From 3e0f2bc90645ad9f0beee41e2bee1a0a4b03013b Mon Sep 17 00:00:00 2001
From: Michael Winter <mwinter@unboundedpress.org>
Date: Mon, 30 Mar 2026 20:47:20 +0200
Subject: [PATCH] Add target register oscillations, amplitude, and fix negative
 target_register

---
 src/io.py   | 20 ++++++++++++++++++--
 src/path.py | 12 +++++++++---
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/io.py b/src/io.py
index 980583d..bfe7a9d 100644
--- a/src/io.py
+++ b/src/io.py
@@ -369,7 +369,7 @@ def main():
         "--target-register",
         type=float,
         default=0,
-        help="Target register in octaves (default: disabled, 2 = two octaves)",
+        help="Target register in octaves (default: disabled, 2 = rise 2 octaves, -2 = fall 2 octaves)",
     )
     parser.add_argument(
         "--target-register-power",
@@ -377,6 +377,18 @@ def main():
         default=1.0,
         help="Power to curve target register progress (1=linear, 2=quadratic, etc.)",
     )
+    parser.add_argument(
+        "--target-register-oscillations",
+        type=float,
+        default=0,
+        help="Number of sine wave oscillations for target register modulation (0=linear)",
+    )
+    parser.add_argument(
+        "--target-register-amplitude",
+        type=float,
+        default=0.25,
+        help="Amplitude of sine wave modulation for target register",
+    )
     parser.add_argument(
         "--allow-voice-crossing",
         action="store_true",
@@ -649,11 +661,15 @@ def main():
     weights_config["weight_dca_voice_movement"] = args.weight_dca_voice_movement
 
     # Target register
-    if args.target_register > 0:
+    if args.target_register != 0:
         weights_config["target_register"] = True
         weights_config["target_register_octaves"] = args.target_register
         weights_config["weight_target_register"] = args.weight_target_register
         weights_config["target_register_power"] = args.target_register_power
+        weights_config["target_register_oscillations"] = (
+            args.target_register_oscillations
+        )
+        weights_config["target_register_amplitude"] = args.target_register_amplitude
     else:
         weights_config["weight_target_register"] = 0  # disabled
 
diff --git a/src/path.py b/src/path.py
index cd730da..9d58e7b 100644
--- a/src/path.py
+++ b/src/path.py
@@ -6,6 +6,7 @@ Path and PathStep classes for storing path state from PathFinder.
 from __future__ import annotations
 from dataclasses import dataclass, field
 from typing import Any
+import math
 
 from .pitch import Pitch
 from .chord import Chord
@@ -378,6 +379,14 @@ class Path:
         )
         progress = len(path_chords) / max_path
         progress_curve = progress**power
+
+        oscillations = config.get("target_register_oscillations", 0)
+        amplitude = config.get("target_register_amplitude", 0.25)
+        if oscillations > 0:
+            sine_wave = math.sin(progress_curve * 2 * math.pi * oscillations)
+            modulation = amplitude * sine_wave
+            progress_curve = max(0, progress_curve + modulation)
+
         current_target = start_avg_cents + (progress_curve * target_cents)
 
         current_chord = path_chords[-1]
@@ -389,9 +398,6 @@ class Path:
             p.to_cents() for p in destination_chord.pitches
         ) / len(destination_chord.pitches)
 
-        if current_target <= 0:
-            return 1.0
-
         dist_before = abs(current_avg_cents - current_target)
         dist_after = abs(candidate_avg_cents - current_target)