From 0a87451b6d62935654100971a55ffd8bb521acdf Mon Sep 17 00:00:00 2001
From: Simon Leistikow <s_leis06@uni-muenster.de>
Date: Wed, 13 Sep 2017 15:11:23 +0200
Subject: [PATCH] Add missing mutex

---
 .../java/de/trac/spherical/rendering/SphereSurfaceView.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/de/trac/spherical/rendering/SphereSurfaceView.java b/app/src/main/java/de/trac/spherical/rendering/SphereSurfaceView.java
index b0be570..86da86a 100644
--- a/app/src/main/java/de/trac/spherical/rendering/SphereSurfaceView.java
+++ b/app/src/main/java/de/trac/spherical/rendering/SphereSurfaceView.java
@@ -58,8 +58,10 @@ public class SphereSurfaceView extends GLSurfaceView implements SensorEventListe
                 if (x < getWidth() / 2)
                     dy = dy * -1 ;
 
-                Matrix.rotateM(rotationMatrix, 0, dy * TOUCH_SCALE_FACTOR, 1.0f, 0.0f, 0.0f);
-                Matrix.rotateM(rotationMatrix, 0, dx * TOUCH_SCALE_FACTOR, 0.0f, 1.0f, 0.0f);
+                synchronized (rotationMatrix) {
+                    Matrix.rotateM(rotationMatrix, 0, dy * TOUCH_SCALE_FACTOR, 1.0f, 0.0f, 0.0f);
+                    Matrix.rotateM(rotationMatrix, 0, dx * TOUCH_SCALE_FACTOR, 0.0f, 1.0f, 0.0f);
+                }
         }
 
         previousX = x;