Fix the FaceDown button.

When the device is placed into 'face down' position, the top should
point away from the user. This was really confusing me until I found
it.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/ui/accelerometercontrol.cpp b/src/ui/accelerometercontrol.cpp
index d4656f6..1a65afc 100644
--- a/src/ui/accelerometercontrol.cpp
+++ b/src/ui/accelerometercontrol.cpp
@@ -63,6 +63,9 @@ void AccelerometerControl::setValue(const QVector3D &newValue)
         mRotation = QQuaternion();
     } else if(dot < -0.999) {
         mRotation = QQuaternion::fromAxisAndAngle(0, 0, 1, 180);
+    } else if (target.z() == -1) {
+        // special case for face down (mirror of face up, not with the top pointing down)
+        mRotation = QQuaternion(0.0, 0.0, -0.707107, -0.707107);
     } else {
         // we want the quaternion that transforms target into up
         QVector3D cross = QVector3D::crossProduct(target, accelerometerY);