register
Why is it unneeded? C++11 has deprecated it, c++17 removed. So, how about older (c++98)? According to Herb Sutter, it is as meaningful as whitespace. http://www.drdobbs.com/keywords-that-arent-or-comments-by-anoth/ 184403859
Actually jump require btVector3, unfortunately default argument isn't using constructor with initialization. http://bulletphysics.org/Bullet/BulletFull/classbtVector3.html#a82b4c5da54ecd4c91bd9b056dea0d288