physijs_worker.js

'use strict';
var
	transferableMessage = self.webkitPostMessage || self.postMessage,

	// enum
	MESSAGE_TYPES = {
		WORLDREPORT: 0,
		COLLISIONREPORT: 1,
		VEHICLEREPORT: 2,
		CONSTRAINTREPORT: 3
	},

	// temp variables
	_object,
	_vector,
	_transform,

	// functions
	public_functions = {},
	getShapeFromCache,
	setShapeCache,
	createShape,
	reportWorld,
	reportVehicles,
	reportCollisions,
	reportConstraints,

	// world variables
	fixedTimeStep, // used when calling stepSimulation
	rateLimit, // sets whether or not to sync the simulation rate with fixedTimeStep
	last_simulation_time,
	last_simulation_duration = 0,
	world,
	transform,
	_vec3_1,
	_vec3_2,
	_vec3_3,
	_quat,
	// private cache
	_objects = {},
	_vehicles = {},
	_constraints = {},
	_materials = {},
	_objects_ammo = {},
	_num_objects = 0,
	_num_wheels = 0,
	_num_constraints = 0,
	_object_shapes = {},

	// The following objects are to track objects that ammo.js doesn't clean
	// up. All are cleaned up when they're corresponding body is destroyed.
	// Unfortunately, it's very difficult to get at these objects from the
	// body, so we have to track them ourselves.
	_motion_states = {},
	// Don't need to worry about it for cached shapes.
    _noncached_shapes = {},
	// A body with a compound shape always has a regular shape as well, so we
	// have track them separately.
    _compound_shapes = {},

	// object reporting
	REPORT_CHUNKSIZE, // report array is increased in increments of this chunk size

	WORLDREPORT_ITEMSIZE = 14, // how many float values each reported item needs
	worldreport,

	COLLISIONREPORT_ITEMSIZE = 5, // one float for each object id, and a Vec3 contact normal
	collisionreport,

	VEHICLEREPORT_ITEMSIZE = 9, // vehicle id, wheel index, 3 for position, 4 for rotation
	vehiclereport,

	CONSTRAINTREPORT_ITEMSIZE = 6, // constraint id, offset object, offset, applied impulse
	constraintreport;

var ab = new ArrayBuffer( 1 );

transferableMessage( ab, [ab] );
var SUPPORT_TRANSFERABLE = ( ab.byteLength === 0 );

getShapeFromCache = function ( cache_key ) {
	if ( _object_shapes[ cache_key ] !== undefined ) {
		return _object_shapes[ cache_key ];
	}
	return null;
};

setShapeCache = function ( cache_key, shape ) {
	_object_shapes[ cache_key ] = shape;
}

createShape = function( description ) {
	var cache_key, shape;

	_transform.setIdentity();
	switch ( description.type ) {
		case 'plane':
			cache_key = 'plane_' + description.normal.x + '_' + description.normal.y + '_' + description.normal.z;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				_vec3_1.setX(description.normal.x);
				_vec3_1.setY(description.normal.y);
				_vec3_1.setZ(description.normal.z);
				shape = new Ammo.btStaticPlaneShape(_vec3_1, 0 );
				setShapeCache( cache_key, shape );
			}
			break;

		case 'box':
			cache_key = 'box_' + description.width + '_' + description.height + '_' + description.depth;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				_vec3_1.setX(description.width / 2);
				_vec3_1.setY(description.height / 2);
				_vec3_1.setZ(description.depth / 2);
				shape = new Ammo.btBoxShape(_vec3_1);
				setShapeCache( cache_key, shape );
			}
			break;

		case 'sphere':
			cache_key = 'sphere_' + description.radius;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				shape = new Ammo.btSphereShape( description.radius );
				setShapeCache( cache_key, shape );
			}
			break;

		case 'cylinder':
			cache_key = 'cylinder_' + description.width + '_' + description.height + '_' + description.depth;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				_vec3_1.setX(description.width / 2);
				_vec3_1.setY(description.height / 2);
				_vec3_1.setZ(description.depth / 2);
				shape = new Ammo.btCylinderShape(_vec3_1);
				setShapeCache( cache_key, shape );
			}
			break;

		case 'capsule':
			cache_key = 'capsule_' + description.radius + '_' + description.height;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				// In Bullet, capsule height excludes the end spheres
				shape = new Ammo.btCapsuleShape( description.radius, description.height - 2 * description.radius );
				setShapeCache( cache_key, shape );
			}
			break;

		case 'cone':
			cache_key = 'cone_' + description.radius + '_' + description.height;
			if ( ( shape = getShapeFromCache( cache_key ) ) === null ) {
				shape = new Ammo.btConeShape( description.radius, description.height );
				setShapeCache( cache_key, shape );
			}
			break;

		case 'concave':
			var i, triangle, triangle_mesh = new Ammo.btTriangleMesh;
			if (!description.triangles.length) return false

			for ( i = 0; i < description.triangles.length; i++ ) {
				triangle = description.triangles[i];

				_vec3_1.setX(triangle[0].x);
				_vec3_1.setY(triangle[0].y);
				_vec3_1.setZ(triangle[0].z);

				_vec3_2.setX(triangle[1].x);
				_vec3_2.setY(triangle[1].y);
				_vec3_2.setZ(triangle[1].z);

				_vec3_3.setX(triangle[2].x);
				_vec3_3.setY(triangle[2].y);
				_vec3_3.setZ(triangle[2].z);

				triangle_mesh.addTriangle(
					_vec3_1,
					_vec3_2,
					_vec3_3,
					true
				);
			}

			shape = new Ammo.btBvhTriangleMeshShape(
				triangle_mesh,
				true,
				true
			);
			_noncached_shapes[description.id] = shape;
			break;

		case 'convex':
			var i, point, shape = new Ammo.btConvexHullShape;
			for ( i = 0; i < description.points.length; i++ ) {
				point = description.points[i];

				_vec3_1.setX(point.x);
				_vec3_1.setY(point.y);
				_vec3_1.setZ(point.z);

				shape.addPoint(_vec3_1);

			}
			_noncached_shapes[description.id] = shape;
			break;

		case 'heightfield':

			var ptr = Ammo.allocate(4 * description.xpts * description.ypts, "float", Ammo.ALLOC_NORMAL);

			for (var f = 0; f < description.points.length; f++) {
				Ammo.setValue(ptr + f,  description.points[f]  , 'float');
			}

			shape = new Ammo.btHeightfieldTerrainShape(
					description.xpts,
					description.ypts,
					ptr,
					1,
					-description.absMaxHeight,
					description.absMaxHeight,
					2,
					0,
					false
				);

			_vec3_1.setX(description.xsize/(description.xpts - 1));
			_vec3_1.setY(description.ysize/(description.ypts - 1));
			_vec3_1.setZ(1);

			shape.setLocalScaling(_vec3_1);
			_noncached_shapes[description.id] = shape;
			break;

		default:
			// Not recognized
			return;
			break;
	}

	return shape;
};

public_functions.init = function( params ) {
	importScripts( params.ammo );

	_transform = new Ammo.btTransform;
	_vec3_1 = new Ammo.btVector3(0,0,0);
	_vec3_2 = new Ammo.btVector3(0,0,0);
	_vec3_3 = new Ammo.btVector3(0,0,0);
	_quat = new Ammo.btQuaternion(0,0,0,0);

	REPORT_CHUNKSIZE = params.reportsize || 50;
	if ( SUPPORT_TRANSFERABLE ) {
		// Transferable messages are supported, take advantage of them with TypedArrays
		worldreport = new Float32Array(2 + REPORT_CHUNKSIZE * WORLDREPORT_ITEMSIZE); // message id + # of objects to report + chunk size * # of values per object
		collisionreport = new Float32Array(2 + REPORT_CHUNKSIZE * COLLISIONREPORT_ITEMSIZE); // message id + # of collisions to report + chunk size * # of values per object
		vehiclereport = new Float32Array(2 + REPORT_CHUNKSIZE * VEHICLEREPORT_ITEMSIZE); // message id + # of vehicles to report + chunk size * # of values per object
		constraintreport = new Float32Array(2 + REPORT_CHUNKSIZE * CONSTRAINTREPORT_ITEMSIZE); // message id + # of constraints to report + chunk size * # of values per object
	} else {
		// Transferable messages are not supported, send data as normal arrays
		worldreport = [];
		collisionreport = [];
		vehiclereport = [];
		constraintreport = [];
	}
	worldreport[0] = MESSAGE_TYPES.WORLDREPORT;
	collisionreport[0] = MESSAGE_TYPES.COLLISIONREPORT;
	vehiclereport[0] = MESSAGE_TYPES.VEHICLEREPORT;
	constraintreport[0] = MESSAGE_TYPES.CONSTRAINTREPORT;

	var collisionConfiguration = new Ammo.btDefaultCollisionConfiguration,
		dispatcher = new Ammo.btCollisionDispatcher( collisionConfiguration ),
		solver = new Ammo.btSequentialImpulseConstraintSolver,
		broadphase;

	if ( !params.broadphase ) params.broadphase = { type: 'dynamic' };
	switch ( params.broadphase.type ) {
		case 'sweepprune':

			_vec3_1.setX(params.broadphase.aabbmin.x);
			_vec3_1.setY(params.broadphase.aabbmin.y);
			_vec3_1.setZ(params.broadphase.aabbmin.z);

			_vec3_2.setX(params.broadphase.aabbmax.x);
			_vec3_2.setY(params.broadphase.aabbmax.y);
			_vec3_2.setZ(params.broadphase.aabbmax.z);

			broadphase = new Ammo.btAxisSweep3(
				_vec3_1,
				_vec3_2
			);

			break;

		case 'dynamic':
		default:
			broadphase = new Ammo.btDbvtBroadphase;
			break;
	}

	world = new Ammo.btDiscreteDynamicsWorld( dispatcher, broadphase, solver, collisionConfiguration );

	fixedTimeStep = params.fixedTimeStep;
	rateLimit = params.rateLimit;

	transferableMessage({ cmd: 'worldReady' });
};

public_functions.registerMaterial = function( description ) {
	_materials[ description.id ] = description;
};

public_functions.unRegisterMaterial = function( description ) {
	delete _materials[ description.id ];
};

public_functions.setFixedTimeStep = function( description ) {
	fixedTimeStep = description;
};

public_functions.setGravity = function( description ) {
	_vec3_1.setX(description.x);
	_vec3_1.setY(description.y);
	_vec3_1.setZ(description.z);
	world.setGravity(_vec3_1);
};

public_functions.addObject = function( description ) {

	var i,
	localInertia, shape, motionState, rbInfo, body;

shape = createShape( description );
if (!shape) return
// If there are children then this is a compound shape
if ( description.children ) {
	var compound_shape = new Ammo.btCompoundShape, _child;
	compound_shape.addChildShape( _transform, shape );

	for ( i = 0; i < description.children.length; i++ ) {
		_child = description.children[i];

		var trans = new Ammo.btTransform;
		trans.setIdentity();

		_vec3_1.setX(_child.position_offset.x);
		_vec3_1.setY(_child.position_offset.y);
		_vec3_1.setZ(_child.position_offset.z);
		trans.setOrigin(_vec3_1);

		_quat.setX(_child.rotation.x);
		_quat.setY(_child.rotation.y);
		_quat.setZ(_child.rotation.z);
		_quat.setW(_child.rotation.w);
		trans.setRotation(_quat);

		shape = createShape( description.children[i] );
		compound_shape.addChildShape( trans, shape );
		Ammo.destroy(trans);
	}

	shape = compound_shape;
    _compound_shapes[ description.id ] = shape;
	}
	_vec3_1.setX(0);
	_vec3_1.setY(0);
	_vec3_1.setZ(0);
	shape.calculateLocalInertia( description.mass, _vec3_1 );

	_transform.setIdentity();

	_vec3_2.setX(description.position.x);
	_vec3_2.setY(description.position.y);
	_vec3_2.setZ(description.position.z);
	_transform.setOrigin(_vec3_2);

	_quat.setX(description.rotation.x);
	_quat.setY(description.rotation.y);
	_quat.setZ(description.rotation.z);
	_quat.setW(description.rotation.w);
	_transform.setRotation(_quat);

	motionState = new Ammo.btDefaultMotionState( _transform ); // #TODO: btDefaultMotionState supports center of mass offset as second argument - implement
	rbInfo = new Ammo.btRigidBodyConstructionInfo( description.mass, motionState, shape, _vec3_1 );

	if ( description.materialId !== undefined ) {
		rbInfo.set_m_friction( _materials[ description.materialId ].friction );
		rbInfo.set_m_restitution( _materials[ description.materialId ].restitution );
	}

	body = new Ammo.btRigidBody( rbInfo );
	Ammo.destroy(rbInfo);

	if ( typeof description.collision_flags !== 'undefined' ) {
		body.setCollisionFlags( description.collision_flags );
	}

	world.addRigidBody( body );

	body.id = description.id;
	_objects[ body.id ] = body;
	_motion_states[ body.id ] = motionState;

	var ptr = body.a != undefined ? body.a : body.ptr;
	_objects_ammo[ptr] = body.id;
	_num_objects++;

	transferableMessage({ cmd: 'objectReady', params: body.id });
};

public_functions.addVehicle = function( description ) {
	var vehicle_tuning = new Ammo.btVehicleTuning(),
		vehicle;

	vehicle_tuning.set_m_suspensionStiffness( description.suspension_stiffness );
	vehicle_tuning.set_m_suspensionCompression( description.suspension_compression );
	vehicle_tuning.set_m_suspensionDamping( description.suspension_damping );
	vehicle_tuning.set_m_maxSuspensionTravelCm( description.max_suspension_travel );
	vehicle_tuning.set_m_maxSuspensionForce( description.max_suspension_force );

	vehicle = new Ammo.btRaycastVehicle( vehicle_tuning, _objects[ description.rigidBody ], new Ammo.btDefaultVehicleRaycaster( world ) );
	vehicle.tuning = vehicle_tuning;

	_objects[ description.rigidBody ].setActivationState( 4 );
	vehicle.setCoordinateSystem( 0, 1, 2 );

	world.addVehicle( vehicle );
	_vehicles[ description.id ] = vehicle;
};
public_functions.removeVehicle = function( description ) {
	delete _vehicles[ description.id ];
};

public_functions.addWheel = function( description ) {
	if ( _vehicles[description.id] !== undefined ) {
		var tuning = _vehicles[description.id].tuning;
		if ( description.tuning !== undefined ) {
			tuning = new Ammo.btVehicleTuning();
			tuning.set_m_suspensionStiffness( description.tuning.suspension_stiffness );
			tuning.set_m_suspensionCompression( description.tuning.suspension_compression );
			tuning.set_m_suspensionDamping( description.tuning.suspension_damping );
			tuning.set_m_maxSuspensionTravelCm( description.tuning.max_suspension_travel );
			tuning.set_m_maxSuspensionForce( description.tuning.max_suspension_force );
		}

		_vec3_1.setX(description.connection_point.x);
		_vec3_1.setY(description.connection_point.y);
		_vec3_1.setZ(description.connection_point.z);

		_vec3_2.setX(description.wheel_direction.x);
		_vec3_2.setY(description.wheel_direction.y);
		_vec3_2.setZ(description.wheel_direction.z);

		_vec3_3.setX(description.wheel_axle.x);
		_vec3_3.setY(description.wheel_axle.y);
		_vec3_3.setZ(description.wheel_axle.z);

		_vehicles[description.id].addWheel(
			_vec3_1,
			_vec3_2,
			_vec3_3,
			description.suspension_rest_length,
			description.wheel_radius,
			tuning,
			description.is_front_wheel
		);
	}

	_num_wheels++;

	if ( SUPPORT_TRANSFERABLE ) {
		vehiclereport = new Float32Array(1 + _num_wheels * VEHICLEREPORT_ITEMSIZE); // message id & ( # of objects to report * # of values per object )
		vehiclereport[0] = MESSAGE_TYPES.VEHICLEREPORT;
	} else {
		vehiclereport = [ MESSAGE_TYPES.VEHICLEREPORT ];
	}
};

public_functions.setSteering = function( details ) {
	if ( _vehicles[details.id] !== undefined ) {
		_vehicles[details.id].setSteeringValue( details.steering, details.wheel );
	}
};
public_functions.setBrake = function( details ) {
	if ( _vehicles[details.id] !== undefined ) {
		_vehicles[details.id].setBrake( details.brake, details.wheel );
	}
};
public_functions.applyEngineForce = function( details ) {
	if ( _vehicles[details.id] !== undefined ) {
		_vehicles[details.id].applyEngineForce( details.force, details.wheel );
	}
};

public_functions.removeObject = function( details ) {
	world.removeRigidBody( _objects[details.id] );
	Ammo.destroy(_objects[details.id]);
	Ammo.destroy(_motion_states[details.id]);
    if (_compound_shapes[details.id]) Ammo.destroy(_compound_shapes[details.id]);
	if (_noncached_shapes[details.id]) Ammo.destroy(_noncached_shapes[details.id]);
	var ptr = _objects[details.id].a != undefined ? _objects[details.id].a : _objects[details.id].ptr;
	delete _objects_ammo[ptr];
	delete _objects[details.id];
	delete _motion_states[details.id];
    if (_compound_shapes[details.id]) delete _compound_shapes[details.id];
	if (_noncached_shapes[details.id]) delete _noncached_shapes[details.id];
	_num_objects--;
};

public_functions.updateTransform = function( details ) {
	_object = _objects[details.id];
	_object.getMotionState().getWorldTransform( _transform );

	if ( details.pos ) {
		_vec3_1.setX(details.pos.x);
		_vec3_1.setY(details.pos.y);
		_vec3_1.setZ(details.pos.z);
		_transform.setOrigin(_vec3_1);
	}

	if ( details.quat ) {
		_quat.setX(details.quat.x);
		_quat.setY(details.quat.y);
		_quat.setZ(details.quat.z);
		_quat.setW(details.quat.w);
		_transform.setRotation(_quat);
	}

	_object.setWorldTransform( _transform );
	_object.activate();
};

public_functions.updateMass = function( details ) {
	// #TODO: changing a static object into dynamic is buggy
	_object = _objects[details.id];

	// Per http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?p=&f=9&t=3663#p13816
	world.removeRigidBody( _object );

	_vec3_1.setX(0);
	_vec3_1.setY(0);
	_vec3_1.setZ(0);

	_object.setMassProps( details.mass, _vec3_1 );
	world.addRigidBody( _object );
	_object.activate();
};

public_functions.applyCentralImpulse = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].applyCentralImpulse(_vec3_1);
	_objects[details.id].activate();
};

public_functions.applyImpulse = function ( details ) {

	_vec3_1.setX(details.impulse_x);
	_vec3_1.setY(details.impulse_y);
	_vec3_1.setZ(details.impulse_z);

	_vec3_2.setX(details.x);
	_vec3_2.setY(details.y);
	_vec3_2.setZ(details.z);

	_objects[details.id].applyImpulse(
		_vec3_1,
		_vec3_2
	);
	_objects[details.id].activate();
};

public_functions.applyTorque = function ( details ) {

	_vec3_1.setX(details.torque_x);
	_vec3_1.setY(details.torque_y);
	_vec3_1.setZ(details.torque_z);

	_objects[details.id].applyTorque(
		_vec3_1
	);
	_objects[details.id].activate();
};

public_functions.applyCentralForce = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].applyCentralForce(_vec3_1);
	_objects[details.id].activate();
};

public_functions.applyForce = function ( details ) {

	_vec3_1.setX(details.force_x);
	_vec3_1.setY(details.force_y);
	_vec3_1.setZ(details.force_z);

	_vec3_2.setX(details.x);
	_vec3_2.setY(details.y);
	_vec3_2.setZ(details.z);

	_objects[details.id].applyForce(
		_vec3_1,
		_vec3_2
	);
	_objects[details.id].activate();
};

public_functions.onSimulationResume = function( params ) {
	last_simulation_time = Date.now();
};

public_functions.setAngularVelocity = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].setAngularVelocity(
		_vec3_1
	);
	_objects[details.id].activate();
};

public_functions.setLinearVelocity = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].setLinearVelocity(
		_vec3_1
	);
	_objects[details.id].activate();
};

public_functions.setAngularFactor = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].setAngularFactor(
			_vec3_1
	);
};

public_functions.setLinearFactor = function ( details ) {

	_vec3_1.setX(details.x);
	_vec3_1.setY(details.y);
	_vec3_1.setZ(details.z);

	_objects[details.id].setLinearFactor(
		_vec3_1
	);
};

public_functions.setDamping = function ( details ) {
	_objects[details.id].setDamping( details.linear, details.angular );
};

public_functions.setCcdMotionThreshold = function ( details ) {
	_objects[details.id].setCcdMotionThreshold( details.threshold );
};

public_functions.setCcdSweptSphereRadius = function ( details ) {
	_objects[details.id].setCcdSweptSphereRadius( details.radius );
};

public_functions.addConstraint = function ( details ) {
	var constraint;

	switch ( details.type ) {

		case 'point':
			if ( details.objectb === undefined ) {

				_vec3_1.setX(details.positiona.x);
				_vec3_1.setY(details.positiona.y);
				_vec3_1.setZ(details.positiona.z);

				constraint = new Ammo.btPoint2PointConstraint(
					_objects[ details.objecta ],
					_vec3_1
				);
			} else {

				_vec3_1.setX(details.positiona.x);
				_vec3_1.setY(details.positiona.y);
				_vec3_1.setZ(details.positiona.z);

				_vec3_2.setX(details.positionb.x);
				_vec3_2.setY(details.positionb.y);
				_vec3_2.setZ(details.positionb.z);

				constraint = new Ammo.btPoint2PointConstraint(
					_objects[ details.objecta ],
					_objects[ details.objectb ],
					_vec3_1,
					_vec3_2
				);
			}
			break;

		case 'hinge':
			if ( details.objectb === undefined ) {

				_vec3_1.setX(details.positiona.x);
				_vec3_1.setY(details.positiona.y);
				_vec3_1.setZ(details.positiona.z);

				_vec3_2.setX(details.axis.x);
				_vec3_2.setY(details.axis.y);
				_vec3_2.setZ(details.axis.z);

				constraint = new Ammo.btHingeConstraint(
					_objects[ details.objecta ],
					_vec3_1,
					_vec3_2
				);
			} else {

				_vec3_1.setX(details.positiona.x);
				_vec3_1.setY(details.positiona.y);
				_vec3_1.setZ(details.positiona.z);

				_vec3_2.setX(details.positionb.x);
				_vec3_2.setY(details.positionb.y);
				_vec3_2.setZ(details.positionb.z);

				_vec3_3.setX(details.axis.x);
				_vec3_3.setY(details.axis.y);
				_vec3_3.setZ(details.axis.z);

				constraint = new Ammo.btHingeConstraint(
					_objects[ details.objecta ],
					_objects[ details.objectb ],
					_vec3_1,
					_vec3_2,
					_vec3_3,
					_vec3_3
				);
			}
			break;

		case 'slider':
			var transforma, transformb, rotation;

			transforma = new Ammo.btTransform();

			_vec3_1.setX(details.positiona.x);
			_vec3_1.setY(details.positiona.y);
			_vec3_1.setZ(details.positiona.z);

			transforma.setOrigin(_vec3_1);

			var rotation = transforma.getRotation();
			rotation.setEuler( details.axis.x, details.axis.y, details.axis.z );
			transforma.setRotation( rotation );

			if ( details.objectb ) {
				transformb = new Ammo.btTransform();

				_vec3_2.setX(details.positionb.x);
				_vec3_2.setY(details.positionb.y);
				_vec3_2.setZ(details.positionb.z);

				transformb.setOrigin(_vec3_2);

				rotation = transformb.getRotation();
				rotation.setEuler( details.axis.x, details.axis.y, details.axis.z );
				transformb.setRotation( rotation );

				constraint = new Ammo.btSliderConstraint(
					_objects[ details.objecta ],
					_objects[ details.objectb ],
					transforma,
					transformb,
					true
				);
			} else {
				constraint = new Ammo.btSliderConstraint(
					_objects[ details.objecta ],
					transforma,
					true
				);
			}

			Ammo.destroy(transforma);
			if (transformb != undefined) {
				Ammo.destroy(transformb);
			}
			break;

		case 'conetwist':
			var transforma, transformb;

			transforma = new Ammo.btTransform();
			transforma.setIdentity();

			transformb = new Ammo.btTransform();
			transformb.setIdentity();

			_vec3_1.setX(details.positiona.x);
			_vec3_1.setY(details.positiona.y);
			_vec3_1.setZ(details.positiona.z);

			_vec3_2.setX(details.positionb.x);
			_vec3_2.setY(details.positionb.y);
			_vec3_2.setZ(details.positionb.z);

			transforma.setOrigin(_vec3_1);
			transformb.setOrigin(_vec3_2);

			var rotation = transforma.getRotation();
			rotation.setEulerZYX( -details.axisa.z, -details.axisa.y, -details.axisa.x );
			transforma.setRotation( rotation );

			rotation = transformb.getRotation();
			rotation.setEulerZYX( -details.axisb.z, -details.axisb.y, -details.axisb.x );
			transformb.setRotation( rotation );

			constraint = new Ammo.btConeTwistConstraint(
				_objects[ details.objecta ],
				_objects[ details.objectb ],
				transforma,
				transformb
			);

			constraint.setLimit( Math.PI, 0, Math.PI );

			Ammo.destroy(transforma);
			Ammo.destroy(transformb);

			break;

		case 'dof':
			var transforma, transformb, rotation;

			transforma = new Ammo.btTransform();
			transforma.setIdentity();

			_vec3_1.setX(details.positiona.x);
			_vec3_1.setY(details.positiona.y);
			_vec3_1.setZ(details.positiona.z);

			transforma.setOrigin(_vec3_1 );

			rotation = transforma.getRotation();
			rotation.setEulerZYX( -details.axisa.z, -details.axisa.y, -details.axisa.x );
			transforma.setRotation( rotation );

			if ( details.objectb ) {
				transformb = new Ammo.btTransform();
				transformb.setIdentity();

				_vec3_2.setX(details.positionb.x);
				_vec3_2.setY(details.positionb.y);
				_vec3_2.setZ(details.positionb.z);

				transformb.setOrigin(_vec3_2);

				rotation = transformb.getRotation();
				rotation.setEulerZYX( -details.axisb.z, -details.axisb.y, -details.axisb.x );
				transformb.setRotation( rotation );

				constraint = new Ammo.btGeneric6DofConstraint(
					_objects[ details.objecta ],
					_objects[ details.objectb ],
					transforma,
					transformb
				);
			} else {
				constraint = new Ammo.btGeneric6DofConstraint(
					_objects[ details.objecta ],
					transforma
				);
			}
			Ammo.destroy(transforma);
			if (transformb != undefined) {
				Ammo.destroy(transformb);
			}
			break;

		default:
			return;

	};

	world.addConstraint( constraint );

	constraint.enableFeedback();
	_constraints[ details.id ] = constraint;
	_num_constraints++;

	if ( SUPPORT_TRANSFERABLE ) {
		constraintreport = new Float32Array(1 + _num_constraints * CONSTRAINTREPORT_ITEMSIZE); // message id & ( # of objects to report * # of values per object )
		constraintreport[0] = MESSAGE_TYPES.CONSTRAINTREPORT;
	} else {
		constraintreport = [ MESSAGE_TYPES.CONSTRAINTREPORT ];
	}
};

public_functions.removeConstraint = function( details ) {
	var constraint = _constraints[ details.id ];
	if ( constraint !== undefined ) {
		world.removeConstraint( constraint );
		delete _constraints[ details.id ];
		_num_constraints--;
	}
};

public_functions.constraint_setBreakingImpulseThreshold = function( details ) {
	var constraint = _constraints[ details.id ];
	if ( constraint !== undefind ) {
		constraint.setBreakingImpulseThreshold( details.threshold );
	}
};

public_functions.simulate = function simulate( params ) {
	if ( world ) {
		params = params || {};

		if ( !params.timeStep ) {
			if ( last_simulation_time ) {
				params.timeStep = 0;
				while ( params.timeStep + last_simulation_duration <= fixedTimeStep ) {
					params.timeStep = ( Date.now() - last_simulation_time ) / 1000; // time since last simulation
				}
			} else {
				params.timeStep = fixedTimeStep; // handle first frame
			}
		} else {
			if ( params.timeStep < fixedTimeStep ) {
				params.timeStep = fixedTimeStep;
			}
		}

		params.maxSubSteps = params.maxSubSteps || Math.ceil( params.timeStep / fixedTimeStep ); // If maxSubSteps is not defined, keep the simulation fully up to date

		last_simulation_duration = Date.now();
		world.stepSimulation( params.timeStep, params.maxSubSteps, fixedTimeStep );

		reportVehicles();
		reportCollisions();
		reportConstraints();
		reportWorld();

		last_simulation_duration = ( Date.now() - last_simulation_duration ) / 1000;
		last_simulation_time = Date.now();
	}
};


// Constraint functions
public_functions.hinge_setLimits = function( params ) {
	_constraints[ params.constraint ].setLimit( params.low, params.high, 0, params.bias_factor, params.relaxation_factor );
};
public_functions.hinge_enableAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.enableAngularMotor( true, params.velocity, params.acceleration );
	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.hinge_disableMotor = function( params ) {
	_constraints[ params.constraint ].enableMotor( false );
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};

public_functions.slider_setLimits = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setLowerLinLimit( params.lin_lower || 0 );
	constraint.setUpperLinLimit( params.lin_upper || 0 );

	constraint.setLowerAngLimit( params.ang_lower || 0 );
	constraint.setUpperAngLimit( params.ang_upper || 0 );
};
public_functions.slider_setRestitution = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setSoftnessLimLin( params.linear || 0 );
	constraint.setSoftnessLimAng( params.angular || 0 );
};
public_functions.slider_enableLinearMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setTargetLinMotorVelocity( params.velocity );
	constraint.setMaxLinMotorForce( params.acceleration );
	constraint.setPoweredLinMotor( true );
	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.slider_disableLinearMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setPoweredLinMotor( false );
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.slider_enableAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setTargetAngMotorVelocity( params.velocity );
	constraint.setMaxAngMotorForce( params.acceleration );
	constraint.setPoweredAngMotor( true );
	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.slider_disableAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setPoweredAngMotor( false );
	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};

public_functions.conetwist_setLimit = function( params ) {
	_constraints[ params.constraint ].setLimit( params.z, params.y, params.x ); // ZYX order
};
public_functions.conetwist_enableMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.enableMotor( true );
	constraint.getRigidBodyA().activate();
	constraint.getRigidBodyB().activate();
};
public_functions.conetwist_setMaxMotorImpulse = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.setMaxMotorImpulse( params.max_impulse );
	constraint.getRigidBodyA().activate();
	constraint.getRigidBodyB().activate();
};
public_functions.conetwist_setMotorTarget = function( params ) {
	var constraint = _constraints[ params.constraint ];

	_quat.setX(params.x);
	_quat.setY(params.y);
	_quat.setZ(params.z);
	_quat.setW(params.w);

	constraint.setMotorTarget(_quat);

	constraint.getRigidBodyA().activate();
	constraint.getRigidBodyB().activate();
};
public_functions.conetwist_disableMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];
	constraint.enableMotor( false );
	constraint.getRigidBodyA().activate();
	constraint.getRigidBodyB().activate();
};

public_functions.dof_setLinearLowerLimit = function( params ) {
	var constraint = _constraints[ params.constraint ];

	_vec3_1.setX(params.x);
	_vec3_1.setY(params.y);
	_vec3_1.setZ(params.z);

	constraint.setLinearLowerLimit(_vec3_1);

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_setLinearUpperLimit = function( params ) {
	var constraint = _constraints[ params.constraint ];

	_vec3_1.setX(params.x);
	_vec3_1.setY(params.y);
	_vec3_1.setZ(params.z);

	constraint.setLinearUpperLimit(_vec3_1);

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_setAngularLowerLimit = function( params ) {
	var constraint = _constraints[ params.constraint ];

	_vec3_1.setX(params.x);
	_vec3_1.setY(params.y);
	_vec3_1.setZ(params.z);

	constraint.setAngularLowerLimit(_vec3_1);

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_setAngularUpperLimit = function( params ) {
	var constraint = _constraints[ params.constraint ];

	_vec3_1.setX(params.x);
	_vec3_1.setY(params.y);
	_vec3_1.setZ(params.z);

	constraint.setAngularUpperLimit(_vec3_1);

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_enableAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];

	var motor = constraint.getRotationalLimitMotor( params.which );
	motor.set_m_enableMotor( true );

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_configureAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];

	var motor = constraint.getRotationalLimitMotor( params.which );

	motor.set_m_loLimit( params.low_angle );
	motor.set_m_hiLimit( params.high_angle );
	motor.set_m_targetVelocity( params.velocity );
	motor.set_m_maxMotorForce( params.max_force );

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};
public_functions.dof_disableAngularMotor = function( params ) {
	var constraint = _constraints[ params.constraint ];

	var motor = constraint.getRotationalLimitMotor( params.which );
	motor.set_m_enableMotor( false );

	constraint.getRigidBodyA().activate();
	if ( constraint.getRigidBodyB() ) {
		constraint.getRigidBodyB().activate();
	}
};

reportWorld = function() {
	var index, object,
		transform, origin, rotation,
		offset = 0,
		i = 0;

	if ( SUPPORT_TRANSFERABLE ) {
		if ( worldreport.length < 2 + _num_objects * WORLDREPORT_ITEMSIZE ) {
			worldreport = new Float32Array(
				2 + // message id & # objects in report
				( Math.ceil( _num_objects / REPORT_CHUNKSIZE ) * REPORT_CHUNKSIZE ) * WORLDREPORT_ITEMSIZE // # of values needed * item size
			);
			worldreport[0] = MESSAGE_TYPES.WORLDREPORT;
		}
	}

	worldreport[1] = _num_objects; // record how many objects we're reporting on

	//for ( i = 0; i < worldreport[1]; i++ ) {
	for ( index in _objects ) {
		if ( _objects.hasOwnProperty( index ) ) {
			object = _objects[index];

			// #TODO: we can't use center of mass transform when center of mass can change,
			//        but getMotionState().getWorldTransform() screws up on objects that have been moved
			//object.getMotionState().getWorldTransform( transform );
			transform = object.getCenterOfMassTransform();

			origin = transform.getOrigin();
			rotation = transform.getRotation();

			// add values to report
			offset = 2 + (i++) * WORLDREPORT_ITEMSIZE;

			worldreport[ offset ] = object.id;

			worldreport[ offset + 1 ] = origin.x();
			worldreport[ offset + 2 ] = origin.y();
			worldreport[ offset + 3 ] = origin.z();

			worldreport[ offset + 4 ] = rotation.x();
			worldreport[ offset + 5 ] = rotation.y();
			worldreport[ offset + 6 ] = rotation.z();
			worldreport[ offset + 7 ] = rotation.w();

			_vector = object.getLinearVelocity();
			worldreport[ offset + 8 ] = _vector.x();
			worldreport[ offset + 9 ] = _vector.y();
			worldreport[ offset + 10 ] = _vector.z();

			_vector = object.getAngularVelocity();
			worldreport[ offset + 11 ] = _vector.x();
			worldreport[ offset + 12 ] = _vector.y();
			worldreport[ offset + 13 ] = _vector.z();
		}
	}


	if ( SUPPORT_TRANSFERABLE ) {
		transferableMessage( worldreport.buffer, [worldreport.buffer] );
	} else {
		transferableMessage( worldreport );
	}

};

reportCollisions = function() {
	var i, offset,
		dp = world.getDispatcher(),
		num = dp.getNumManifolds(),
		manifold, num_contacts, j, pt,
		_collided = false;

	if ( SUPPORT_TRANSFERABLE ) {
		if ( collisionreport.length < 2 + num * COLLISIONREPORT_ITEMSIZE ) {
			collisionreport = new Float32Array(
				2 + // message id & # objects in report
				( Math.ceil( _num_objects / REPORT_CHUNKSIZE ) * REPORT_CHUNKSIZE ) * COLLISIONREPORT_ITEMSIZE // # of values needed * item size
			);
			collisionreport[0] = MESSAGE_TYPES.COLLISIONREPORT;
		}
	}

	collisionreport[1] = 0; // how many collisions we're reporting on

	for ( i = 0; i < num; i++ ) {
		manifold = dp.getManifoldByIndexInternal( i );

		num_contacts = manifold.getNumContacts();
		if ( num_contacts === 0 ) {
			continue;
		}

		for ( j = 0; j < num_contacts; j++ ) {
			pt = manifold.getContactPoint( j );
			//if ( pt.getDistance() < 0 ) {
				offset = 2 + (collisionreport[1]++) * COLLISIONREPORT_ITEMSIZE;
				collisionreport[ offset ] = _objects_ammo[ manifold.getBody0() ];
				collisionreport[ offset + 1 ] = _objects_ammo[ manifold.getBody1() ];

				_vector = pt.get_m_normalWorldOnB();
				collisionreport[ offset + 2 ] = _vector.x();
				collisionreport[ offset + 3 ] = _vector.y();
				collisionreport[ offset + 4 ] = _vector.z();
				break;
			//}

				transferableMessage( _objects_ammo );

		}
	}


	if ( SUPPORT_TRANSFERABLE ) {
		transferableMessage( collisionreport.buffer, [collisionreport.buffer] );
	} else {
		transferableMessage( collisionreport );
	}
};

reportVehicles = function() {
	var index, vehicle,
		transform, origin, rotation,
		offset = 0,
		i = 0, j = 0;

	if ( SUPPORT_TRANSFERABLE ) {
		if ( vehiclereport.length < 2 + _num_wheels * VEHICLEREPORT_ITEMSIZE ) {
			vehiclereport = new Float32Array(
				2 + // message id & # objects in report
				( Math.ceil( _num_wheels / REPORT_CHUNKSIZE ) * REPORT_CHUNKSIZE ) * VEHICLEREPORT_ITEMSIZE // # of values needed * item size
			);
			vehiclereport[0] = MESSAGE_TYPES.VEHICLEREPORT;
		}
	}

	for ( index in _vehicles ) {
		if ( _vehicles.hasOwnProperty( index ) ) {
			vehicle = _vehicles[index];

			for ( j = 0; j < vehicle.getNumWheels(); j++ ) {

				//vehicle.updateWheelTransform( j, true );

				//transform = vehicle.getWheelTransformWS( j );
				transform = vehicle.getWheelInfo( j ).get_m_worldTransform();

				origin = transform.getOrigin();
				rotation = transform.getRotation();

				// add values to report
				offset = 1 + (i++) * VEHICLEREPORT_ITEMSIZE;

				vehiclereport[ offset ] = index;
				vehiclereport[ offset + 1 ] = j;

				vehiclereport[ offset + 2 ] = origin.x();
				vehiclereport[ offset + 3 ] = origin.y();
				vehiclereport[ offset + 4 ] = origin.z();

				vehiclereport[ offset + 5 ] = rotation.x();
				vehiclereport[ offset + 6 ] = rotation.y();
				vehiclereport[ offset + 7 ] = rotation.z();
				vehiclereport[ offset + 8 ] = rotation.w();

			}

		}
	}

	if ( j !== 0 ) {
		if ( SUPPORT_TRANSFERABLE ) {
			transferableMessage( vehiclereport.buffer, [vehiclereport.buffer] );
		} else {
			transferableMessage( vehiclereport );
		}
	}
};

reportConstraints = function() {
	var index, constraint,
		offset_body,
		transform, origin,
		offset = 0,
		i = 0;

	if ( SUPPORT_TRANSFERABLE ) {
		if ( constraintreport.length < 2 + _num_constraints * CONSTRAINTREPORT_ITEMSIZE ) {
			constraintreport = new Float32Array(
				2 + // message id & # objects in report
				( Math.ceil( _num_constraints / REPORT_CHUNKSIZE ) * REPORT_CHUNKSIZE ) * CONSTRAINTREPORT_ITEMSIZE // # of values needed * item size
			);
			constraintreport[0] = MESSAGE_TYPES.CONSTRAINTREPORT;
		}
	}

	for ( index in _constraints ) {
		if ( _constraints.hasOwnProperty( index ) ) {
			constraint = _constraints[index];
			offset_body = constraint.getRigidBodyA();
			transform = constraint.getFrameOffsetA();
			origin = transform.getOrigin();

			// add values to report
			offset = 1 + (i++) * CONSTRAINTREPORT_ITEMSIZE;

			constraintreport[ offset ] = index;
			constraintreport[ offset + 1 ] = offset_body.id;
			constraintreport[ offset + 2 ] = origin.getX();
			constraintreport[ offset + 3 ] = origin.getY();
			constraintreport[ offset + 4 ] = origin.getZ();
			constraintreport[ offset + 5 ] = constraint.getAppliedImpulse();
		}
	}


	if ( i !== 0 ) {
		if ( SUPPORT_TRANSFERABLE ) {
			transferableMessage( constraintreport.buffer, [constraintreport.buffer] );
		} else {
			transferableMessage( constraintreport );
		}
	}

};

self.onmessage = function( event ) {

	if ( event.data instanceof Float32Array ) {
		// transferable object

		switch ( event.data[0] ) {
			case MESSAGE_TYPES.WORLDREPORT:
				worldreport = new Float32Array( event.data );
				break;

			case MESSAGE_TYPES.COLLISIONREPORT:
				collisionreport = new Float32Array( event.data );
				break;

			case MESSAGE_TYPES.VEHICLEREPORT:
				vehiclereport = new Float32Array( event.data );
				break;

			case MESSAGE_TYPES.CONSTRAINTREPORT:
				constraintreport = new Float32Array( event.data );
				break;
		}

		return;
	}

	if ( event.data.cmd && public_functions[event.data.cmd] ) {
		//if ( event.data.params.id !== undefined && _objects[event.data.params.id] === undefined && event.data.cmd !== 'addObject' && event.data.cmd !== 'registerMaterial' ) return;
		public_functions[event.data.cmd]( event.data.params );
	}

};