RigidBody
*********

Intro
=====

A **Rigidbody** in Unity is a component that enables a GameObject to react to physics, like gravity and collisions.
It allows movement through forces making the object behave more realistically in the game world. 

Here are some typical configurations using a RigidBody:

.. hint:: 

		
	* Blocking + Moving
		
		* Object moves and responds to gravity or impulses, can collide and bounce with other elements
		* Useful for: moving car, falling domino, basket-ball 
		* Set: **Collider + RigidBody** 	
		* Function: void OnCollisionEnter(Collision collision)
		

	* Blocking + Immobile
	
		* Object doesn't move, but other objects can bump into it
		* Useful for: walls, floor
		* Set: **Collider only**
		* Function: None

		

		
.. warning:: Beware, when the trigger of the collider is activated, this implicitly disables the rigidbody of the gameobject.
 
 
.. warning:: In previous project, we have moved objects using the translate or rotate function. 
	
Exercise
========

Basic setup
-----------

We begin our study by adding a RigidBody to the sphere.

	* Create a cube and and assign it a color
	
		* Scale the cube to create a ground

	* Select the sphere
	
		* In the Inspector, click on the button *Add Component*
	
		* Select RigidBody
		
		* In the RigidBody section, check: **Use Gravity**
		
		.. image:: usegravity.png
			:scale: 50%
		
		.. image:: fall.png
			:scale: 35%
			 
	* If you want the camera to shoot the same view as the scene view
	
		* In the Hierarchy, select the camera
		* Right click and select Align With View
			
	* Enter Play mode
	
		.. image:: fall.gif
			:scale: 40%

What happened?

	* The sphere has a *Rigidbody*, moreover it is affected by gravity so it falls
	* The ground don't have a *Rigidbody*, it's a static object, it cant move
	* Both the sphere and the ground have a Collider, allowing them to come into contact, which stops the sphere's fall
	
Simulation
----------

We add some new elements to the scene; try to reproduce the scene below.

Some hints:

	* Analyze which object has a RigidBody: is the object moving or not?
	* Detect which object is affected by gravity: it is falling or not ?
	* Enable all options correctly 
	
	.. image:: bascule.png
		:scale: 48%
		
	.. image:: vidbascule.gif
		:scale: 60%