From 887c2fbfbaa34a4b6e3adf355497b2fb05caa6fd Mon Sep 17 00:00:00 2001
From: minjaesong <alswo9628@gmail.com>
Date: Thu, 23 Apr 2026 13:35:38 +0900
Subject: [PATCH] s3m to taud fix (not emitting volcmd on note retrigger)

---
 s3m2taud.py   | 20 +++++++++++++++++++-
 terranmon.txt |  6 +++---
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/s3m2taud.py b/s3m2taud.py
index 2c6383d..b2714b0 100644
--- a/s3m2taud.py
+++ b/s3m2taud.py
@@ -660,7 +660,9 @@ def build_pattern(s3m_grid: list, ch_idx: int, default_pan: int,
         inst_vols = {}
     out = bytearray(PATTERN_BYTES)
     rows = s3m_grid[ch_idx] if ch_idx < len(s3m_grid) else [S3MRow()] * PATTERN_ROWS
-    last_inst = 0   # 1-based; tracks which instrument is loaded on this channel
+    last_inst = 0             # 1-based; tracks which instrument is loaded on this channel
+    last_note = S3M_NOTE_EMPTY  # last raw S3M note byte that was a real pitch
+    last_vol  = None            # last SEL_SET volume value (0-63), for retrigger recall
     for r, row in enumerate(rows[:PATTERN_ROWS]):
         note = encode_note(row.note)
         inst = row.inst   # S3M 1-based → Taud 1-based
@@ -668,6 +670,12 @@ def build_pattern(s3m_grid: list, ch_idx: int, default_pan: int,
         if row.inst > 0:
             last_inst = row.inst
 
+        # ── Instrument-only retrigger ──
+        # Instrument-only row: recall the last volume without touching the note.
+        retrigger = (row.inst > 0
+                     and row.note == S3M_NOTE_EMPTY
+                     and last_note not in (S3M_NOTE_EMPTY, S3M_NOTE_OFF))
+
         op, arg, vol_override, pan_override = encode_effect(
             row.effect, row.effect_arg, ch_idx, r)
 
@@ -683,11 +691,21 @@ def build_pattern(s3m_grid: list, ch_idx: int, default_pan: int,
             # so prior channel-vol state doesn't bleed through.
             vol_sel = SEL_SET
             vol_value = inst_vols.get(last_inst, 0x3F)
+        elif retrigger and last_vol is not None:
+            # Instrument-only row: re-emit the last known volume so the sample
+            # restarts at the correct level without an explicit note trigger.
+            vol_sel, vol_value = SEL_SET, last_vol
         elif vol_override is not None:
             vol_sel, vol_value = vol_override
         else:
             vol_sel, vol_value = SEL_FINE, 0   # no-op fine slide
 
+        # Track note and volume for future retrigger lookups.
+        if row.note not in (S3M_NOTE_EMPTY, S3M_NOTE_OFF):
+            last_note = row.note
+        if vol_sel == SEL_SET:
+            last_vol = vol_value
+
         # ── Pan column ──
         if pan_override is not None:
             pan_sel, pan_value = pan_override
diff --git a/terranmon.txt b/terranmon.txt
index b17dd1c..7d4dcd2 100644
--- a/terranmon.txt
+++ b/terranmon.txt
@@ -2210,9 +2210,9 @@ Rows of 16 bytes:
     Uint16  Number of patterns (0 is invalid. pattern bin length = numPats * 8 bytes)
     Uint8   Initial BPM (bias of -24. 0x00=24, 0xFF=279)
     Uint8   Initial Tickrate (0 is invalid)
-    Uint16  Current Tuning base note (0-4095), assuming octave 3. C3 (the default value) is 0x4000
-    Float32 Frequency at the base note. Default (A440) is 261.6255653
-    Byte[7] Reserved for future versions
+    Uint16  Current Tuning base note (1-4094), assuming octave 3. C3 (the default value) is 0x4000. If zero, assume the default value
+    Float32 Frequency at the base note. Default (A440) is 261.6255653. If zero, assume the default value
+    Byte[1] Reserved for future versions
 
 Taud device can queue up to 2 "playdata" in its buffer, which can be interpreted as a song.