From 1eeba03da0222a117054eca53e7be8ee1e8bd970 Mon Sep 17 00:00:00 2001
From: Mitja Felicijan <mitja.felicijan@gmail.com>
Date: Mon, 7 Oct 2024 17:41:54 +0200
Subject: Added ALSA MIDI example

---
 .gitignore |  1 +
 Makefile   |  5 ++++-
 README.md  | 12 ++++++++++++
 example3.c | 14 +++++++-------
 example4.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 78 insertions(+), 8 deletions(-)
 create mode 100644 example4.c

diff --git a/.gitignore b/.gitignore
index c21c3a6..47fd165 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 example1
 example2
 example3
+example4
 
diff --git a/Makefile b/Makefile
index 51e4b2d..727e920 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,11 @@ tests: build-portmidi
 	$(CC) -Wall example2.c minisdl_audio.c -lm -ldl -lpthread -o example2
 	$(CC) -Wall example3.c -L./portmidi -lportmidi -o example3
 
-run-example3:
+run-example3: tests
 	LD_LIBRARY_PATH=./portmidi ./example3
 
+run-example4:
+	$(CC) example4.c -lasound -lm -o example4 && ./example4
+
 build-portmidi:
 	cd portmidi && cmake . && make
diff --git a/README.md b/README.md
index 379eb42..442c27e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,17 @@
 # Tiny terminal DAW
 
+`ttdaw` is a tiny terminal based digital audio workstation made for fun and
+experimentation and learning more about audio and MIDI in general.
+
+## Documentations
+
+- https://developer.apple.com/documentation/coremidi
+- https://www.alsa-project.org/alsa-doc/alsa-lib/seq.html
+
+## Reading material
+
+- https://www.izotope.com/en/learn/fundamental-frequency-harmonics.html
+
 ## Soundfonts
 
 - https://dev.nando.audio/pages/soundfonts.html
diff --git a/example3.c b/example3.c
index 9dea995..a2103f2 100644
--- a/example3.c
+++ b/example3.c
@@ -20,12 +20,12 @@ int main() {
 	}
 
 	/* // Open a MIDI input device */
-	/* stream = Pm_OpenInput(&err, NULL, NULL, NUM_INPUTS, NULL, 0); */
-	/* if (err != pmNoError) { */
-	/*     fprintf(stderr, "Error opening MIDI input device: %s\n", Pm_GetErrorText(err)); */
-	/*     Pm_Terminate(); */
-	/*     exit(1); */
-	/* } */
+	stream = (PortMidiStream *)Pm_OpenInput(&err, NULL, NULL, NUM_INPUTS, NULL, 0);
+	if (err != pmNoError) {
+	    fprintf(stderr, "Error opening MIDI input device: %s\n", Pm_GetErrorText(err));
+	    Pm_Terminate();
+	    exit(1);
+	}
 
 	/* // Read MIDI messages from the input device */
 	/* while (1) { */
@@ -43,7 +43,7 @@ int main() {
 	/* } */
 
 	/* // Close the MIDI input device */
-	/* Pm_Close(stream); */
+	Pm_Close(stream);
 
 	// Terminate PortMIDI
 	Pm_Terminate();
diff --git a/example4.c b/example4.c
new file mode 100644
index 0000000..c14e5bc
--- /dev/null
+++ b/example4.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <alsa/asoundlib.h>
+
+#define CLIENT_NAME "ttdaw"
+#define MAX_MIDI_PORTS 4
+
+static snd_seq_t *seq_handle;
+static snd_seq_addr_t *ports;
+static int rate = 44100;
+
+int main(void) {
+	fprintf(stdout, "Example: Reading MIDI input\n");
+
+	snd_seq_t *seq_handle;
+
+	if (snd_seq_open(&seq_handle, "default", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
+		fprintf(stderr, "Error opening ALSA sequencer.\n");
+		exit(1);
+	}
+
+	if (snd_seq_set_client_name(seq_handle, CLIENT_NAME) < 0) {
+		fprintf(stderr, "Could not set up client name.\n");
+		exit(1);
+	}
+
+	if (snd_seq_create_simple_port(seq_handle, CLIENT_NAME,
+				SND_SEQ_PORT_CAP_WRITE |
+				SND_SEQ_PORT_CAP_SUBS_WRITE,
+				SND_SEQ_PORT_TYPE_MIDI_GENERIC |
+				SND_SEQ_PORT_TYPE_APPLICATION) < 0) {
+		fprintf(stderr, "Error creating sequencer port.\n");
+		exit(1);
+	}
+
+	char *port_name = "28:0";
+	if (snd_seq_parse_address(seq_handle, &ports[0], port_name) < 0) {
+		fprintf(stderr, "Invalid port %s.\n", port_name);
+		exit(1);
+	}
+
+	// Connecting ports.
+	for (int i = 0; i < MAX_MIDI_PORTS; ++i) {
+		int err = snd_seq_connect_from(seq_handle, 0, ports[i].client, ports[i].port);
+		if (err < 0) {
+			fprintf(stderr, "Cannot connect from port %d:%d - %s", ports[i].client, ports[i].port, snd_strerror(err));
+			exit(1);
+		}
+	}
+
+	snd_seq_close(seq_handle);
+	return 0;
+}
+
-- 
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