Box2DX.Dynamics.Body.SetMass C# (CSharp) Method

		public void SetMass(MassData massData)
		{
			Box2DXDebug.Assert(_world._lock == false);
			if (_world._lock == true)
			{
				return;
			}

			_invMass = 0.0f;
			_I = 0.0f;
			_invI = 0.0f;

			_mass = massData.Mass;

			if (_mass > 0.0f)
			{
				_invMass = 1.0f / _mass;
			}

			_I = massData.I;

			if (_I > 0.0f && (_flags & BodyFlags.FixedRotation) == 0)
			{
				_invI = 1.0f / _I;
			}

			// Move center of mass.
			_sweep.LocalCenter = massData.Center;
			_sweep.C0 = _sweep.C = _xf.TransformPoint(_sweep.LocalCenter);

			BodyType oldType = _type;
			if (_invMass == 0.0f && _invI == 0.0f)
			{
				_type = BodyType.Static;
			}
			else
			{
				_type = BodyType.Dynamic;
			}

			// If the body type changed, we need to refilter the broad-phase proxies.
			if (oldType != _type)
			{
				for (Fixture f = _fixtureList; f != null; f = f.Next)
				{
					f.RefilterProxy(_world._broadPhase, _xf);
				}
			}
		}

        private void InitPhysics(BattleArena arena)
        {
            // Define the dynamic body. We set its position and call the body factory.
            BodyDef bodyDef = new BodyDef();
            bodyDef.Position.Set(0.0f, 4.0f);
            body = arena.world.CreateBody(bodyDef);

            // Define another box shape for our dynamic body.
            PolygonDef shapeDef = new PolygonDef();
            shapeDef.SetAsBox(Pokemon.Width / 2, Pokemon.Height / 2);

            // Set the box density to be non-zero, so it will be dynamic.
            shapeDef.Density = 1.0f;

            // Override the default friction.
            //shapeDef.Friction = 2f;

            // Add the shape to the body.
            Fixture fix = body.CreateFixture(shapeDef);
            fix.Density = 1;
            fix.Friction = 0.3f;
            fix.Restitution = 0.1f;
            fix.UserData = this;
            fix.Filter.GroupIndex = this.ID;
            fix.Filter.CategoryBits = 0x0002;
            if (Pokemon.Types.Contains(PokemonType.Ghost)){
                fix.Filter.MaskBits = 0xFFFF - 0x0002;
            } else {
                fix.Filter.MaskBits = 0xFFFF;
            }

            // Now tell the dynamic body to compute it's mass properties base
            // on its shape.
            var mass = body.GetMassData();
            mass.Mass = Pokemon.Weight;
            body.SetMass(mass);

            body.SetFixedRotation(true);
        }