/PhysicsEngines/Farseer/FarseerJoint.cs

  1using Delta.Utilities.Datatypes;
  2using Delta.Utilities.Helpers;
  3using FarseerPhysics.Dynamics.Joints;
  4using FarseerPhysics.Factories;
  5using Microsoft.Xna.Framework;
  6using JointType = Delta.PhysicsEngines.Enums.JointType;
  7
  8namespace Delta.PhysicsEngines.Farseer
  9{
 10	/// <summary>
 11	/// Farseer joint implementation.
 12	/// </summary>
 13	internal class FarseerJoint : PhysicsJoint
 14	{
 15		#region Joint (Public)
 16		/// <summary>
 17		/// Gets farseer joint object.
 18		/// </summary>
 19		public Joint Joint
 20		{
 21			get;
 22			private set;
 23		}
 24		#endregion
 25
 26		#region Private
 27
 28		#region physicsManager (Private)
 29		private readonly FarseerPhysics physicsManager;
 30		#endregion
 31
 32		#endregion
 33
 34		#region Constructors
 35		/// <summary>
 36		/// Creates a new instance of the <see cref="FarseerJoint"/> class.
 37		/// </summary>
 38		/// <param name="physicsManager">The physics manager.</param>
 39		/// <param name="jointType">Type of the joint.</param>
 40		/// <param name="bodyA">The body A.</param>
 41		/// <param name="bodyB">The body B.</param>
 42		/// <param name="args">The args.</param>
 43		public FarseerJoint(
 44			FarseerPhysics physicsManager,
 45			JointType jointType,
 46			PhysicsBody bodyA,
 47			PhysicsBody bodyB, object[] args)
 48			: base(jointType, bodyA, bodyB, args)
 49		{
 50			this.physicsManager = physicsManager;
 51
 52			CreateJoint();
 53		}
 54		#endregion
 55
 56		#region Methods (Private)
 57
 58		#region CreateJoint
 59		/// <summary>
 60		/// Create joint from properties.
 61		/// </summary>
 62		private void CreateJoint()
 63		{
 64			var farseerBodyA = (BodyA as FarseerBody).Body;
 65			var farseerBodyB = (BodyB as FarseerBody).Body;
 66
 67			Vector tempVector;
 68			switch (JointType)
 69			{
 70				case JointType.Angle:
 71					AngleJoint angleJoint = JointFactory.CreateAngleJoint(
 72						physicsManager.farseerPhysicsWorld,
 73						farseerBodyA,
 74						farseerBodyB);
 75
 76					angleJoint.MaxImpulse = 3;
 77					angleJoint.TargetAngle =
 78						ArrayHelper.SafeGet<PropertyType, float>(
 79							base.Properties, PropertyType.TargetAngle);
 80
 81					Joint = angleJoint;
 82					break;
 83				case JointType.Prismatic:
 84					PrismaticJoint prismaticJoint = JointFactory.CreatePrismaticJoint(
 85						farseerBodyA, farseerBodyB, Vector2.Zero, Vector2.Zero);
 86					Joint = prismaticJoint;
 87					break;
 88
 89				case JointType.PointPointDistance:
 90					tempVector = ArrayHelper.SafeGet<PropertyType, Vector>(
 91						Properties, PropertyType.Anchor1);
 92					Vector2 anchor1 = FarseerDatatypesMapping.Convert(ref tempVector);
 93
 94					tempVector = ArrayHelper.SafeGet<PropertyType, Vector>(
 95						Properties, PropertyType.Anchor2);
 96					Vector2 anchor2 = FarseerDatatypesMapping.Convert(ref tempVector);
 97
 98					var distanceJoint = JointFactory.CreateDistanceJoint(
 99						physicsManager.farseerPhysicsWorld, farseerBodyA,
100						farseerBodyB, anchor1, anchor2);
101
102					// Calculate length
103					var d = distanceJoint.BodyB.GetWorldPoint(distanceJoint.LocalAnchorB) -
104					        distanceJoint.BodyA.GetWorldPoint(distanceJoint.LocalAnchorA);
105					distanceJoint.Length = d.Length();
106					break;
107			}
108
109			if (Joint != null)
110			{
111				Joint.CollideConnected = true;
112			}
113		}
114		#endregion
115
116		#endregion
117	}
118}