From 504e30e052391d9f7c90c0ea017bd52f6b743840 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Tue, 16 Sep 2025 14:19:54 +0000
Subject: [PATCH] This commit enhances the tunnel screensaver with two new
 features:

1.  The tunnel now draws "off-screen" by increasing the maximum radius of the concentric shapes. This creates a more immersive effect.
2.  The center of the tunnel now moves in a smooth, circular path, simulating the effect of going around bends. This is achieved by using `awk` to perform trigonometric calculations for the center coordinates in each frame.

The `awk` calls have been optimized to run in a single process per frame for better performance.
---
 gallery/tunnel/tunnel.sh | 22 +++++++++++++++++++---
 jury/tunnel.bats         |  0
 2 files changed, 19 insertions(+), 3 deletions(-)
 mode change 100644 => 100755 jury/tunnel.bats

diff --git a/gallery/tunnel/tunnel.sh b/gallery/tunnel/tunnel.sh
index d50556e..375605d 100755
--- a/gallery/tunnel/tunnel.sh
+++ b/gallery/tunnel/tunnel.sh
@@ -30,9 +30,14 @@ animate() {
     width=$(tput cols)
     local height
     height=$(tput lines)
-    local center_x=$((width / 2))
-    local center_y=$((height / 2))
-    local max_radius=$(( (height > width ? height : width) / 2 + 2 ))
+    local original_center_x=$((width / 2))
+    local original_center_y=$((height / 2))
+    local center_x=$original_center_x
+    local center_y=$original_center_y
+    local center_offset_x=$((width / 4))
+    local center_offset_y=$((height / 4))
+    local angle=0
+    local max_radius=$((width + height))
     local ribbon_spacing=7
     local -a radii=()
     local frame_counter=0
@@ -55,6 +60,17 @@ animate() {
     }
 
     while true; do
+        # --- Update center coordinates for a moving tunnel effect (more efficiently) ---
+        read -r angle center_x center_y < <(awk -v angle="$angle" \
+            -v center_x="$original_center_x" -v center_y="$original_center_y" \
+            -v offset_x="$center_offset_x" -v offset_y="$center_offset_y" \
+            'BEGIN {
+                angle += 0.05;
+                cx = int(center_x + offset_x * cos(angle));
+                cy = int(center_y + offset_y * sin(angle));
+                print angle, cx, cy;
+            }')
+
         frame_buffer=""
         # Add a new ribbon every few frames
         if (( frame_counter % ribbon_spacing == 0 )); then
diff --git a/jury/tunnel.bats b/jury/tunnel.bats
old mode 100644
new mode 100755