From c891299737dd0c73a54f9bd1510dc00d6f140f1f Mon Sep 17 00:00:00 2001
From: Yasutake Yohei <61961825+yasutakeyohei@users.noreply.github.com>
Date: Thu, 22 Oct 2026 14:58:33 +0900
Subject: bluebey-studio: 横から見たとき口が体を透ける問題を修正
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正面判定を内積>0から>0.5に変更し、真横（内積がほぼ0）では深度テストを有効に戻すようにした。
---
 public/bluebey-studio/src/main.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'public')

diff --git a/public/bluebey-studio/src/main.js b/public/bluebey-studio/src/main.js
index 9178427..6507bf4 100644
--- a/public/bluebey-studio/src/main.js
+++ b/public/bluebey-studio/src/main.js
@@ -1428,8 +1428,11 @@ async function init() {
         && (mouth.tongue ?? 1) > 0.01;
       mouthMesh.getWorldDirection(mouthNormal);
       mouthMesh.getWorldPosition(mouthToCamera);
-      mouthToCamera.subVectors(view.camera.position, mouthToCamera);
-      const facing = mouthNormal.dot(mouthToCamera) > 0;
+      mouthToCamera.subVectors(view.camera.position, mouthToCamera).normalize();
+      // Only let the artwork win the depth test when the camera is actually in
+      // front of the face. At a side view the dot product is near zero, and the
+      // mouth must lose to the body (or it shows through the far side).
+      const facing = mouthNormal.dot(mouthToCamera) > 0.5;
       const wallOn = state.render.wall?.on === true || state.render.wall2?.on === true;
       const depthTest = !tongueOverLip || !facing || wallOn;
       if (mouthMesh.material.depthTest !== depthTest) {
-- 
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