From 371b4523a400d0c888dbefb7111a467e1f86c0f7 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Tue, 8 Jun 2021 14:53:21 +0200
Subject: Add channel muting

---
 src/sequencer.c | 65 ++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 21 deletions(-)

(limited to 'src/sequencer.c')

diff --git a/src/sequencer.c b/src/sequencer.c
index dc3249c..526680a 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -4,6 +4,7 @@
 //
 // Color indexes.
 //
+
 #define COL_BG   0
 #define COL_FG   1
 #define COL_RED  2
@@ -104,15 +105,6 @@ static const u32 channel_buttons[] = {
     0x0f080808, 0x0808080f,
 };
 
-//
-// Globals.
-//
-static int bpm = 115;
-static int step_counter = 0;
-int trig_selection_loc = 0;
-int param_selection_loc = 64;
-int channel_selection_loc = 0;
-
 //
 // Wave data.
 //
@@ -139,6 +131,16 @@ static const u8 square_wave[16] = {
     0x00, 0x00, 0x00, 0x00,
 };
 
+//
+// Globals.
+//
+
+static int bpm = 115;
+static int step_counter = 0;
+int trig_selection_loc = 0;
+int param_selection_loc = 64;
+int channel_selection_loc = 0;
+
 // TODO: Split into individual trigger types.
 typedef struct SeqTrigger {
     bool trigger;
@@ -216,6 +218,11 @@ static SeqTrigger sequences[3][16] = {
     },
 };
 
+static bool active_channels[4] = {true, true, true, true};
+
+//
+// Trigger render functions.
+//
 
 #define TRIG_W 15
 #define TRIG_H 24
@@ -276,6 +283,10 @@ draw_triggers(void) {
     }
 }
 
+//
+// Channel render functions.
+//
+
 #define CHAN_W 19
 #define CHAN_H 8
 #define CHAN_START_X 35
@@ -290,10 +301,11 @@ draw_channels(void) {
     unpack_tiles(channel_buttons, channel_tiles, 3 * 4);
     size_t k = 0;
     for (size_t i = 0; i < 4; i++) {
+        u8 clr = active_channels[i] ? COL_FG : COL_GREY;
         size_t y = CHAN_START_Y + i * CHAN_OFFSET_Y;
-        draw_tile(CHAN_START_X, y, channel_tiles + k++, COL_FG, false);
-        draw_tile(CHAN_START_X + 8, y, channel_tiles + k++, COL_FG, false);
-        draw_tile(CHAN_START_X + 16, y, channel_tiles + k++, COL_FG, false);
+        draw_tile(CHAN_START_X, y, channel_tiles + k++, clr, false);
+        draw_tile(CHAN_START_X + 8, y, channel_tiles + k++, clr, false);
+        draw_tile(CHAN_START_X + 16, y, channel_tiles + k++, clr, false);
     }
 }
 
@@ -308,9 +320,9 @@ draw_channel_cursor(size_t i, u8 clr) {
 }
 
 void
-irq_timer_0(void) {
+irq_timer(void) {
     Note active_note;
-    {
+    if (active_channels[0]) {
         SeqTrigger *trig = &sequences[0][step_counter];
         active_note = trig->note;
         if (trig->trigger) {
@@ -324,8 +336,11 @@ irq_timer_0(void) {
             SOUND_SQUARE1_FREQ = SOUND_FREQ_RESET
                 | sound_rates[active_note];
         }
+    } else {
+        SOUND_SQUARE1_CTRL = 0;
+        SOUND_SQUARE1_FREQ = 0;
     }
-    {
+    if (active_channels[1]) {
         SeqTrigger *trig = &sequences[1][step_counter];
         active_note = trig->note;
         if (trig->trigger) {
@@ -336,8 +351,11 @@ irq_timer_0(void) {
             SOUND_SQUARE2_FREQ = SOUND_FREQ_RESET
                 | sound_rates[active_note];
         }
+    } else {
+        SOUND_SQUARE2_CTRL = 0;
+        SOUND_SQUARE2_FREQ = 0;
     }
-    {
+    if (active_channels[2]) {
         SeqTrigger *trig = &sequences[2][step_counter];
         active_note = trig->note;
         if (trig->trigger) {
@@ -391,6 +409,9 @@ irq_timer_0(void) {
             SOUND_WAVE_FREQ = SOUND_FREQ_RESET
                 | sound_rates[active_note];
         }
+    } else {
+        SOUND_WAVE_CTRL = 0;
+        SOUND_WAVE_FREQ = 0;
     }
     step_counter = (step_counter + 1) % 16;
 }
@@ -404,7 +425,7 @@ set_time(int bpm) {
     // We have to operate on integer values, so the numbers have been
     // precalculated to `n_ticks = 244181 / bmp`
     int n_ticks = -244181 / bpm;
-    irs_set(IRQ_TIMER_0, irq_timer_0);
+    irs_set(IRQ_TIMER_0, irq_timer);
     TIMER_DATA_0 = n_ticks;
     TIMER_CTRL_0 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
 }
@@ -419,14 +440,17 @@ void handle_channel_cursor(void);
 
 void
 handle_channel_cursor(void) {
+    if (key_tap(KEY_B)) {
+        active_channels[channel_selection_loc] ^= 1;
+        draw_channels();
+    }
     if (key_tap(KEY_RIGHT)) {
         trig_selection_loc = 0;
         param_selection_loc = 0;
         input_handler = handle_trigger_cursor;
         draw_channel_cursor(channel_selection_loc, COL_GREY);
         draw_trig_cursor(trig_selection_loc, COL_BLUE);
-    }
-    if (key_tap(KEY_UP)) {
+    } else if (key_tap(KEY_UP)) {
         draw_channel_cursor(channel_selection_loc, COL_BG);
         if (channel_selection_loc == 0) {
             channel_selection_loc = SEQ_N_CHANNELS - 1;
@@ -435,8 +459,7 @@ handle_channel_cursor(void) {
         }
         draw_channel_cursor(channel_selection_loc, COL_BLUE);
         draw_triggers();
-    }
-    if (key_tap(KEY_DOWN)) {
+    } else if (key_tap(KEY_DOWN)) {
         draw_channel_cursor(channel_selection_loc, COL_BG);
         if (channel_selection_loc == SEQ_N_CHANNELS - 1) {
             channel_selection_loc = 0;
-- 
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