From 5b2f8b7979d2fb0b8e0f5be175fdc8651e987bdf Mon Sep 17 00:00:00 2001
From: Yasutake Yohei <61961825+yasutakeyohei@users.noreply.github.com>
Date: Thu, 22 Oct 2026 14:49:49 +0900
Subject: bluebey-studio: 後ろから口が見える・壁で隠れない問題を修正
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口を閉じた舌出しのときだけ深度テストを外していたが、後ろ姿や見えない壁では常に深度テストを有効に戻すようにした。
---
 public/bluebey-studio/src/main.js | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/public/bluebey-studio/src/main.js b/public/bluebey-studio/src/main.js
index b08ea11..bdf5697 100644
--- a/public/bluebey-studio/src/main.js
+++ b/public/bluebey-studio/src/main.js
@@ -1370,6 +1370,8 @@ async function init() {
   const warmupUntil = performance.now() + 2500;
 
   let snotSignature = null;
+  const mouthNormal = new THREE.Vector3();
+  const mouthToCamera = new THREE.Vector3();
   const loop = (now) => {
     const rawDelta = now - last;
     const dt = Math.min(0.05, rawDelta / 1000);
@@ -1414,6 +1416,28 @@ async function init() {
     }
     if (face.flush(now, 26)) app.needsRender = true;
 
+    // The mouth artwork normally lets a closed-lip tongue win the depth test so
+    // it reads over the 3D nose. That would also draw it through the back of the
+    // head and over a 見えない壁, so switch depth testing back on when the camera
+    // is behind the face or a wall is in play.
+    const mouthMesh = model.parts.mouthMesh;
+    if (mouthMesh?.material) {
+      const mouth = state.face.mouth ?? {};
+      const tongueOverLip = (mouth.round ?? 0) <= 0.004
+        && (mouth.open ?? 0) <= 0.004
+        && (mouth.tongue ?? 1) > 0.01;
+      mouthMesh.getWorldDirection(mouthNormal);
+      mouthMesh.getWorldPosition(mouthToCamera);
+      mouthToCamera.subVectors(view.camera.position, mouthToCamera);
+      const facing = mouthNormal.dot(mouthToCamera) > 0;
+      const wallOn = state.render.wall?.on === true || state.render.wall2?.on === true;
+      const depthTest = !tongueOverLip || !facing || wallOn;
+      if (mouthMesh.material.depthTest !== depthTest) {
+        mouthMesh.material.depthTest = depthTest;
+        app.needsRender = true;
+      }
+    }
+
     view.controls.update(dt);
 
     const animating = (state.anim.mode ?? 'off') !== 'off'
-- 
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