fixed trackball as quat

Former-commit-id: b54936be912ffc00cdd83fb8149eb1260136e44f

tutorial/401_BiharmonicDeformation/main.cpp

@@ -112,7 +112,7 @@ int main(int argc, char *argv[])
   viewer.data.set_mesh(U, F);
   viewer.core.show_lines = false;
   viewer.data.set_colors(C);
-  viewer.core.trackball_angle << 0,sqrt(2.0),0,sqrt(2.0);
+  viewer.core.trackball_angle = Eigen::Quaternionf(sqrt(2.0),0,sqrt(2.0),0);
   viewer.core.trackball_angle.normalize();
   viewer.callback_pre_draw = &pre_draw;
   viewer.callback_key_down = &key_down;

tutorial/402_PolyharmonicDeformation/main.cpp

@@ -96,7 +96,7 @@ int main(int argc, char *argv[])
   viewer.data.set_mesh(U, F);
   viewer.core.show_lines = false;
   viewer.data.set_colors(C);
-  viewer.core.trackball_angle << -0.58,-0.03,-0.03,0.81;
+  viewer.core.trackball_angle = Eigen::Quaternionf(0.81,-0.58,-0.03,-0.03);
   viewer.core.trackball_angle.normalize();
   viewer.callback_pre_draw = &pre_draw;
   viewer.callback_key_down = &key_down;

tutorial/403_BoundedBiharmonicWeights/main.cpp

@@ -168,7 +168,6 @@ int main(int argc, char *argv[])
   viewer.core.show_lines = false;
   viewer.core.show_overlay_depth = false;
   viewer.core.line_width = 1;
-  viewer.core.trackball_angle.normalize();
   viewer.callback_pre_draw = &pre_draw;
   viewer.callback_key_down = &key_down;
   viewer.core.is_animating = false;