diff --git a/src/Mono.cs b/src/Mono.cs
index 497c8bd..9846c1d 100644
--- a/src/Mono.cs
+++ b/src/Mono.cs
@@ -52,7 +52,7 @@ static class Mono
         {
             if (Input.Key(Key.MouseCenter).IsActive())
             {
-                float sx = Maths.s_scalar(Input.Mouse.pos.x / 640);
+                float sx = Input.Mouse.posChange.x;
                 float ssx = Maths.smooth_start(sx);
                 box_pose.orientation *= Quat.FromAngles(0, sx * 180.0f * Time.Stepf, 0);
             }