All sizes are relative to resolution, and the calculation
is not wanted in real time, therefore it is cached, update
the cached size with this function.
Inputes the object that is currently hovered, this function
updates this object accordingly (i.e. if it's the object
being inputted one thing happens, and not, another).
Update Resolution, should be called every time the resolution
of the OpenGL screen has been changed, this is because it needs
to re-cache all its actual sizes
Needs no input since screen resolution is global.