/PhysicsEngines/Bullet/BulletBody.cs

using System.Collections.Generic;

using BulletXNA;

using BulletXNA.BulletCollision;

using BulletXNA.BulletDynamics;

using Delta.PhysicsEngines.Enums;

using Delta.Rendering.Models;

using Delta.Utilities.Datatypes;

using Delta.Utilities.Helpers;

using BulletVector3 = Microsoft.Xna.Framework.Vector3;

using BulletMatrix = Microsoft.Xna.Framework.Matrix;



namespace Delta.PhysicsEngines.Bullet

{

	/// <summary>

	/// Bullet implementation of PhysicsBody.

	/// </summary>

	internal class BulletBody : PhysicsBody

	{

		#region Position (Public)

		public override Vector Position

		{

			get

			{

				DefaultMotionState myMotionState =

					(DefaultMotionState)bulletBody.GetMotionState();



				BulletMatrix bulletMatrix;

				myMotionState.GetWorldTransform(out bulletMatrix);



				return BulletDatatypesMapping.Convert(

					bulletMatrix.Translation);

			}

			set

			{

				// Do we need to multiply here?

				var transMatrix = BulletMatrix.CreateTranslation(

					BulletDatatypesMapping.Convert(value));



				DefaultMotionState motionState =

					(DefaultMotionState)bulletBody.GetMotionState();



				motionState.m_graphicsWorldTrans = transMatrix;

			}

		}

		#endregion



		#region Position2D (Public)

		public override Point Position2D

		{

			get

			{

				return Position.ToPoint();

			}

			set

			{

				// This is 3D physics engine, so do nothing by default.

			}

		}

		#endregion



		#region LinearVelocity (Public)

		public override Vector LinearVelocity

		{

			get

			{

				BulletVector3 bulletVec = bulletBody.GetLinearVelocity();

				return BulletDatatypesMapping.Convert(bulletVec);

			}

			set

			{

				bulletBody.SetLinearVelocity(

					BulletDatatypesMapping.Convert(value));

			}

		}

		#endregion



		#region AngularVelocity (Public)

		public override Vector AngularVelocity

		{

			get

			{

				BulletVector3 bulletVec = bulletBody.GetAngularVelocity();

				return BulletDatatypesMapping.Convert(bulletVec);

			}

			set

			{

				bulletBody.SetAngularVelocity(

					BulletDatatypesMapping.Convert(value));

			}

		}

		#endregion



		#region AngularVelocity2D (Public)

		public override float AngularVelocity2D

		{

			get

			{

				return AngularVelocity.X;

			}

			set

			{

				// This is 3D physics engine, so do nothing by default.

			}

		}

		#endregion



		#region Mass (Public)

		public override float Mass

		{

			get

			{

				return base.Mass;

			}

			set

			{

				bulletBody.SetMassProps(value, initialInhertia);

			}

		}

		#endregion



		#region Restitution (Public)

		public override float Restitution

		{

			get

			{

				return base.Restitution;

			}

			set

			{

				bulletBody.SetRestitution(value);

				base.Restitution = value;

			}

		}

		#endregion



		#region BoundingBox (Public)

		public override BoundingBox BoundingBox

		{

			get

			{

				// Probably this will be removed in future

				BulletVector3 min, max;

				bulletBody.GetAabb(out min, out max);

				return new BoundingBox(

					BulletDatatypesMapping.Convert(min),

					BulletDatatypesMapping.Convert(max));

			}

		}

		#endregion



		#region Internal



		#region bulletBody (Internal)

		internal RigidBody bulletBody;

		#endregion



		#endregion



		#region Private



		#region bulletPhysics (Private)

		private BulletPhysics bulletPhysics;

		#endregion



		#region bulletShape (Private)

		private CollisionShape bulletShape;

		#endregion



		#region oldMass (Private)

		private float oldMass;

		#endregion



		#region initialInhertia (Private)

		private BulletVector3 initialInhertia;

		#endregion



		#endregion



		#region Constructors

		/// <summary>

		/// Creates a new instance of <see cref="BulletBody"/>

		/// </summary>

		/// <param name="bulletPhysics">The physics manager.</param>

		/// <param name="shape">The shape.</param>

		public BulletBody(BulletPhysics bulletPhysics,

			PhysicsShape shape, Vector initialPosition)

			: base(false, shape, initialPosition)

		{

			this.bulletPhysics = bulletPhysics;



			// First create shape.

			CreateShape();



			// Now create Bullet body.

			CreateBody();



			// Now add it to world simulation

			bulletPhysics.bulletWorld.AddRigidBody(bulletBody);

		}



		/// <summary>

		///  Internal constructor for creating GroundBody.

		/// </summary>

		/// <param name="bulletPhysics">The BulletPhysics implementation.</param>

		/// <param name="bulletBody">The already create Bullet body.</param>

		/// <param name="bulletShape">The already create Bullet CollisionShape.</param>

		internal BulletBody(BulletPhysics bulletPhysics,

			RigidBody bulletBody, CollisionShape bulletShape)

			: base(false, null, Vector.Zero)

		{

			this.bulletPhysics = bulletPhysics;

			this.bulletBody = bulletBody;

			this.bulletShape = bulletShape;

		}

		#endregion



		#region ApplyForce (Public)

		public override void ApplyForce(Vector force)

		{

			BulletVector3 bulletVec = BulletDatatypesMapping.Convert(force);

			BulletVector3 relPos = BulletVector3.Zero;

			bulletBody.ApplyForce(ref bulletVec, ref relPos);

		}



		public override void ApplyForce(Vector force, Vector position)

		{

			BulletVector3 bulletVec = BulletDatatypesMapping.Convert(force);

			BulletVector3 relPos = BulletDatatypesMapping.Convert(position);

			bulletBody.ApplyForce(ref bulletVec, ref relPos);

		}

		#endregion



		#region ApplyTorque (Public)

		public override void ApplyTorque(Vector torque)

		{

			BulletVector3 bulletTorque = BulletDatatypesMapping.Convert(torque);

			bulletBody.ApplyTorque(ref bulletTorque);

		}

		#endregion



		#region ApplyLinearImpulse (Public)

		public override void ApplyLinearImpulse(Vector impulse)

		{

			BulletVector3 bulletVec = BulletDatatypesMapping.Convert(impulse);

			BulletVector3 relPos = BulletVector3.Zero;

			bulletBody.ApplyImpulse(ref bulletVec, ref relPos);

		}



		public override void ApplyLinearImpulse(Vector impulse, Vector position)

		{

			BulletVector3 bulletVec = BulletDatatypesMapping.Convert(impulse);

			BulletVector3 relPos = BulletDatatypesMapping.Convert(position);

			bulletBody.ApplyImpulse(ref bulletVec, ref relPos);

		}

		#endregion



		#region ApplyAngularImpulse (Public)

		public override void ApplyAngularImpulse(Vector impulse)

		{

			BulletVector3 bulletVec = BulletDatatypesMapping.Convert(impulse);

			BulletVector3 relPos = BulletVector3.Zero;

			bulletBody.ApplyImpulse(ref bulletVec, ref relPos);

		}

		#endregion



		#region Methods (Private)



		#region CreateShape

		/// <summary>

		/// Creates Bullet CollsionShape from properties.

		/// </summary>

		private void CreateShape()

		{

			//http://www.bulletphysics.org/mediawiki-1.5.8/index.php/Collision_Shapes

			Dictionary<PhysicsShape.PropertyType, object> properties =

				base.Shape.Properties;

			switch (Shape.ShapeType)

			{

				case ShapeType.Sphere:

					bulletShape = new SphereShape(

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Radius));

					break;

				case ShapeType.Box:

					Vector size =

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, Vector>(

							properties, PhysicsShape.PropertyType.Size);

					BulletVector3 bulletVector =

						BulletDatatypesMapping.Convert(size / 2.0f);

					bulletShape = new BoxShape(

						ref bulletVector

						);

					break;

				case ShapeType.Capsule:

					bulletShape = new CapsuleShape(

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Radius),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Depth));

					break;

				case ShapeType.Cone:

					bulletShape = new ConeShape(

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Radius),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Height));

					break;

				case ShapeType.Cylinder:

					BulletVector3 bulletVec = new BulletVector3(

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Height),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Radius),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, float>(

							properties, PhysicsShape.PropertyType.Height));

					bulletShape = new CylinderShape(bulletVec);

					break;



				case ShapeType.Triangle:

					bulletShape = Helpers.CreateFrom(

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, Mesh>(

							properties, PhysicsShape.PropertyType.Mesh),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, Matrix>(

							properties, PhysicsShape.PropertyType.LocalSpaceMatrix),

						ArrayHelper.SafeGet<PhysicsShape.PropertyType, bool>(

							properties, PhysicsShape.PropertyType.InvertTriangles));

					break;

			}



			// Store our body to collision user data.

			bulletShape.SetUserPointer(this);

		}

		#endregion



		#region CreateBody

		/// <summary>

		/// Creates Bullet body just after we create CollisionShape.

		/// </summary>

		private void CreateBody()

		{

			bool isDynamic = Mass != 0.0f;



			initialInhertia = BulletVector3.Zero;

			if (isDynamic)

			{

				bulletShape.CalculateLocalInertia(Mass, out initialInhertia);

			}



			BulletMatrix initialTransform =

				BulletMatrix.CreateTranslation(

					base.InitialPosition.X, base.InitialPosition.Y, base.InitialPosition.Z

					);

			// Using motionstate is recommended, it provides interpolation 

			// capabilities, and only synchronizes 'active' objects

			DefaultMotionState initialMotionState = new DefaultMotionState(

				initialTransform, BulletMatrix.Identity);



			RigidBodyConstructionInfo rbInfo = new RigidBodyConstructionInfo(

				Mass, initialMotionState, bulletShape, initialInhertia);

			rbInfo.m_restitution = base.restitution;



			bulletBody = new RigidBody(rbInfo);

			// Store our body to collision user data.

			bulletBody.SetUserPointer(this);



			// Apply mass and resitution too.

			bulletBody.SetMassProps(base.Mass, initialInhertia);

		}

		#endregion



		#region SetIsStatic

		protected override void SetIsStatic(bool value)

		{

			if (value)

			{

				oldMass = base.Mass;

				// By setting mass = 0.0 body is static in bullet

				bulletBody.SetMassProps(0.0f, BulletVector3.Zero);

			}

			else

			{

				bulletBody.SetMassProps(oldMass, ref initialInhertia);

			}

		}

		#endregion



		#region SetIsActive

		protected override void SetIsActive(bool value)

		{

			bulletBody.SetActivationState(value

			                              	? ActivationState.ACTIVE_TAG

			                              	: ActivationState.DISABLE_SIMULATION);

		}

		#endregion



		#region SetFriction

		protected override void SetFriction(float value)

		{

			bulletBody.SetFriction(value);

		}

		#endregion



		#endregion

	}

}