From 8c91e5d45d31a5c7c836032112f83d3235f738a8 Mon Sep 17 00:00:00 2001
From: Mitya Selivanov <automainint@guattari.tech>
Date: Sun, 1 Oct 2023 18:28:03 +0200
Subject: Sheet rate fixes

---
 TODO              |  3 +--
 source/saw/main.c | 32 ++++++++++++++++++++------------
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/TODO b/TODO
index 7f840ed..bd872f3 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,8 @@
 To-Do list
 
 - Grid size changing
-- UI: Playback controls
+- Playback: BPM, Volume
 - UI: Effects stack
-- UI: Volume control
 - Sound: Simple tonal synth
 - Sound: Kick, snare, cymbal
 - UI: Catalog
diff --git a/source/saw/main.c b/source/saw/main.c
index d67efd1..0cb30d3 100644
--- a/source/saw/main.c
+++ b/source/saw/main.c
@@ -39,6 +39,7 @@ enum {
   UNISON_COUNT = 100,
   SHEET_SIZE   = 200,
 
+  ROLL_DEFAULT_RATE     = 8,
   ROLL_DEFAULT_OFFSET_Y = 710,
 
   INSTRUMENT_SINE = 0,
@@ -526,13 +527,14 @@ static void saw_ui_compose(i64 x0, i64 y0, i64 width, i64 height) {
           .enabled          = 1,
           .track            = track,
           .pitch_turned_off = { 0 },
-          .rate             = 6,
+          .rate             = ROLL_DEFAULT_RATE,
           .notes            = { 0 },
           .time             = frame,
-          .duration         = (6 * SAW_SAMPLE_RATE) / grid_rate,
-          .loop_duration    = 0,
-          .offset_x         = 0,
-          .offset_y         = ROLL_DEFAULT_OFFSET_Y,
+          .duration         = (ROLL_DEFAULT_RATE * SAW_SAMPLE_RATE) /
+                      grid_rate,
+          .loop_duration = 0,
+          .offset_x      = 0,
+          .offset_y      = ROLL_DEFAULT_OFFSET_Y,
 
           .last_index     = -1,
           .grid_input     = 0,
@@ -953,7 +955,8 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       if (t <= 0)
         roll->loop_duration = 0;
       else
-        roll->loop_duration = (t * SAW_SAMPLE_RATE) / roll->rate;
+        roll->loop_duration = (t * SAW_SAMPLE_RATE + roll->rate / 2) /
+                              roll->rate;
     }
   }
 
@@ -1058,8 +1061,10 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       for (i32 n = 0; n < SHEET_SIZE; n++) {
         saw_roll_note_t *p = roll->notes + n;
         if (p->enabled && p->pitch == pitch &&
-            t >= (p->time * roll->rate) / SAW_SAMPLE_RATE &&
-            t < ((p->time + p->duration) * roll->rate) /
+            t >= (p->time * roll->rate + SAW_SAMPLE_RATE / 2) /
+                     SAW_SAMPLE_RATE &&
+            t < ((p->time + p->duration) * roll->rate +
+                 SAW_SAMPLE_RATE / 2) /
                     SAW_SAMPLE_RATE) {
           note = n;
           break;
@@ -1134,8 +1139,11 @@ static void saw_ui_roll(saw_roll_t *roll, i64 x0, i64 y0, i64 width,
       continue;
 
     i64 x = x0 + pianokey_width + sheet_offset + roll->offset_x +
-            (note->time * roll->rate * sheet_scale) / SAW_SAMPLE_RATE;
-    i64 w = (note->duration * roll->rate * sheet_scale) /
+            (note->time * roll->rate * sheet_scale +
+             SAW_SAMPLE_RATE / 2) /
+                SAW_SAMPLE_RATE;
+    i64 w = (note->duration * roll->rate * sheet_scale +
+             SAW_SAMPLE_RATE / 2) /
             SAW_SAMPLE_RATE;
     i32 h = pianokey_height;
 
@@ -1340,10 +1348,10 @@ static void saw_init(void) {
       .track            = 0,
       .last_index       = -1,
       .pitch_turned_off = { 0 },
-      .rate             = 6,
+      .rate             = ROLL_DEFAULT_RATE,
       .notes            = { 0 },
       .time             = 0,
-      .duration         = (48 * SAW_SAMPLE_RATE) / 6,
+      .duration         = (48 * SAW_SAMPLE_RATE) / ROLL_DEFAULT_RATE,
       .loop_duration    = 0,
       .offset_x         = 0,
       .offset_y         = ROLL_DEFAULT_OFFSET_Y,
-- 
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