FarseerPhysics.Dynamics.Contacts.Contact.update C# (CSharp) Method

		internal void update( ContactManager contactManager )
		{
			var bodyA = fixtureA.body;
			var bodyB = fixtureB.body;

			if( fixtureA == null || fixtureB == null )
				return;

			var oldManifold = manifold;

			// Re-enable this contact.
			enabled = true;

			bool touching;
			var wasTouching = isTouching;
			var sensor = fixtureA.isSensor || fixtureB.isSensor;

			// Is this contact a sensor?
			if( sensor )
			{
				var shapeA = fixtureA.shape;
				var shapeB = fixtureB.shape;
				touching = Collision.Collision.testOverlap( shapeA, childIndexA, shapeB, childIndexB, ref bodyA._xf, ref bodyB._xf );

				// Sensors don't generate manifolds.
				manifold.pointCount = 0;
			}
			else
			{
				evaluate( ref manifold, ref bodyA._xf, ref bodyB._xf );
				touching = manifold.pointCount > 0;

				// Match old contact ids to new contact ids and copy the
				// stored impulses to warm start the solver.
				for( int i = 0; i < manifold.pointCount; ++i )
				{
					var mp2 = manifold.points[i];
					mp2.normalImpulse = 0.0f;
					mp2.tangentImpulse = 0.0f;
					var id2 = mp2.id;

					for( int j = 0; j < oldManifold.pointCount; ++j )
					{
						var mp1 = oldManifold.points[j];

						if( mp1.id.key == id2.key )
						{
							mp2.normalImpulse = mp1.normalImpulse;
							mp2.tangentImpulse = mp1.tangentImpulse;
							break;
						}
					}

					manifold.points[i] = mp2;
				}

				if( touching != wasTouching )
				{
					bodyA.isAwake = true;
					bodyB.isAwake = true;
				}
			}

			isTouching = touching;
			if( wasTouching == false )
			{
				if( touching )
				{
					if( Settings.allCollisionCallbacksAgree )
					{
						bool enabledA = true, enabledB = true;

						// Report the collision to both participants. Track which ones returned true so we can
						// later call OnSeparation if the contact is disabled for a different reason.
						if( fixtureA.onCollision != null )
							foreach( OnCollisionEventHandler handler in fixtureA.onCollision.GetInvocationList() )
								enabledA = handler( fixtureA, fixtureB, this ) && enabledA;

						// Reverse the order of the reported fixtures. The first fixture is always the one that the
						// user subscribed to.
						if( fixtureB.onCollision != null )
							foreach( OnCollisionEventHandler handler in fixtureB.onCollision.GetInvocationList() )
								enabledB = handler( fixtureB, fixtureA, this ) && enabledB;

						enabled = enabledA && enabledB;

						// BeginContact can also return false and disable the contact
						if( enabledA && enabledB && contactManager.onBeginContact != null )
							enabled = contactManager.onBeginContact( this );
					}
					else
					{
						// Report the collision to both participants:
						if( fixtureA.onCollision != null )
							foreach( OnCollisionEventHandler handler in fixtureA.onCollision.GetInvocationList() )
								enabled = handler( fixtureA, fixtureB, this );

						//Reverse the order of the reported fixtures. The first fixture is always the one that the
						//user subscribed to.
						if( fixtureB.onCollision != null )
							foreach( OnCollisionEventHandler handler in fixtureB.onCollision.GetInvocationList() )
								enabled = handler( fixtureB, fixtureA, this );

						//BeginContact can also return false and disable the contact
						if( contactManager.onBeginContact != null )
							enabled = contactManager.onBeginContact( this );
					}

					// If the user disabled the contact (needed to exclude it in TOI solver) at any point by
					// any of the callbacks, we need to mark it as not touching and call any separation
					// callbacks for fixtures that didn't explicitly disable the collision.
					if( !enabled )
						isTouching = false;
				}
			}
			else
			{
				if( touching == false )
				{
					// Report the separation to both participants:
					if( fixtureA != null && fixtureA.onSeparation != null )
						fixtureA.onSeparation( fixtureA, fixtureB );

					//Reverse the order of the reported fixtures. The first fixture is always the one that the
					//user subscribed to.
					if( fixtureB != null && fixtureB.onSeparation != null )
						fixtureB.onSeparation( fixtureB, fixtureA );

					if( contactManager.onEndContact != null )
						contactManager.onEndContact( this );
				}
			}

			if( sensor )
				return;

			if( contactManager.onPreSolve != null )
				contactManager.onPreSolve( this, ref oldManifold );
		}