I've just installed 11.04 and now at random everything freezes. The keyboard responds but the only thing that seems to unlock it is a reisub. I never had this problem before and I've had this computer for almost a year. I'm using gnome 3 but it also happens when I'm using unity. Even if I don't have any programs running soon or later it freezes. I've seen some similar questions here like this and this but no solution. 


Question: Rotating an object in OpenGL about it's centre
Answer: OpenGL uses a column vector convention, which means the matrices must be applied in the opposite of the order in which you actually want the transformations to occur.  Just replace this: 

glTranslatef(0, -y, -z);
glRotatef(angle, 1, 0, 0);
glTranslatef(0, y, z);


with this:

glTranslatef(0, y, z);
glRotatef(angle, 1, 0, 0);
glTranslatef(0, -y, -z);


and that should fix it.