From 2875bd24390d48d2af44071869757b6f1ba35498 Mon Sep 17 00:00:00 2001
From: grm <grm@eyesin.space>
Date: Sun, 19 Oct 2025 12:45:07 +0300
Subject: Initial sequencer

---
 src/sequencer.c | 171 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 src/sequencer.c

(limited to 'src')

diff --git a/src/sequencer.c b/src/sequencer.c
new file mode 100644
index 0000000..5687640
--- /dev/null
+++ b/src/sequencer.c
@@ -0,0 +1,171 @@
+#include <stdlib.h>
+#include <portmidi.h>
+#include <porttime.h>
+#include <stdio.h>
+#include <string.h>
+#include <raylib.h>
+#include <pthread.h>
+#include <math.h>
+
+#include "synth_common.h"
+
+#define MIDI_NOTE_ON  0x90
+#define MIDI_NOTE_OFF 0x80
+#define MIDI_CHANNEL  0
+#define SLEEP_INTERVAL_MS 2.0   // main loop sleep
+
+
+
+//-------------------------------------------------
+// Helper for time math
+//-------------------------------------------------
+
+typedef struct step_t {
+  PmTimestamp note_on;
+  PmTimestamp note_off;
+  float duration;
+  int note; 
+} step_t;
+
+typedef struct pattert_t {
+  step_t *steps;
+  uint n; // total
+  uint c; // current
+} pattern_t;
+
+typedef struct sequencer_t {
+  PortMidiStream *stream;
+  int exitted;
+
+  float bpm;
+  int steps;
+  pattern_t *pattern;
+} sequencer_t;
+
+sequencer_t *
+init_sequencer() {
+  sequencer_t *seq = (sequencer_t *)malloc(sizeof(sequencer_t));
+
+  seq->exitted = 0;
+  seq->bpm = 100.0f;
+  seq->steps = 16;
+
+  seq->pattern = (pattern_t *)malloc(sizeof(pattern_t));
+  seq->pattern->steps = (step_t *)malloc(16 * sizeof(step_t));
+  seq->pattern->n = 16;
+  seq->pattern->c = 0;
+
+  for (uint i = 0; i < seq->pattern->n; i++) {
+    step_t *step = &seq->pattern->steps[i];
+    step->note = 40 + i;
+  }
+  
+  seq->stream = NULL;
+  PmError err = Pm_Initialize();
+  if (err != pmNoError) {
+    fprintf(stdout, "Pm Error: %s\n", Pm_GetErrorText(err));
+  }
+
+  const PmDeviceInfo *info;
+  int i;
+  for (i = 0; i < Pm_CountDevices(); i++) {
+    info = Pm_GetDeviceInfo(i);
+    if (!info->output) {
+      continue;
+    }
+    printf("%d: %s [input: %d output: %d opened: %d is_virt:%d] (interface: %s)\n", i, info->name, info->input, info->output, info->opened, info->is_virtual, info->interf);
+    if (0 == strcmp("Midi Through Port-0", info->name))
+      break;
+  }
+
+  printf("Selected device: %s [input: %d output: %d opened: %d is_virt:%d] (interf: %s)\n", info->name, info->input, info->output, info->opened, info->is_virtual, info->interf);
+
+  //no start for output Pt_Start(1, midiCallback, m);
+  err = Pm_OpenOutput(&(seq->stream), i, NULL, 512, NULL, NULL, 0);
+
+  if (err != pmNoError) {
+    fprintf(stdout, "Pm Error: %s\n", Pm_GetErrorText(err));
+  }
+
+  return seq;
+}
+
+void
+free_sequencer(sequencer_t * seq) {
+  Pm_WriteShort(seq->stream, 0, Pm_Message(0xFC /* MIDI_STOP */, 0, 0));
+  
+  Pm_Close(seq->stream);
+  Pm_Terminate();
+
+  free(seq);
+}
+
+static inline double ms_per_beat(sequencer_t * seq) {
+    return 60000.0 / seq->bpm;
+}
+static inline double ms_per_step(sequencer_t * seq) {
+    return ms_per_beat(seq) / seq->steps;
+}
+
+void
+rayrun(sequencer_t * seq) {
+  (void)seq;
+  SetTraceLogLevel(LOG_ERROR);
+  InitWindow(WIDTH, HEIGHT, "Raylib sequencer");
+  SetTargetFPS(60);
+  while (!WindowShouldClose()) {
+    // Draw
+    //----------------------------------------------------------------------------------
+    BeginDrawing();
+    ClearBackground(BLACK);
+
+
+    EndDrawing();
+    //----------------------------------------------------------------------------------
+  }
+  seq->exitted = 1;
+  CloseWindow();
+}
+
+void *
+sequencer_thread(void *arg)
+{
+  sequencer_t *seq = (sequencer_t *)arg;
+
+  while (!seq->exitted) {
+    //PmTimestamp current_time = Pt_Time();
+
+    step_t *step = &seq->pattern->steps[seq->pattern->c++];
+    if (seq->pattern->c >= seq->pattern->n) seq->pattern->c = 0;
+    
+    Pm_WriteShort(seq->stream, 0, Pm_Message(MIDI_NOTE_ON | MIDI_CHANNEL, step->note, 100));
+
+    Pt_Sleep(ms_per_step(seq)*4);
+    Pm_WriteShort(seq->stream, 0, Pm_Message(MIDI_NOTE_OFF | MIDI_CHANNEL, step->note, 0));
+
+    //Pt_Sleep(SLEEP_INTERVAL_MS);
+  }
+
+  printf("[Sequencer] Stopping.\n");
+  return NULL;
+}
+
+
+int
+main(void) {
+  sequencer_t * seq = init_sequencer();
+
+  pthread_t seq_thread;
+
+  // start sequencer thread
+  pthread_create(&seq_thread, NULL, sequencer_thread, seq);
+
+  // start gui
+  rayrun(seq);
+
+  pthread_join(seq_thread, NULL);
+
+  free_sequencer(seq);
+
+  return 0;
+}
-- 
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