..fca5cb9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CC      := cc
 CFLAGS  := -Wall -Wextra -Wshadow -Wunused -Wswitch-enum -Wpedantic -ggdb
 LDFLAGS := -lm -ldl -lpthread -lasound
-FILES   := main.c midi.c synth.c minisdl_audio.c
+FILES   := main.c midi.c synth.c mutex.c minisdl_audio.c
 PROG    := ttdaw
 
 $(PROG): main.c
diff --git a/main.c b/main.c
index 5a1916e..4eb4cf7 100644
--- a/main.c
+++ b/main.c
@@ -7,6 +7,7 @@
 #include "version.h"
 #include "midi.h"
 #include "synth.h"
+#include "mutex.h"
 
 void help(const char *argv0) {
 	printf("Usage: %s [options]\n"
@@ -70,6 +71,9 @@ int main(int argc, char *argv[]) {
 	fprintf(stdout, "> Device port:   %s\n", port_name);
 	fprintf(stdout, "> Soundfont:     %s\n", soundfont_file);
 
+	// Create mutex.
+	initialize_mutex();	
+
 	// Create synth thread.
 	pthread_t synth_thread;
 	SynthArgs synth_args = { soundfont_file };
@@ -91,6 +95,9 @@ int main(int argc, char *argv[]) {
 	pthread_join(midi_thread, NULL);
 	pthread_join(synth_thread, NULL);
 
+	// Destroy mutex.
+	destroy_mutex();
+
 	fprintf(stdout, "Exiting...\n");
 	return 0;
 }
diff --git a/midi.c b/midi.c
index 3d21f79..f389826 100644
--- a/midi.c
+++ b/midi.c
@@ -5,6 +5,7 @@
 #include <alsa/asoundlib.h>
 
 #include "midi.h"
+#include "mutex.h"
 
 static snd_seq_t *seq_handle;
 static snd_seq_addr_t *ports;
@@ -81,8 +82,12 @@ void *midi(void *arg) {
 				}
 
 				if (ev) {
+					pthread_mutex_lock(&mutex);
 					switch (ev->type) {
 						case SND_SEQ_EVENT_NOTEON:
+							shared_data.note = ev->data.note.note;
+							shared_data.state = 1;
+							shared_data.velocity = ev->data.note.velocity;
 							printf("%3d:%-3dNote on  %2d, note %d, velocity: %3d\n",
 									ev->source.client, ev->source.port,
 									ev->data.note.channel,
@@ -91,14 +96,23 @@ void *midi(void *arg) {
 							break;
 
 						case SND_SEQ_EVENT_NOTEOFF:
+							shared_data.note = ev->data.note.note;
+							shared_data.state = 0;
+							shared_data.velocity = 0;
 							printf("%3d:%-3dNote off\t%2d, note %d\n",
 									ev->source.client, ev->source.port,
 									ev->data.note.channel,
 									ev->data.note.note);
 							break;
+						default:
+							break;
+					}
 
+					shared_data.action = 1;
+					shared_data.preset = 3;
 
-					}
+					pthread_cond_signal(&cond_synth);
+					pthread_mutex_unlock(&mutex);
 				}
 			}
 
diff --git a/midi.h b/midi.h
index 81b105b..ddbaef8 100644
--- a/midi.h
+++ b/midi.h
@@ -1,8 +1,8 @@
-#include <alsa/asoundlib.h>
-
 #ifndef MIDI_H_
 #define MIDI_H_
 
+#include <alsa/asoundlib.h>
+
 #define CLIENT_NAME "ttdaw"
 #define MAX_MIDI_PORTS 1
 
diff --git a/mutex.c b/mutex.c
new file mode 100644
index 0000000..007928d
--- /dev/null
+++ b/mutex.c
@@ -0,0 +1,19 @@
+#include <pthread.h>
+#include "mutex.h"
+
+SharedData shared_data;
+
+pthread_mutex_t mutex;
+pthread_cond_t cond_midi;
+pthread_cond_t cond_synth;
+
+void initialize_mutex() {
+	pthread_mutex_init(&mutex, NULL);
+	pthread_cond_init(&cond_synth, NULL);
+}
+
+void destroy_mutex() {
+	pthread_mutex_destroy(&mutex);
+	pthread_cond_destroy(&cond_synth);
+}
+
diff --git a/mutex.h b/mutex.h
new file mode 100644
index 0000000..2f3c653
--- /dev/null
+++ b/mutex.h
@@ -0,0 +1,24 @@
+#ifndef MUTEX_H
+#define MUTEX_H
+
+#include <pthread.h>
+
+typedef struct {
+	int note;
+	int state;
+	int velocity;
+	int preset;
+	int action;
+} SharedData;
+
+extern SharedData shared_data;
+
+extern pthread_mutex_t mutex;
+extern pthread_cond_t cond_midi;
+extern pthread_cond_t cond_synth;
+
+void initialize_mutex();
+void destroy_mutex();
+
+#endif // MUTEX_H
+
diff --git a/soundfonts/general-808.sf2 b/soundfonts/general-808.sf2
new file mode 100644
index 0000000..3e128d8
--- /dev/null
+++ b/soundfonts/general-808.sf2
diff --git a/synth.c b/synth.c
index d391056..05c3664 100644
--- a/synth.c
+++ b/synth.c
@@ -2,6 +2,7 @@
 #include <unistd.h>
 
 #include "synth.h"
+#include "mutex.h"
 #include "minisdl_audio.h"
 
 #define TSF_IMPLEMENTATION
@@ -12,7 +13,7 @@ static SDL_mutex* g_Mutex;
 
 // Render the audio samples in float format.
 static void AudioCallback(void* data, Uint8 *stream, int len) {
-	int SampleCount = (len / (2 * sizeof(float))); // 2 output channels.
+	int SampleCount = (len / (AUDIO_CHANNELS * sizeof(float))); // 2 output channels.
 	SDL_LockMutex(g_Mutex); // Get exclusive lock.
 	tsf_render_float(g_TinySoundFont, (float*)stream, SampleCount, 0);
 	SDL_UnlockMutex(g_Mutex);
@@ -22,10 +23,10 @@ void *synth(void *arg) {
 	SynthArgs* args = (SynthArgs*)arg;
 
 	SDL_AudioSpec OutputAudioSpec;
-	OutputAudioSpec.freq = 44100;
+	OutputAudioSpec.freq = AUDIO_FREQ;
 	OutputAudioSpec.format = AUDIO_F32;
-	OutputAudioSpec.channels = 2;
-	OutputAudioSpec.samples = 4096;
+	OutputAudioSpec.channels = AUDIO_CHANNELS;
+	OutputAudioSpec.samples = AUDIO_SAMPLES;
 	OutputAudioSpec.callback = AudioCallback;
 
 	// Initialize the audio system.
@@ -56,12 +57,28 @@ void *synth(void *arg) {
 	SDL_PauseAudio(0);
 
 	while (1) {
-		sleep(1);
+		pthread_mutex_lock(&mutex);
+		while (shared_data.action == 0) {
+			pthread_cond_wait(&cond_synth, &mutex);
+		}
 
 		SDL_LockMutex(g_Mutex);
-		tsf_note_off(g_TinySoundFont, 1, 50);
-		tsf_note_on(g_TinySoundFont, 1, 50, 1.0f);
+
+		if (shared_data.state == 0) {
+			tsf_note_off(g_TinySoundFont, shared_data.preset, shared_data.note);
+		} else {
+			float normalized_velocity = (float)shared_data.velocity / 127.0f;
+			tsf_note_on(g_TinySoundFont, shared_data.preset, shared_data.note, normalized_velocity);
+		}
+
 		SDL_UnlockMutex(g_Mutex);
+
+		printf("Consumed: note=%d, state=%d velocity:%d\n", shared_data.note, shared_data.state, shared_data.velocity);
+
+		// Reset state to indicate data has been consumed.
+		shared_data.action = 0; 
+
+		pthread_mutex_unlock(&mutex);
 	}
 }
 
diff --git a/synth.h b/synth.h
index 1976745..90fd410 100644
--- a/synth.h
+++ b/synth.h
@@ -1,6 +1,10 @@
 #ifndef SYNTH_H_
 #define SYNTH_H_
 
+#define AUDIO_FREQ 44100
+#define AUDIO_SAMPLES 64
+#define AUDIO_CHANNELS 2
+
 typedef struct {
 	char *soundfont_file;
 } SynthArgs;