Traditional physics simulation in games or graphics industry was basically discrete. But engines nowadays such as box2d or bullet3d implement continuous physics simulation. I know basic principles of discrete simulation, but I have no idea about continuous simulation. That's magical to me, and using magic is hard and dangerous. So I want to make the magic into tools by understanding them.
So I want to know: (1) What are the basic ideas and implementation principles of these continuous physics simulations? (2) Could the idea be generalized to other kind of discrete simulation? Please let me understand this!