Track looping

2 files changed, 92 insertions, 25 deletions

diff --git a/TODO b/TODO
index 45c00b7..d739785 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,6 @@
 To-Do list
 
 - Grid size changing
-- Track looping
 - UI: Playback controls
 - UI: Effects stack
 - UI: Volume control
@@ -52,3 +51,4 @@ Done
 - UI: Track composing
 - UI: Instrument settings
 - State load and store
+- Track looping
diff --git a/source/saw/main.c b/source/saw/main.c
index 43c9f3f..2a62e80 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -87,6 +87,7 @@ typedef struct {
   saw_roll_note_t notes[SHEET_SIZE];
   i64             time;
   i64             duration;
+  i64             loop_duration;
   i64             offset_x;
   i64             offset_y;
 
@@ -98,6 +99,7 @@ typedef struct {
   i32 grid_time;
   i8  offset_x_input;
   i8  offset_y_input;
+  i8  loop_input;
 } saw_roll_t;
 
 typedef struct {
@@ -247,13 +249,21 @@ static void saw_playback(i32 frame_count) {
         saw_playback_frame >= roll->time + roll->duration)
       continue;
 
+    i64 play_frame = roll->loop_duration == 0
+                         ? saw_playback_frame
+                         : saw_playback_frame -
+                               ((saw_playback_frame + frame_count -
+                                 roll->time) /
+                                roll->loop_duration) *
+                                   roll->loop_duration;
+
     for (i32 i = 0; i < SHEET_SIZE; i++) {
       saw_roll_note_t *note = roll->notes + i;
       if (!note->enabled)
         continue;
-      i64 frame = roll->time + note->time;
-      if (saw_playback_frame + frame_count <= frame ||
-          saw_playback_frame > frame)
+      i64 note_frame = roll->time + note->time;
+      if (play_frame + frame_count <= note_frame ||
+          play_frame > note_frame)
         continue;
 
       saw_play_voice(saw_tracks + roll->track, roll, note->pitch,
@@ -510,6 +520,7 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
           .notes            = { 0 },
           .time             = frame,
           .duration         = (6 * SAW_SAMPLE_RATE) / grid_rate,
+          .loop_duration    = 0,
           .offset_x         = 0,
           .offset_y         = ROLL_DEFAULT_OFFSET_Y,
 
@@ -519,6 +530,7 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
           .grid_time      = 0,
           .offset_x_input = 0,
           .offset_y_input = 0,
+          .loop_input     = 0,
         };
 
         saw_current_roll  = n;
@@ -527,7 +539,7 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
     }
   }
 
-  //  Offset input
+  //  Panning input
   //
 
   if (saw_mbutton_click) {
@@ -878,12 +890,13 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   i32 frame_height = sapp_height();
 
   i32 text_height     = 35;
+  i32 header_height   = 35;
   i32 pianokey_height = 35;
   i32 pianokey_width  = 100;
   i32 border          = 2;
 
   i32 sheet_offset = 40;
-  i32 sheet_scale  = (20 * SAW_SAMPLE_RATE) / (10000 * roll->rate);
+  i32 sheet_scale  = (40 * SAW_SAMPLE_RATE) / (10000 * roll->rate);
 
   //  Title text
   //
@@ -903,6 +916,40 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
           title.values, title.values + title.size);
   nvgFill(saw_nvg);
 
+  //  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;
+
+    nvgBeginPath(saw_nvg);
+    nvgRect(saw_nvg, x, y, w, h);
+    nvgRect(saw_nvg, x, y + h * 4, w, h);
+    nvgFillColor(saw_nvg, nvgRGBA(80, 60, 50, 160));
+    nvgFill(saw_nvg);
+
+    if (saw_mouse_x >= x && saw_mouse_y >= y && saw_mouse_x < x + w &&
+        saw_mouse_y < y + header_height && !roll->loop_input &&
+        saw_lbutton_click)
+      roll->loop_input = 1;
+
+    if (roll->loop_input && saw_lbutton_down) {
+      i32 t = (saw_mouse_x - x0 - pianokey_width - sheet_offset -
+               roll->offset_x + sheet_scale / 2) /
+              sheet_scale;
+
+      if (t <= 0)
+        roll->loop_duration = 0;
+      else
+        roll->loop_duration = (t * SAW_SAMPLE_RATE) / roll->rate;
+    }
+  }
+
+  if (!saw_lbutton_down)
+    roll->loop_input = 0;
+
   //  Piano roll
   //
 
@@ -917,7 +964,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
     if (y > frame_height - y0 - pianokey_height)
       continue;
-    if (y < frame_height - y0 - height + text_height)
+    if (y < frame_height - y0 - height + text_height + header_height)
       break;
 
     nvgBeginPath(saw_nvg);
@@ -954,7 +1001,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   if (!hover_any)
     roll->last_index = -1;
 
-  //  Offset input
+  //  Panning input
   //
 
   if (saw_mbutton_click) {
@@ -982,7 +1029,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
     if (y > frame_height - y0 - pianokey_height)
       continue;
-    if (y < frame_height - y0 - height + text_height)
+    if (y < frame_height - y0 - height + text_height + header_height)
       break;
 
     i32 h = pianokey_height;
@@ -1023,12 +1070,16 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       nvgRect(saw_nvg, x + border, y + border, w - border * 2,
               h - border * 2);
 
+      i8 turned_off = roll->pitch_turned_off[pitch] ||
+                      (roll->loop_duration > 0 &&
+                       t >= (roll->loop_duration * roll->rate) /
+                                SAW_SAMPLE_RATE);
+
       i8 has_cursor = !roll->grid_input && saw_mouse_x >= x &&
                       saw_mouse_x < x + w && saw_mouse_y >= y &&
                       saw_mouse_y < y + h;
 
-      nvgFillColor(saw_nvg, roll->pitch_turned_off[pitch]
-                                ? nvgRGBA(160, 150, 120, 100)
+      nvgFillColor(saw_nvg, turned_off ? nvgRGBA(160, 150, 120, 100)
                             : has_cursor
                                 ? nvgRGBA(180, 180, 220, 160)
                                 : nvgRGBA(170, 160, 140, 150));
@@ -1037,8 +1088,8 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       //  Empty cell input
       //
 
-      if (!roll->grid_input && !roll->pitch_turned_off[pitch] &&
-          has_cursor && saw_lbutton_click) {
+      if (!roll->grid_input && !turned_off && has_cursor &&
+          saw_lbutton_click)
         for (i32 n = 0; n < SHEET_SIZE; n++)
           if (!roll->notes[n].enabled) {
             roll->notes[n] = (saw_roll_note_t) {
@@ -1052,7 +1103,6 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
             roll->grid_time  = t;
             break;
           }
-      }
     }
   }
 
@@ -1069,7 +1119,7 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
 
     if (y + pianokey_height > frame_height - y0)
       continue;
-    if (y < frame_height - y0 - height + text_height)
+    if (y < frame_height - y0 - height + text_height + header_height)
       continue;
 
     i64 x = x0 + pianokey_width + sheet_offset + roll->offset_x +
@@ -1090,10 +1140,16 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
     //  Draw note
     //
 
+    i64 frame = saw_playback_frame;
+
+    if (frame >= roll->time && frame < roll->time + roll->duration &&
+        roll->loop_duration > 0)
+      frame -= ((frame - roll->time) / roll->loop_duration) *
+               roll->loop_duration;
+
     i8 is_playing = saw_playback_on &&
-                    saw_playback_frame >= roll->time + note->time &&
-                    saw_playback_frame <
-                        roll->time + note->time + note->duration;
+                    frame >= roll->time + note->time &&
+                    frame < roll->time + note->time + note->duration;
 
     i32 underflow = (x0 + pianokey_width + sheet_offset +
                      sheet_scale - 1 - x) /
@@ -1186,10 +1242,16 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
   //  Playback indicator
   //
   {
+    i64 frame = saw_playback_frame;
+
+    if (frame >= roll->time && frame < roll->time + roll->duration &&
+        roll->loop_duration > 0)
+      frame -= ((frame - roll->time) / roll->loop_duration) *
+               roll->loop_duration;
+
     i32 x = x0 + pianokey_width + sheet_offset + roll->offset_x -
             border * 2 +
-            ((saw_playback_frame - roll->time) * roll->rate *
-                 sheet_scale +
+            ((frame - roll->time) * roll->rate * sheet_scale +
              SAW_SAMPLE_RATE / 2) /
                 SAW_SAMPLE_RATE;
     i32 w = border * 4;
@@ -1271,13 +1333,16 @@ static void saw_init(void) {
       .notes            = { 0 },
       .time             = 0,
       .duration         = (48 * SAW_SAMPLE_RATE) / 6,
-      .grid_input       = 0,
-      .grid_note        = 0,
-      .grid_time        = 0,
-      .offset_x_input   = 0,
-      .offset_y_input   = 0,
+      .loop_duration    = 0,
       .offset_x         = 0,
       .offset_y         = ROLL_DEFAULT_OFFSET_Y,
+
+      .grid_input     = 0,
+      .grid_note      = 0,
+      .grid_time      = 0,
+      .offset_x_input = 0,
+      .offset_y_input = 0,
+      .loop_input     = 0,
     };
   }
 
@@ -1408,6 +1473,7 @@ static void saw_init(void) {
 
       SCAN_(" time %lld", 1, &roll->time);
       SCAN_(" duration %lld", 1, &roll->duration);
+      SCAN_(" loop_duration %lld", 1, &roll->loop_duration);
       SCAN_(" offset %lld %lld", 2, &roll->offset_x, &roll->offset_y);
     }
 
@@ -1565,6 +1631,7 @@ static void saw_cleanup(void) {
 
     fprintf(f, "time              %lld\n", roll->time);
     fprintf(f, "duration          %lld\n", roll->duration);
+    fprintf(f, "loop_duration     %lld\n", roll->loop_duration);
     fprintf(f, "offset            %lld %lld\n\n", roll->offset_x,
             roll->offset_y);
   }