Here Devs, When we are about to create a game with real world effects like physics action ,we need to put some extra effort to accomplish this task, To reduce this Work, Box2D is an excellent Open Source Physics engine to simulate real world effects,we can easily integrate this with our projects and make our game as wonderful physics simulated projects ,Here is the link for Box2D Sites http://www.box2d.org/ .So Here are the Basic Concepts for you to start using Box2D.
A 2D geometrical object, such as a circle or polygon
A chunk of matter that is so strong that the distance between any two bits of matter on the chunk is
constant. They are hard like a diamond. In the following discussion we use body interchangeably with
A fixture binds a shape to a body and adds material properties such as density, friction, and restitution.
A constraint is a physical connection that removes degrees of freedom from bodies. In 2D a body has 3
degrees of freedom (two translation coordinates and one rotation coordinate). If we take a body and pin
it to the wall (like a pendulum) we have constrained the body to the wall. At this point the body can only
rotate about the pin, so the constraint has removed 2 degrees of freedom.
A special constraint designed to prevent penetration of rigid bodies and to simulate friction and
restitution. You do not create contact constraints; they are created automatically by Box2D.
This is a constraint used to hold two or more bodies together. Box2D supports several Joint types:
revolute, prismatic, distance, and more. Some joints may have limits and motors.
A joint limit restricts the range of motion of a joint. For example, the human elbow only allows a certain
range of angles.
A joint motor drives the motion of the connected bodies according to the joint’s degrees of freedom. For
example, you can use a motor to drive the rotation of an elbow.
A physics world is a collection of bodies, fixtures, and constraints that interact together. Box2D supports
the creation of multiple worlds, but this is usually not necessary or desirable.
The physics world has a solver that is used to advance time and to resolve contact and joint constraints.
The Box2D solver is a high performance iterative solver that operates in order N time, where N is the
number of constraints.
The solver advances bodies in time using discrete time steps. Without intervention this can lead to