bluebey-studio: 思考の雲の半円に、決まったゆらぎを入れて大きさを揃えすぎないように

半円の大きさを0.72〜1.28倍の範囲でインデックス由来の決まった値でゆらがせる（プレビュー・書き出しで同じ絵になる）。

1 files changed, 18 insertions, 2 deletions

diff --git a/public/bluebey-studio/src/caption.js b/public/bluebey-studio/src/caption.js
index 08b962f..821ccb5 100644
--- a/public/bluebey-studio/src/caption.js
+++ b/public/bluebey-studio/src/caption.js
@@ -827,6 +827,7 @@ function thinkEdges(box, scale) {
   const amp = Math.min((perimeter / count) * 0.55, Math.min(w, h) * 0.26);
 
   const edges = [];
+  let outer = amp;
   for (let i = 0; i < points.length; i++) {
     const a = points[i];
     const b = points[(i + 1) % points.length];
@@ -844,9 +845,13 @@ function thinkEdges(box, scale) {
       nx = -nx;
       ny = -ny;
     }
-    edges.push(scallopEdge(a, b, { x: nx, y: ny }, amp));
+    // A small, *deterministic* wobble so the scallops are not all identical - the
+    // even size read as too regular. Same index, same bubble, every render.
+    const scallopAmp = amp * (0.72 + 0.56 * scallopJitter(i));
+    if (scallopAmp > outer) outer = scallopAmp;
+    edges.push(scallopEdge(a, b, { x: nx, y: ny }, scallopAmp));
   }
-  return { edges, amp };
+  return { edges, amp: outer };
 }
 
 /** A closed cloud, followed by the tail: two or three shrinking puffs. */
@@ -905,6 +910,17 @@ function scallopEdge(from, to, normal, amp) {
   );
 }
 
+/**
+ * A small deterministic wobble in 0..1 for the i-th scallop of a cloud.
+ *
+ * It is derived from the index alone, so a bubble draws its scallops exactly
+ * the same in the live preview, a screenshot, and the SVG export.
+ */
+function scallopJitter(i) {
+  const x = Math.sin((i + 1) * 12.9898) * 43758.5453;
+  return x - Math.floor(x);
+}
+
 /** A circle as `M`/`C`/`Z` commands, so it can join the bubble's one path. */
 function circleCommands(cx, cy, r) {
   const k = r * KAPPA;