taud: implemented eff W (panbrello)

TAUD_NOTE_EFFECTS.md

@@ -1,6 +1,6 @@
 # Taud Tracker Effect Command Reference
 
-Taud is a tracker-style music format derived from ScreamTracker 3's pattern command set, extended to 16-bit effect arguments and a 4096-tone equal-temperament pitch grid. This document defines every effect command a Taud engine must implement. Each command entry has three parts: a plain explanation for composers, compatibility notes for converting patterns from ScreamTracker 3 (ST3) or ProTracker (PT), and implementation details for engine writers.
+Taud is a tracker-style music format derived from ScreamTracker 3's pattern command set, extended to 16-bit effect arguments and a 4096-tone equal-temperament pitch grid. This document defines every effect command a Taud engine must implement. Each command entry has three parts: a plain explanation for composers, compatibility notes for converting patterns from ScreamTracker 3 (ST3), ImpulseTracker (IT) or ProTracker (PT), and implementation details for engine writers.
 
 ---
 
@@ -493,6 +493,30 @@ A tempo slide's memory slot is separate from the set-tempo path and is private t
 
 ---
 
+## W $xxyy — Panbrello (panning vibrato) with speed $xx and depth $yy
+
+**Plain.** Modulates panning with an LFO, symmetrically with H's pitch modulation. `$xx` is LFO speed, `$yy` depth; the waveform is selected by S $4x.
+
+**Compatibility.** IT `Wxy` uses nibbles; convert by nibble-repeat. IT's volume cap is $40; Taud's is $3F — very deep vibrato that would have briefly clipped at $40 in IT may clip slightly earlier in Taud. W has its own memory slot.
+
+**Implementation.** Identical machinery to H with a larger shift to fit the narrower volume range:
+
+```
+on row parse (W):
+    if (arg >> 8)  != 0: memory_W.speed = arg >> 8
+    if (arg & $FF) != 0: memory_W.depth = arg & $FF
+
+on every tick (including tick 0):
+    sine = ModSinusTable[(lfo_pos >> 2) & $3F]
+    vol_delta = (sine × memory_W.depth) >> 9
+    applied_vol = clamp(base_vol + vol_delta, 0, $3F)
+    lfo_pos = (lfo_pos + memory_W.speed × 4) & $FF
+```
+
+Peak at maximum settings: $7F × $FF >> 9 = $3F — the full panning range. Retrigger behaviour tracks the S $4x waveform nibble bit 2: cleared means retrigger on new note, set means preserve LFO position.
+
+---
+
 # The S subcommand family
 
 S is a multiplexing opcode; the **high nibble of the high byte** selects the sub-effect, and the remainder is the sub-argument.
@@ -567,6 +591,17 @@ ProTracker `E5x` maps to Taud `S $2x00` with the same index meaning.
 
 **Implementation.** As for S $3x, but applied to R's separate state (`tremolo_waveform`, `tremolo_retrigger`, and tremolo `lfo_pos`).
 
+---
+
+## S $5x00 — Panbrello LFO waveform
+
+**Plain.** Selects the shape of the panbrello (W) oscillator; value encoding is identical to S $3x.
+
+**Compatibility.** IT `S5x` maps directly.
+
+**Implementation.** As for S $3x, but applied to W's separate state (`panbrello_waveform`, `panbrello_retrigger`, and panbrello `lfo_pos`).
+
+
 ---
 
 ## S $80xx — Set channel pan position

assets/disk0/tvdos/bin/taut.js

@@ -174,7 +174,7 @@ const colEffOp = 213
 const colEffArg = 231
 const colBackPtn = 255
 
-const PITCH_PRESET_IDX = 10123 // TODO read from the Project Data section of the .taud
+const PITCH_PRESET_IDX = 240 // TODO read from the Project Data section of the .taud
 
 Number.prototype.hex02 = function() {
     return this.toString(16).toUpperCase().padStart(2,'0')

tsvm_core/src/net/torvald/tsvm/peripheral/AudioAdapter.kt

@@ -1088,7 +1088,8 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
     //                H=0x11 vibrato, I=0x12 tremor, J=0x13 arpeggio,
     //                K=0x14 K, L=0x15 L, O=0x18 sample offset,
     //                Q=0x1A retrig, R=0x1B tremolo, S=0x1C subcommands,
-    //                T=0x1D tempo, U=0x1E fine vibrato, V=0x1F global vol).
+    //                T=0x1D tempo, U=0x1E fine vibrato, V=0x1F global vol,
+    //                W=0x20 panbrello).
     //   K (0x14) and L (0x15) are intentionally no-op in the engine — the
     //   converter is required to split them into a recall-only H/G plus a
     //   volume-column slide cell.
@@ -1152,6 +1153,7 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
         const val OP_T = 0x1D
         const val OP_U = 0x1E
         const val OP_V = 0x1F
+        const val OP_W = 0x20
     }
 
     private fun computePlaybackRate(inst: TaudInst, noteVal: Int): Double =
@@ -1241,9 +1243,10 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
         }
         voice.rowVolume = voice.channelVolume
         voice.noteWasCut = false
-        // Vibrato/tremolo retrigger: reset LFO position when waveform requests it.
+        // Vibrato/tremolo/panbrello retrigger: reset LFO position when waveform requests it.
         if (voice.vibratoRetrig) voice.vibratoLfoPos = 0
         if (voice.tremoloRetrig) voice.tremoloLfoPos = 0
+        if (voice.panbrelloRetrig) voice.panbrelloLfoPos = 0
     }
 
     private fun applyVolColumn(voice: Voice, value: Int, sel: Int) {
@@ -1301,6 +1304,7 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
             voice.tremorOn = 0
             voice.vibratoActive = false
             voice.tremoloActive = false
+            voice.panbrelloActive = false
             voice.retrigActive = false
             voice.tempoSlideDir = 0
             voice.volColSlideUp = 0; voice.volColSlideDown = 0
@@ -1471,6 +1475,13 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
                 val hi = (rawArg ushr 8) and 0xFF
                 playhead.globalVolume = hi
             }
+            EffectOp.OP_W -> {
+                val sp = (rawArg ushr 8) and 0xFF
+                val dp = rawArg and 0xFF
+                if (sp != 0) voice.mem.wSpeed = sp
+                if (dp != 0) voice.mem.wDepth = dp
+                voice.panbrelloActive = true
+            }
         }
     }
 
@@ -1486,6 +1497,7 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
             }
             0x3 -> { voice.vibratoWave = x and 3; voice.vibratoRetrig = (x and 4) == 0 }
             0x4 -> { voice.tremoloWave = x and 3; voice.tremoloRetrig = (x and 4) == 0 }
+            0x5 -> { voice.panbrelloWave = x and 3; voice.panbrelloRetrig = (x and 4) == 0 }
             0x8 -> {
                 // S$80xx — full 8-bit pan; arg low byte is the value.
                 voice.channelPan = arg and 0xFF
@@ -1609,6 +1621,14 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
                 voice.tremoloLfoPos = (voice.tremoloLfoPos + voice.mem.rSpeed * 4) and 0xFF
             }
 
+            // Panbrello (W) — modulates panning around base.
+            if (voice.panbrelloActive) {
+                val sine = lfoSample(voice.panbrelloLfoPos, voice.panbrelloWave)
+                val panDelta = (sine * voice.mem.wDepth) shr 9
+                voice.rowPan = ((voice.channelPan ushr 2) + panDelta).coerceIn(0, 0x3F)
+                voice.panbrelloLfoPos = (voice.panbrelloLfoPos + voice.mem.wSpeed * 4) and 0xFF
+            }
+
             // Arpeggio (J) — overrides pitchToMixer for this tick (overlay on basePitch).
             if (voice.arpActive) {
                 val voiceIdx = ts.tickInRow % 3
@@ -1846,6 +1866,9 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
         // R (tremolo) — private speed and depth.
         var rSpeed: Int = 0
         var rDepth: Int = 0
+        // W (panbrello) — private speed and depth.
+        var wSpeed: Int = 0
+        var wDepth: Int = 0
         // Private slots
         var d: Int = 0
         var i: Int = 0
@@ -1907,6 +1930,12 @@ class AudioAdapter(val vm: VM) : PeriBase(VM.PERITYPE_SOUND) {
         var tremoloWave = 0
         var tremoloRetrig = true
 
+        // Panbrello (W) — uses memW.
+        var panbrelloActive = false
+        var panbrelloLfoPos = 0
+        var panbrelloWave = 0
+        var panbrelloRetrig = true
+
         // Glissando flag (S$1x).
         var glissandoOn = false