From dc48c866c2449dfea5535f6333a9f3fb8c3a4076 Mon Sep 17 00:00:00 2001
From: Usu171 <usu171@proton.me>
Date: Sun, 14 Dec 2025 01:26:55 +0800
Subject: [PATCH] feat: use rotation matrix to derive acceleration ax

refs:
https://www.w3.org/TR/orientation-event/#examples
---
 src/utils/deviceOrientationInteraction.ts | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/utils/deviceOrientationInteraction.ts b/src/utils/deviceOrientationInteraction.ts
index a983f06..ea45c93 100644
--- a/src/utils/deviceOrientationInteraction.ts
+++ b/src/utils/deviceOrientationInteraction.ts
@@ -64,10 +64,7 @@ export class DeviceOrientationInteraction {
     const g = 9.8;
     const toRad = Math.PI / 180;
 
-    this.ax =
-      alpha > 180
-        ? g * Math.sin((gamma - 180) * toRad)
-        : g * Math.sin(gamma * toRad);
+    this.ax = g * Math.sin(gamma * toRad) * Math.cos(beta * toRad);
     this.ay = g * Math.sin(beta * toRad);
   }