From 1c3595cb5be803fe1325de65017d250e53b739cd Mon Sep 17 00:00:00 2001
From: Mistium <92952823+Mistium@users.noreply.github.com>
Date: Thu, 24 Sep 2026 02:35:47 +0100
Subject: [PATCH] Tolerate a drawable without a skin when fencing a position

A target can move while its skin is still loading or after the skin was destroyed. getFencedPositionOfDrawable already tolerated a missing drawable but dereferenced the skin unconditionally, so a "go to" block on such a target threw "Cannot read properties of undefined (reading 'getFenceBounds')". Keep the requested position when there is nothing to fence against.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---
 src/RenderWebGL.js                        | 9 ++++++++-
 test/unit/RenderWebGLOptimizationTests.js | 8 ++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/RenderWebGL.js b/src/RenderWebGL.js
index 28fec5f7e..54bb09cf8 100644
--- a/src/RenderWebGL.js
+++ b/src/RenderWebGL.js
@@ -1880,9 +1880,16 @@ class RenderWebGL extends EventEmitter {
             return [x, y];
         }
 
+        const skin = drawable._skin;
+        if (!skin) {
+            // A target can move while its skin is still loading or after it was destroyed.
+            // There is nothing to fence against, so keep the requested position.
+            return [x, y];
+        }
+
         const dx = x - drawable._position[0];
         const dy = y - drawable._position[1];
-        const aabb = drawable._skin.getFenceBounds(drawable, __fenceBounds);
+        const aabb = skin.getFenceBounds(drawable, __fenceBounds);
         const inset = Math.floor(Math.min(aabb.width, aabb.height) / 2);
 
         const sx = this._xRight - Math.min(FENCE_WIDTH, inset);
diff --git a/test/unit/RenderWebGLOptimizationTests.js b/test/unit/RenderWebGLOptimizationTests.js
index 2711883af..dcab93a2b 100644
--- a/test/unit/RenderWebGLOptimizationTests.js
+++ b/test/unit/RenderWebGLOptimizationTests.js
@@ -40,3 +40,11 @@ test('skin sizes tolerate asynchronous loading and destroyed skins', t => {
     t.same(renderer.getSkinSize(123), [0, 0]);
     t.end();
 });
+
+test('fencing keeps the requested position while a drawable has no skin', t => {
+    const renderer = Object.create(RenderWebGL.prototype);
+    renderer._allDrawables = [{_position: [0, 0], _skin: null}];
+    t.same(renderer.getFencedPositionOfDrawable(0, [500, -400]), [500, -400]);
+    t.same(renderer.getFencedPositionOfDrawable(7, [12, 34]), [12, 34]);
+    t.end();
+});