AtomicGameEngine-Examples/FeatureExamples/CSharp/Resources/Scripts/32_2DConstraints.cs

//
// Copyright (c) 2008-2015 the Urho3D project.
// Copyright (c) 2015 Xamarin Inc
// Copyright (c) 2016 THUNDERBEAST GAMES LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

using System;
using AtomicEngine;

namespace FeatureExamples
{
    public class Constraints2DSample : Sample
    {
        bool drawDebug;
        Camera camera;
        RigidBody2D dummyBody;
        Node pickedNode;
       
        public Constraints2DSample() : base() { }

        public override void Start()
        {
            base.Start();
            CreateScene();
            SimpleCreateInstructionsWithWasd(", Use PageUp PageDown to zoom.\n Space to toggle debug geometry and joints - F5 to save the scene.");
            SetupViewport();
            SubscribeToEvents();
        }

        void SubscribeToEvents()
        {
            SubscribeToEvent<PostRenderUpdateEvent>(e =>
            {
                // If draw debug mode is enabled, draw viewport debug geometry, which will show eg. drawable bounding boxes and skeleton
                // bones. Note that debug geometry has to be separately requested each frame. Disable depth test so that we can see the
                // bones properly
                if (drawDebug)
                    scene.GetComponent<PhysicsWorld2D>().DrawDebugGeometry();
            });

            SubscribeToEvent<MouseButtonDownEvent>(HandleMouseButtonDown);

            if (TouchEnabled)
            {
                SubscribeToEvent<TouchBeginEvent>(HandleTouchBegin3);
            }
        }

        protected override void Update(float timeStep)
        {
            SimpleMoveCamera2D(timeStep);

            var input = GetSubsystem<Input>();

            if (input.GetKeyDown(Constants.KEY_PAGEUP))
                camera.Zoom = (camera.Zoom * 1.01f);

            if (input.GetKeyDown(Constants.KEY_PAGEDOWN))
                camera.Zoom = (camera.Zoom * 0.99f);

            // Toggle physics debug geometry with space
            if (input.GetKeyPress(Constants.KEY_SPACE))
                drawDebug = !drawDebug;

            // Save scene
            if (input.GetKeyPress(Constants.KEY_F5))
            {
                // scene.SaveXml(FileSystem.ProgramDir + "Data/Scenes/Constraints.xml", "\t");
            }
        }

        void HandleTouchBegin3(TouchBeginEvent args)
        {
            var graphics = GetSubsystem<Graphics>();
            PhysicsWorld2D physicsWorld = scene.GetComponent<PhysicsWorld2D>();
            RigidBody2D rigidBody = physicsWorld.GetRigidBody(new Vector2(args.X, args.Y), uint.MaxValue); // Raycast for RigidBody2Ds to pick
            if (rigidBody != null)
            {
                pickedNode = rigidBody.Node;
                StaticSprite2D staticSprite = pickedNode.GetComponent<StaticSprite2D>();
                staticSprite.Color = (new Color(1.0f, 0.0f, 0.0f, 1.0f)); // Temporary modify color of the picked sprite
                rigidBody = pickedNode.GetComponent<RigidBody2D>();

                // Create a ConstraintMouse2D - Temporary apply this constraint to the pickedNode to allow grasping and moving with touch
                ConstraintMouse2D constraintMouse = pickedNode.CreateComponent<ConstraintMouse2D>();
                Vector3 pos = camera.ScreenToWorldPoint(new Vector3((float)args.X / graphics.Width, (float)args.Y / graphics.Height, 0.0f));
                constraintMouse.Target = new Vector2(pos.X, pos.Y);
                constraintMouse.MaxForce = 1000 * rigidBody.Mass;
                constraintMouse.CollideConnected = true;
                constraintMouse.OtherBody = dummyBody;  // Use dummy body instead of rigidBody. It's better to create a dummy body automatically in ConstraintMouse2D
                constraintMouse.DampingRatio = 0;
            }

            SubscribeToEvent<TouchMoveEvent>(HandleTouchMove3);
            SubscribeToEvent<TouchEndEvent>(HandleTouchEnd3);
        }

        void HandleTouchEnd3(TouchEndEvent args)
        {
            if (pickedNode != null)
            {
                StaticSprite2D staticSprite = pickedNode.GetComponent<StaticSprite2D>();
                staticSprite.Color = (new Color(1.0f, 1.0f, 1.0f, 1.0f)); // Restore picked sprite color
                pickedNode.RemoveComponent<ConstraintMouse2D>(); // Remove temporary constraint
                pickedNode = null;
            }

            UnsubscribeFromEvent<TouchMoveEvent>();
            UnsubscribeFromEvent<TouchEndEvent>();

        }

        void HandleTouchMove3(TouchMoveEvent args)
        {
            if (pickedNode != null)
            {
                var graphics = GetSubsystem<Graphics>();
                ConstraintMouse2D constraintMouse = pickedNode.GetComponent<ConstraintMouse2D>();
                Vector3 pos = camera.ScreenToWorldPoint(new Vector3((float)args.X / graphics.Width, (float)args.Y / graphics.Height, 0.0f));
                constraintMouse.Target = new Vector2(pos.X, pos.Y);
            }
        }

        void HandleMouseButtonDown(MouseButtonDownEvent args)
        {
            Input input = GetSubsystem<Input>();
            PhysicsWorld2D physicsWorld = scene.GetComponent<PhysicsWorld2D>();
            RigidBody2D rigidBody = physicsWorld.GetRigidBody(input.MousePosition.X, input.MousePosition.Y, uint.MaxValue); // Raycast for RigidBody2Ds to pick
            if (rigidBody != null)
            {
                pickedNode = rigidBody.Node;
                //log.Info(pickedNode.name);
                StaticSprite2D staticSprite = pickedNode.GetComponent<StaticSprite2D>();
                staticSprite.Color = (new Color(1.0f, 0.0f, 0.0f, 1.0f)); // Temporary modify color of the picked sprite

                // Create a ConstraintMouse2D - Temporary apply this constraint to the pickedNode to allow grasping and moving with the mouse
                ConstraintMouse2D constraintMouse = pickedNode.CreateComponent<ConstraintMouse2D>();
                constraintMouse.Target = GetMousePositionXY();
                constraintMouse.MaxForce = 1000 * rigidBody.Mass;
                constraintMouse.CollideConnected = true;
                constraintMouse.OtherBody = dummyBody;  // Use dummy body instead of rigidBody. It's better to create a dummy body automatically in ConstraintMouse2D
                constraintMouse.DampingRatio = 0.0f;
            }

            SubscribeToEvent<MouseMoveEvent>(HandleMouseMove);
            SubscribeToEvent<MouseButtonUpEvent>(HandleMouseButtonUp);
        }

        Vector2 GetMousePositionXY()
        {
            Input input = GetSubsystem<Input>();
            var graphics = GetSubsystem<Graphics>();
            Vector3 screenPoint = new Vector3((float)input.MousePosition.X / graphics.Width, (float)input.MousePosition.Y / graphics.Height, 0.0f);
            Vector3 worldPoint = camera.ScreenToWorldPoint(screenPoint);
            return new Vector2(worldPoint.X, worldPoint.Y);
        }


        void HandleMouseMove(MouseMoveEvent args)
        {
            if (pickedNode != null)
            {
                ConstraintMouse2D constraintMouse = pickedNode.GetComponent<ConstraintMouse2D>();
                constraintMouse.Target = GetMousePositionXY();
            }

        }

        void HandleMouseButtonUp(MouseButtonUpEvent args)
        {
            if (pickedNode != null)
            {
                StaticSprite2D staticSprite = pickedNode.GetComponent<StaticSprite2D>();
                staticSprite.Color = (new Color(1.0f, 1.0f, 1.0f, 1.0f)); // Restore picked sprite color
                pickedNode.RemoveComponent<ConstraintMouse2D>();
                pickedNode = null;
            }

            UnsubscribeFromEvent<MouseMoveEvent>();
            UnsubscribeFromEvent<MouseButtonUpEvent>();

        }

        void SetupViewport()
        {
            var renderer = GetSubsystem<Renderer>();
            renderer.SetViewport(0, new Viewport(scene, CameraNode.GetComponent<Camera>()));
        }

        void CreateScene()
        {
            scene = new Scene();
            scene.CreateComponent<Octree>();
            scene.CreateComponent<DebugRenderer>();
            PhysicsWorld2D physicsWorld = scene.CreateComponent<PhysicsWorld2D>(); // Create 2D physics world component
            physicsWorld.DrawJoint = true; // Display the joints (Note that DrawDebugGeometry() must be set to true to acually draw the joints)
            drawDebug = true; // Set DrawDebugGeometry() to true

            // Create camera
            CameraNode = scene.CreateChild("Camera");
            // Set camera's position
            CameraNode.Position = (new Vector3(0.0f, 0.0f, 0.0f)); // Note that Z setting is discarded; use camera.zoom instead (see MoveCamera() below for example)

            camera = CameraNode.CreateComponent<Camera>();
            camera.Orthographic = true;

            var graphics = GetSubsystem<Graphics>();

            camera.OrthoSize = (float)graphics.Height * PixelSize;
            camera.Zoom = 1.2f * Math.Min((float)graphics.Width / 1280.0f, (float)graphics.Height / 800.0f); // Set zoom according to user's resolution to ensure full visibility (initial zoom (1.2) is set for full visibility at 1280x800 resolution)

            // Set up a viewport to the Renderer subsystem so that the 3D scene can be seen
            Viewport viewport = new Viewport(scene, camera);
            Renderer renderer = GetSubsystem<Renderer>();
            renderer.SetViewport(0, viewport);

            Zone zone = renderer.DefaultZone;
            zone.FogColor = (new Color(0.1f, 0.1f, 0.1f)); // Set background color for the scene

            // Create 4x3 grid
            for (uint i = 0; i < 5; ++i)
            {
                Node edgeNode = scene.CreateChild("VerticalEdge");
                RigidBody2D edgeBody = edgeNode.CreateComponent<RigidBody2D>();
                if (dummyBody == null)
                    dummyBody = edgeBody; // Mark first edge as dummy body (used by mouse pick)
                CollisionEdge2D edgeShape = edgeNode.CreateComponent<CollisionEdge2D>();
                edgeShape.SetVertices(new Vector2(i * 2.5f - 5.0f, -3.0f), new Vector2(i * 2.5f - 5.0f, 3.0f));
                edgeShape.Friction = 0.5f; // Set friction
            }

            for (uint j = 0; j < 4; ++j)
            {
                Node edgeNode = scene.CreateChild("HorizontalEdge");
                /*RigidBody2D edgeBody = */
                edgeNode.CreateComponent<RigidBody2D>();
                CollisionEdge2D edgeShape = edgeNode.CreateComponent<CollisionEdge2D>();
                edgeShape.SetVertices(new Vector2(-5.0f, j * 2.0f - 3.0f), new Vector2(5.0f, j * 2.0f - 3.0f));
                edgeShape.Friction = 0.5f; // Set friction
            }

            var cache = GetSubsystem<ResourceCache>();

            // Create a box (will be cloned later)
            Node box = scene.CreateChild("Box");
            box.Position = (new Vector3(0.8f, -2.0f, 0.0f));
            StaticSprite2D boxSprite = box.CreateComponent<StaticSprite2D>();
            boxSprite.Sprite = cache.Get<Sprite2D>("Urho2D/Box.png");
            RigidBody2D boxBody = box.CreateComponent<RigidBody2D>();
            boxBody.BodyType = BodyType2D.BT_DYNAMIC;
            boxBody.LinearDamping = 0.0f;
            boxBody.AngularDamping = 0.0f;
            CollisionBox2D shape = box.CreateComponent<CollisionBox2D>(); // Create box shape
            shape.Size = new Vector2(0.32f, 0.32f); // Set size
            shape.Density = 1.0f; // Set shape density (kilograms per meter squared)
            shape.Friction = 0.5f; // Set friction
            shape.Restitution = 0.1f; // Set restitution (slight bounce)

            // Create a ball (will be cloned later)
            Node ball = scene.CreateChild("Ball");
            ball.Position = (new Vector3(1.8f, -2.0f, 0.0f));
            StaticSprite2D ballSprite = ball.CreateComponent<StaticSprite2D>();
            ballSprite.Sprite = cache.Get<Sprite2D>("Urho2D/Ball.png");
            RigidBody2D ballBody = ball.CreateComponent<RigidBody2D>();
            ballBody.BodyType = BodyType2D.BT_DYNAMIC;
            ballBody.LinearDamping = 0.0f;
            ballBody.AngularDamping = 0.0f;
            CollisionCircle2D ballShape = ball.CreateComponent<CollisionCircle2D>(); // Create circle shape
            ballShape.Radius = 0.16f; // Set radius
            ballShape.Density = 1.0f; // Set shape density (kilograms per meter squared)
            ballShape.Friction = 0.5f; // Set friction
            ballShape.Restitution = 0.6f; // Set restitution: make it bounce

            // Create a polygon
            Node polygon = scene.CreateChild("Polygon");
            polygon.Position = (new Vector3(1.6f, -2.0f, 0.0f));
            polygon.SetScale(0.7f);
            StaticSprite2D polygonSprite = polygon.CreateComponent<StaticSprite2D>();
            polygonSprite.Sprite = cache.Get<Sprite2D>("Urho2D/Aster.png");
            RigidBody2D polygonBody = polygon.CreateComponent<RigidBody2D>();
            polygonBody.BodyType = BodyType2D.BT_DYNAMIC;
            CollisionPolygon2D polygonShape = polygon.CreateComponent<CollisionPolygon2D>();
            polygonShape.VertexCount = 6; // Set number of vertices (mandatory when using SetVertex())
            polygonShape.SetVertex(0, new Vector2(-0.8f, -0.3f));
            polygonShape.SetVertex(1, new Vector2(0.5f, -0.8f));
            polygonShape.SetVertex(2, new Vector2(0.8f, -0.3f));
            polygonShape.SetVertex(3, new Vector2(0.8f, 0.5f));
            polygonShape.SetVertex(4, new Vector2(0.5f, 0.9f));
            polygonShape.SetVertex(5, new Vector2(-0.5f, 0.7f));
            polygonShape.Density = 1.0f; // Set shape density (kilograms per meter squared)
            polygonShape.Friction = 0.3f; // Set friction
            polygonShape.Restitution = 0.0f; // Set restitution (no bounce)

            // Create a ConstraintDistance2D
            CreateFlag("ConstraintDistance2D", -4.97f, 3.0f); // Display Text3D flag
            Node boxDistanceNode = box.Clone(CreateMode.REPLICATED);
            Node ballDistanceNode = ball.Clone(CreateMode.REPLICATED);
            RigidBody2D ballDistanceBody = ballDistanceNode.GetComponent<RigidBody2D>();
            boxDistanceNode.Position = (new Vector3(-4.5f, 2.0f, 0.0f));
            ballDistanceNode.Position = (new Vector3(-3.0f, 2.0f, 0.0f));

            ConstraintDistance2D constraintDistance = boxDistanceNode.CreateComponent<ConstraintDistance2D>(); // Apply ConstraintDistance2D to box
            constraintDistance.OtherBody = ballDistanceBody; // Constrain ball to box
            constraintDistance.OwnerBodyAnchor = boxDistanceNode.Position2D;
            constraintDistance.OtherBodyAnchor = ballDistanceNode.Position2D;
            // Make the constraint soft (comment to make it rigid, which is its basic behavior)
            constraintDistance.FrequencyHz = 4.0f;
            constraintDistance.DampingRatio = 0.5f;

            // Create a ConstraintFriction2D ********** Not functional. From Box2d samples it seems that 2 anchors are required, Urho2D only provides 1, needs investigation ***********
            CreateFlag("ConstraintFriction2D", 0.03f, 1.0f); // Display Text3D flag
            Node boxFrictionNode = box.Clone(CreateMode.REPLICATED);
            Node ballFrictionNode = ball.Clone(CreateMode.REPLICATED);
            boxFrictionNode.Position = (new Vector3(0.5f, 0.0f, 0.0f));
            ballFrictionNode.Position = (new Vector3(1.5f, 0.0f, 0.0f));

            ConstraintFriction2D constraintFriction = boxFrictionNode.CreateComponent<ConstraintFriction2D>(); // Apply ConstraintDistance2D to box
            constraintFriction.OtherBody = ballFrictionNode.GetComponent<RigidBody2D>(); // Constraint ball to box

            // Create a ConstraintGear2D
            CreateFlag("ConstraintGear2D", -4.97f, -1.0f); // Display Text3D flag
            Node baseNode = box.Clone(CreateMode.REPLICATED);
            RigidBody2D tempBody = baseNode.GetComponent<RigidBody2D>(); // Get body to make it static
            tempBody.BodyType = BodyType2D.BT_STATIC;
            baseNode.Position = (new Vector3(-3.7f, -2.5f, 0.0f));
            Node ball1Node = ball.Clone(CreateMode.REPLICATED);
            ball1Node.Position = (new Vector3(-4.5f, -2.0f, 0.0f));
            RigidBody2D ball1Body = ball1Node.GetComponent<RigidBody2D>();
            Node ball2Node = ball.Clone(CreateMode.REPLICATED);
            ball2Node.Position = (new Vector3(-3.0f, -2.0f, 0.0f));
            RigidBody2D ball2Body = ball2Node.GetComponent<RigidBody2D>();

            ConstraintRevolute2D gear1 = baseNode.CreateComponent<ConstraintRevolute2D>(); // Apply constraint to baseBox
            gear1.OtherBody = ball1Body; // Constrain ball1 to baseBox
            gear1.Anchor = ball1Node.Position2D;
            ConstraintRevolute2D gear2 = baseNode.CreateComponent<ConstraintRevolute2D>(); // Apply constraint to baseBox
            gear2.OtherBody = ball2Body; // Constrain ball2 to baseBox
            gear2.Anchor = ball2Node.Position2D;

            ConstraintGear2D constraintGear = ball1Node.CreateComponent<ConstraintGear2D>(); // Apply constraint to ball1
            constraintGear.OtherBody = ball2Body; // Constrain ball2 to ball1
            constraintGear.OwnerConstraint = gear1;
            constraintGear.OtherConstraint = gear2;
            constraintGear.Ratio = 1.0f;

            ball1Body.ApplyAngularImpulse(0.015f, true); // Animate

            // Create a vehicle from a compound of 2 ConstraintWheel2Ds
            CreateFlag("ConstraintWheel2Ds compound", -2.45f, -1.0f); // Display Text3D flag
            Node car = box.Clone(CreateMode.REPLICATED);
            car.Scale = new Vector3(4.0f, 1.0f, 0.0f);
            car.Position = (new Vector3(-1.2f, -2.3f, 0.0f));
            StaticSprite2D tempSprite = car.GetComponent<StaticSprite2D>(); // Get car Sprite in order to draw it on top
            tempSprite.OrderInLayer = 0; // Draw car on top of the wheels (set to -1 to draw below)
            Node ball1WheelNode = ball.Clone(CreateMode.REPLICATED);
            ball1WheelNode.Position = (new Vector3(-1.6f, -2.5f, 0.0f));
            Node ball2WheelNode = ball.Clone(CreateMode.REPLICATED);
            ball2WheelNode.Position = (new Vector3(-0.8f, -2.5f, 0.0f));

            ConstraintWheel2D wheel1 = car.CreateComponent<ConstraintWheel2D>();
            wheel1.OtherBody = ball1WheelNode.GetComponent<RigidBody2D>();
            wheel1.Anchor = ball1WheelNode.Position2D;
            wheel1.Axis = new Vector2(0.0f, 1.0f);
            wheel1.MaxMotorTorque = 20.0f;
            wheel1.FrequencyHz = 4.0f;
            wheel1.DampingRatio = 0.4f;

            ConstraintWheel2D wheel2 = car.CreateComponent<ConstraintWheel2D>();
            wheel2.OtherBody = ball2WheelNode.GetComponent<RigidBody2D>();
            wheel2.Anchor = ball2WheelNode.Position2D;
            wheel2.Axis = new Vector2(0.0f, 1.0f);
            wheel2.MaxMotorTorque = 10.0f;
            wheel2.FrequencyHz = 4.0f;
            wheel2.DampingRatio = 0.4f;

            // ConstraintMotor2D
            CreateFlag("ConstraintMotor2D", 2.53f, -1.0f); // Display Text3D flag
            Node boxMotorNode = box.Clone(CreateMode.REPLICATED);
            tempBody = boxMotorNode.GetComponent<RigidBody2D>(); // Get body to make it static
            tempBody.BodyType = BodyType2D.BT_STATIC;
            Node ballMotorNode = ball.Clone(CreateMode.REPLICATED);
            boxMotorNode.Position = (new Vector3(3.8f, -2.1f, 0.0f));
            ballMotorNode.Position = (new Vector3(3.8f, -1.5f, 0.0f));

            ConstraintMotor2D constraintMotor = boxMotorNode.CreateComponent<ConstraintMotor2D>();
            constraintMotor.OtherBody = ballMotorNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintMotor.LinearOffset = new Vector2(0.0f, 0.8f); // Set ballNode position relative to boxNode position = (0,0)
            constraintMotor.AngularOffset = 0.1f;
            constraintMotor.MaxForce = 5.0f;
            constraintMotor.MaxTorque = 10.0f;
            constraintMotor.CorrectionFactor = 1.0f;
            constraintMotor.CollideConnected = true; // doesn't work

            // ConstraintMouse2D is demonstrated in HandleMouseButtonDown() function. It is used to "grasp" the sprites with the mouse.
            CreateFlag("ConstraintMouse2D", 0.03f, -1.0f); // Display Text3D flag

            // Create a ConstraintPrismatic2D
            CreateFlag("ConstraintPrismatic2D", 2.53f, 3.0f); // Display Text3D flag
            Node boxPrismaticNode = box.Clone(CreateMode.REPLICATED);
            tempBody = boxPrismaticNode.GetComponent<RigidBody2D>(); // Get body to make it static
            tempBody.BodyType = BodyType2D.BT_STATIC;
            Node ballPrismaticNode = ball.Clone(CreateMode.REPLICATED);
            boxPrismaticNode.Position = new Vector3(3.3f, 2.5f, 0.0f);
            ballPrismaticNode.Position = new Vector3(4.3f, 2.0f, 0.0f);

            ConstraintPrismatic2D constraintPrismatic = boxPrismaticNode.CreateComponent<ConstraintPrismatic2D>();
            constraintPrismatic.OtherBody = ballPrismaticNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintPrismatic.Axis = new Vector2(1.0f, 1.0f); // Slide from [0,0] to [1,1]
            constraintPrismatic.Anchor = new Vector2(4.0f, 2.0f);
            constraintPrismatic.LowerTranslation = -1.0f;
            constraintPrismatic.UpperTranslation = 0.5f;
            constraintPrismatic.EnableLimit = true;
            constraintPrismatic.MaxMotorForce = 1.0f;
            constraintPrismatic.MotorSpeed = 0.0f;

            // ConstraintPulley2D
            CreateFlag("ConstraintPulley2D", 0.03f, 3.0f); // Display Text3D flag
            Node boxPulleyNode = box.Clone(CreateMode.REPLICATED);
            Node ballPulleyNode = ball.Clone(CreateMode.REPLICATED);
            boxPulleyNode.Position = (new Vector3(0.5f, 2.0f, 0.0f));
            ballPulleyNode.Position = (new Vector3(2.0f, 2.0f, 0.0f));

            ConstraintPulley2D constraintPulley = boxPulleyNode.CreateComponent<ConstraintPulley2D>(); // Apply constraint to box
            constraintPulley.OtherBody = ballPulleyNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintPulley.OwnerBodyAnchor = boxPulleyNode.Position2D;
            constraintPulley.OtherBodyAnchor = ballPulleyNode.Position2D;
            constraintPulley.OwnerBodyGroundAnchor = boxPulleyNode.Position2D + new Vector2(0.0f, 1.0f);
            constraintPulley.OtherBodyGroundAnchor = ballPulleyNode.Position2D + new Vector2(0.0f, 1.0f);
            constraintPulley.Ratio = 1.0f; // Weight ratio between ownerBody and otherBody

            // Create a ConstraintRevolute2D
            CreateFlag("ConstraintRevolute2D", -2.45f, 3.0f); // Display Text3D flag
            Node boxRevoluteNode = box.Clone(CreateMode.REPLICATED);
            tempBody = boxRevoluteNode.GetComponent<RigidBody2D>(); // Get body to make it static
            tempBody.BodyType = BodyType2D.BT_STATIC;
            Node ballRevoluteNode = ball.Clone(CreateMode.REPLICATED);
            boxRevoluteNode.Position = (new Vector3(-2.0f, 1.5f, 0.0f));
            ballRevoluteNode.Position = (new Vector3(-1.0f, 2.0f, 0.0f));

            ConstraintRevolute2D constraintRevolute = boxRevoluteNode.CreateComponent<ConstraintRevolute2D>(); // Apply constraint to box
            constraintRevolute.OtherBody = ballRevoluteNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintRevolute.Anchor = new Vector2(-1.0f, 1.5f);
            constraintRevolute.LowerAngle = -1.0f; // In radians
            constraintRevolute.UpperAngle = 0.5f; // In radians
            constraintRevolute.EnableLimit = true;
            constraintRevolute.MaxMotorTorque = 10.0f;
            constraintRevolute.MotorSpeed = 0.0f;
            constraintRevolute.EnableMotor = true;

            // Create a ConstraintRope2D
            CreateFlag("ConstraintRope2D", -4.97f, 1.0f); // Display Text3D flag
            Node boxRopeNode = box.Clone(CreateMode.REPLICATED);
            tempBody = boxRopeNode.GetComponent<RigidBody2D>();
            tempBody.BodyType = BodyType2D.BT_STATIC;
            Node ballRopeNode = ball.Clone(CreateMode.REPLICATED);
            boxRopeNode.Position = (new Vector3(-3.7f, 0.7f, 0.0f));
            ballRopeNode.Position = (new Vector3(-4.5f, 0.0f, 0.0f));

            ConstraintRope2D constraintRope = boxRopeNode.CreateComponent<ConstraintRope2D>();
            constraintRope.OtherBody = ballRopeNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintRope.OwnerBodyAnchor = new Vector2(0.0f, -0.5f); // Offset from box (OwnerBody) : the rope is rigid from OwnerBody center to this ownerBodyAnchor
            constraintRope.MaxLength = 0.9f; // Rope length
            constraintRope.CollideConnected = true;

            // Create a ConstraintWeld2D
            CreateFlag("ConstraintWeld2D", -2.45f, 1.0f); // Display Text3D flag
            Node boxWeldNode = box.Clone(CreateMode.REPLICATED);
            Node ballWeldNode = ball.Clone(CreateMode.REPLICATED);
            boxWeldNode.Position = (new Vector3(-0.5f, 0.0f, 0.0f));
            ballWeldNode.Position = (new Vector3(-2.0f, 0.0f, 0.0f));

            ConstraintWeld2D constraintWeld = boxWeldNode.CreateComponent<ConstraintWeld2D>();
            constraintWeld.OtherBody = ballWeldNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintWeld.Anchor = boxWeldNode.Position2D;
            constraintWeld.FrequencyHz = 4.0f;
            constraintWeld.DampingRatio = 0.5f;

            // Create a ConstraintWheel2D
            CreateFlag("ConstraintWheel2D", 2.53f, 1.0f); // Display Text3D flag
            Node boxWheelNode = box.Clone(CreateMode.REPLICATED);
            Node ballWheelNode = ball.Clone(CreateMode.REPLICATED);
            boxWheelNode.Position = (new Vector3(3.8f, 0.0f, 0.0f));
            ballWheelNode.Position = (new Vector3(3.8f, 0.9f, 0.0f));

            ConstraintWheel2D constraintWheel = boxWheelNode.CreateComponent<ConstraintWheel2D>();
            constraintWheel.OtherBody = ballWheelNode.GetComponent<RigidBody2D>(); // Constrain ball to box
            constraintWheel.Anchor = ballWheelNode.Position2D;
            constraintWheel.Axis = new Vector2(0.0f, 1.0f);
            constraintWheel.EnableMotor = true;
            constraintWheel.MaxMotorTorque = 1.0f;
            constraintWheel.MotorSpeed = 0.0f;
            constraintWheel.FrequencyHz = 4.0f;
            constraintWheel.DampingRatio = 0.5f;
            constraintWheel.CollideConnected = true; // doesn't work
        }

        void CreateFlag(string text, float x, float y) // Used to create Tex3D flags
        {
            /*
            Node flagNode = scene.CreateChild("Flag");
            flagNode.Position = (new Vector3(x, y, 0.0f));
            Text3D flag3D = flagNode.CreateComponent<Text3D>(); // We use Text3D in order to make the text affected by zoom (so that it sticks to 2D)
            flag3D.Text = text;
            var cache = ResourceCache;
            flag3D.SetFont(cache.GetFont("Fonts/Anonymous Pro.ttf"), 15);
            */
        }
        
    }
}