From c1b2d6d9964667465d69efd9450e044a6785e729 Mon Sep 17 00:00:00 2001
From: Dejvino <dejvino@gmail.com>
Date: Mon, 16 Feb 2026 23:06:36 +0100
Subject: [PATCH] fix theme indexing

---
 RP2040_Tracker.ino | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/RP2040_Tracker.ino b/RP2040_Tracker.ino
index 7f8adff..145a776 100644
--- a/RP2040_Tracker.ino
+++ b/RP2040_Tracker.ino
@@ -61,6 +61,7 @@ UIState currentState = UI_MENU_MAIN;
 const char* mainMenu[] = { "Tracker", "Randomize", "Setup" };
 const int mainMenuCount = sizeof(mainMenu) / sizeof(char*);
 const char* randomizeMenu[] = { "Back", "Scale", "Melody", "Mutation", "Song Mode", "Theme 1", "Theme 2", "Theme 3", "Theme 4", "Theme 5", "Theme 6", "Theme 7" };
+const int THEME_1_INDEX = 5;
 const int randomizeMenuCount = sizeof(randomizeMenu) / sizeof(char*);
 const char* setupMenu[] = { "Back", "Channel", "Tempo", "Save", "Load" };
 const int setupMenuCount = sizeof(setupMenu) / sizeof(char*);
@@ -68,7 +69,8 @@ const int setupMenuCount = sizeof(setupMenu) / sizeof(char*);
 int menuSelection = 0;
 volatile int navigationSelection = 1;
 volatile int playbackStep = 0;
-volatile int midiChannel = 1;
+int midiChannel = 1;
+volatile int shMidiChannel = midiChannel;
 int scaleNotes[12];
 int numScaleNotes = 0;
 int melodySeed = 0;
@@ -170,6 +172,7 @@ bool loadSequence() {
   if (magic != EEPROM_MAGIC) return false;
   
   EEPROM.get(addr, midiChannel); addr += sizeof(midiChannel);
+  shMidiChannel = midiChannel;
   EEPROM.get(addr, melodySeed); addr += sizeof(melodySeed);
 
   EEPROM.get(addr, numScaleNotes); addr += sizeof(numScaleNotes);
@@ -240,7 +243,7 @@ void setup() {
 }
 
 void sendMidi(uint8_t status, uint8_t note, uint8_t velocity) {
-  uint8_t channelStatus = status | (midiChannel - 1);
+  uint8_t channelStatus = status | (shMidiChannel - 1);
   Serial1.write(channelStatus);
   Serial1.write(note);
   Serial1.write(velocity);
@@ -359,6 +362,7 @@ void handleInput() {
         midiChannel += (delta > 0 ? 1 : -1);
         if (midiChannel < 1) midiChannel = 16;
         if (midiChannel > 16) midiChannel = 1;
+        shMidiChannel = midiChannel;
         break;
       case UI_SETUP_TEMPO_EDIT:
         tempo += delta;
@@ -438,15 +442,16 @@ void handleInput() {
                   }
                 }
               }
-              if (menuSelection >= 5) { // Themes
+              if (menuSelection >= THEME_1_INDEX) { // Themes
+                const int selectedTheme = menuSelection - THEME_1_INDEX + 1;
                 if (isPlaying) {
-                  queuedTheme = menuSelection - 2;
+                  queuedTheme = selectedTheme;
                   mutex_enter_blocking(&midiMutex);
                   generateSequenceData(queuedTheme, nextSequence);
                   nextSequenceReady = true;
                   mutex_exit(&midiMutex);
                 } else {
-                  generateTheme(menuSelection - 2);
+                  generateTheme(selectedTheme);
                 }
               }
               break;
@@ -612,12 +617,12 @@ void drawMenu(const char* title, const char* items[], int count, int selection)
     }
 
     // Special case for queued theme
-    if (currentState == UI_MENU_RANDOMIZE && i >= 5 && queuedTheme == (i - 4)) {
+    if (currentState == UI_MENU_RANDOMIZE && i >= THEME_1_INDEX && queuedTheme == (i - THEME_1_INDEX + 1)) {
         display.print(F(" [NEXT]"));
     }
 
     // Special case for active theme
-    if (currentState == UI_MENU_RANDOMIZE && i >= 5 && currentThemeIndex == (i - 4)) {
+    if (currentState == UI_MENU_RANDOMIZE && i >= THEME_1_INDEX && currentThemeIndex == (i - THEME_1_INDEX + 1)) {
         display.print(F(" *"));
     }