From cdd8f26a12b119219b256f5c8ae4d7f0ab88c985 Mon Sep 17 00:00:00 2001
From: Mitya Selivanov <automainint@guattari.tech>
Date: Wed, 14 Feb 2024 17:55:08 +0100
Subject: Improve playback code

---
 source/saw/main.c | 47 ++++++++++++++++++++++-------------------------
 1 file changed, 22 insertions(+), 25 deletions(-)

(limited to 'source')

diff --git a/source/saw/main.c b/source/saw/main.c
index 7bcc6d7..12b271e 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -60,7 +60,7 @@ enum {
 #ifdef __EMSCRIPTEN__
   BUFFER_SIZE = 1024 * 16,
 #else
-  BUFFER_SIZE  = 1024 * 2,
+  BUFFER_SIZE  = 1024 * 8,
 #endif
 
 #ifdef __EMSCRIPTEN__
@@ -348,8 +348,14 @@ static void saw_audio_render(void) {
   //  FIXME
   //  Improve performance.
 
-  i64 frame_count = (BUFFER_SIZE / CHANNEL_COUNT) -
-                    saw_playback_lookahead;
+  i64 frame_count = (BUFFER_SIZE / CHANNEL_COUNT);
+
+  if (mtx_lock(&saw_playback_mutex) != thrd_success) {
+    assert(0);
+    return;
+  }
+  frame_count -= saw_playback_lookahead;
+  mtx_unlock(&saw_playback_mutex);
 
   if (frame_count > 0) {
     memset(saw_playback_temp, 0,
@@ -362,26 +368,18 @@ static void saw_audio_render(void) {
 
         for (i32 k = 0; k < ROLL_COUNT; k++) {
           saw_roll_t *roll = saw_rolls + k;
-          if (!roll->enabled ||
-              saw_playback_frame + 1 <= roll->time ||
-              saw_playback_frame + 1 > roll->time + roll->duration)
+
+          if (!roll->enabled || saw_playback_frame < roll->time ||
+              saw_playback_frame > roll->time + roll->duration)
             continue;
 
-          i64 play_frame = roll->loop_duration == 0
-                               ? saw_playback_frame
-                               : saw_playback_frame -
-                                     ((saw_playback_frame + 1 -
-                                       roll->time) /
-                                      roll->loop_duration) *
-                                         roll->loop_duration;
+          i64 roll_frame = saw_playback_frame - roll->time;
+          if (roll->loop_duration != 0)
+            roll_frame = roll_frame % roll->loop_duration;
 
           for (i32 i = 0; i < SHEET_SIZE; i++) {
             saw_roll_note_t *note = roll->notes + i;
-            if (!note->enabled)
-              continue;
-            i64 note_frame = roll->time + note->time;
-            if (play_frame + 1 <= note_frame ||
-                play_frame > note_frame)
+            if (!note->enabled || note->time != roll_frame)
               continue;
 
             saw_play_voice(saw_tracks + roll->track, roll,
@@ -467,14 +465,13 @@ static void saw_audio_render(void) {
   }
 
 #ifndef __EMSCRIPTEN__
-  if (frame_count == 0 && !saw_playback_on) {
+  if (frame_count == 0 && !saw_playback_on)
     //  Sleep for 1/5 of the buffer duration
     thrd_sleep(
         &(struct timespec) {
             .tv_nsec = (200000000ll * BUFFER_SIZE / CHANNEL_COUNT) /
                        SAMPLE_RATE },
         NULL);
-  }
 #endif
 }
 
@@ -1299,14 +1296,14 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   //  Loop control
   //
   {
-    i64 x = x0 + pianokey_width + sheet_offset;
-    i64 y = frame_height - y0 - height + text_height;
-    i64 w = width - pianokey_width - sheet_offset;
-    i64 h = header_height / 5;
+    i64 x      = x0 + pianokey_width + sheet_offset;
+    i64 y      = frame_height - y0 - height + text_height;
+    i64 w      = width - pianokey_width - sheet_offset;
+    i64 h      = header_height / 5;
+    i64 border = 5;
 
     char repeat[] = "\uf363";
 
-    i64 border = 5;
     nvgFontSize(saw_nvg, header_height - border * 2);
     nvgFontFaceId(saw_nvg, saw_font_icons);
     if (roll->loop_duration == 0)
-- 
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