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    Stride for Unity® developers

    Stride and Unity® both use C# and share many concepts, with a few major differences.

    Stride for Unity® developers

    Editor

    The Stride editor is Game Studio. This is the equivalent of the Unity® Editor.

    Stride and Unity®  interface comparison

    Unity® screenshot taken from Calling a web-service from a Unity3D scene by Kean Walmsley.

    You can customize the Game Studio layout by dragging tabs, similar to Visual Studio.

    For more information about Game Studio, see the Game Studio page.

    Terminology

    Unity® and Stride use mostly common terms, with a few differences:

    Unity® Stride
    Hierarchy panel Entity Tree
    Inspector Property Grid
    Project browser Asset View
    Scene view Scene Editor
    GameObject Entity
    MonoBehaviour SyncScript, AsyncScript, StartupScript

    Folders and files

    Like Unity®, Stride projects are stored in a directory that contains:

    • the project .sln solution file, which you can open with Game Studio or any IDE such as Visual Studio

    • a MyGame.Game folder with project source files, dependencies, resources, configurations, and binaries

      Package folder structure

    • Assets contains the asset files which represent elements in your game.

    • Bin contains the compiled binaries and data. Stride creates the folder when you build the project, with a subdirectory for each platform.

    • MyPackage.Game contains your source code.

    • MyPackage.Platform contains additional code for the platforms your project supports. Game Studio creates folders for each platform (eg MyPackage.Windows, MyPackage.Linux, etc). These folders are usually small, and only contain the entry point of the program.

    • obj contains cached files. Game Studio creates this folder when you build your project. To force a complete asset and code rebuild, delete this folder and build the project again.

    • Resources is a suggested location for files such as images and audio files used by your assets.

    Stride and Unity® differ in the following ways:

    • Stride doesn't automatically copy resource files to your project folder when you import them into assets. You have to do this yourself. We recommend you save them in the Resources folder.

    • Stride doesn't require resource files and asset files to be in the same folder. You can save resource files in the Assets folder if you want, but instead we recommend you save them in the Resources folder. This makes sharing your project via version control easier.

    For more information about project structure in Stride, including advice about how to organize and share your files, see the Project structure page.

    Open the project directory from Game Studio

    You can open the project directory from Project > Show in explorer in Game Studio.

    Open project directory from Game Studio

    Game settings

    Unity® saves global settings in separate assets (ie Graphics Settings, Quality Settings, Audio Manager, and so on).

    Stride saves global settings in a single asset, the Game Settings asset. You can configure:

    • The default scene
    • Rendering settings
    • Editor settings
    • Texture settings
    • Physics settings
    • Overrides

    To use the Game Settings asset, in the Asset View, select GameSettings and view its properties in the Property Grid.

    Game settings

    Scenes

    Like Unity®, in Stride you place all objects in a scene. Game Studio stores scenes as separate .sdscene assets in your project directory.

    Set the default scene

    You can have multiple scenes in your project. Stride loads the default scene at runtime.

    To set the default scene:

    1. In the GameSettings properties, next to Default Scene, click Hand icon (Select an asset).

      Set default scene

      The Select an asset window opens.

    2. Select the default scene and click OK.

    For more information about scenes, see Scenes.

    Entities vs GameObjects

    In Unity®, objects in the scene are called GameObjects. In Stride, they're called entities.

    Entities in Stride

    Like GameObjects, entities are carriers for components such as transform components, model components, audio components, and so on. If you're used to working with GameObjects in Unity®, you should have no problem using entities in Game Studio.

    Entity components

    In Stride, you add components to entities just like you add components to GameObjects in Unity®.

    To add a component to entity in Game Studio:

    1. Select the entity you want to add the component to.
    2. In the Property Grid (on the right by default), click Add component and select the component from the drop-down list.

      Add component

    Transform component

    Like GameObjects in Unity®, each entity in Stride has a Transform component which sets its position, rotation, and scale in the world.

    Transform component

    Even empty entities have a Transform component, because every entity in the scene must have a position.

    In Stride, Transform components contain a LocalMatrix and a WorldMatrix that are updated in every Update frame. If you need to force an update sooner than that you can use TranformComponent.UpdateLocalMatrix(), Transform.UpdateWorldMatrix(), or Transform.UpdateLocalFromWorld() to do so, depending on how you need to update the matrix.

    Local Position/Rotation/Scale

    Stride uses position, rotation, and scale to refer to the local position, rotation and scale.

    Unity® Stride
    transform.localPosition Transform.Position
    transform.localRotation Transform.Rotation
    transform.localScale Transform.Scale
    transform.localEulerAngles Transform.RotationEulerXYZ

    World Position/Rotation/Scale

    In comparison to Unity, many of the Transform component's properties related to its location in the world have been moved to the WorldMatrix.

    Unity® Stride
    transform.position Transform.WorldMatrix.TranslationVector
    transform.rotation N/A
    transform.scale N/A
    transform.eulerAngles Transform.WorldMatrix.DecomposeXYZ(out Vector3 rotation)
    transform.scale and transform.position Transform.WorldMatrix.Decompose(out Vector3 scale, out Vector3 translation)
    transform.scale, transform.rotation, and transform.position Transform.WorldMatrix.Decompose(out Vector3 scale, out Quaternion rotation, out Vector3 translation)

    Transform Directions

    Unlike Unity, Stride provides a Backward, Left, and Down property. Note that those are matrix properties, so setting one of those is not enough to properly rotate the matrix.

    Unity® Stride
    transform.forward Transform.WorldMatrix.Forward
    transform.forward * -1 Transform.WorldMatrix.Backward
    transform.right Transform.WorldMatrix.Right
    transform.right * -1 Transform.WorldMatrix.Left
    transform.up Transform.WorldMatrix.Up
    transform.up * -1 Transform.WorldMatrix.Down

    Assets

    In Unity®, you select an asset in the project browser and edit its properties in the Inspector tab.

    Stride is similar. You select an asset in the Asset View and edit its properties in the Property Grid.

    Asset and properties

    For certain types of asset, Game Studio also has dedicated editors:

    • prefabs
    • scenes
    • sprite sheets
    • UI pages
    • UI libraries
    • scripts

    To open the dedicated editor for these types of asset:

    • double-click the asset, or
    • right-click the asset and select Edit asset, or
    • select the asset and type Ctrl + Enter

    The editor opens in a new tab. You can arrange the tabs how you like, or float them as separate windows, just like tabs in web browsers.

    Dedicated Stride editors

    Note

    When you modify resource files outside Game Studio, the corresponding assets update automatically in Game Studio.

    Import assets

    To import an asset, drag it from Explorer to the Asset View. You can also click an Add asset button, navigate to the desired file and specify the type of asset you want to import.

    As soon as you add an asset to your project, you can edit its properties in the Property Grid.

    Add asset

    Note

    Unlike Unity®, Stride doesn't automatically copy resource files to the project directory when you import them to projects.

    Supported file formats

    Like Unity®, Stride supports file formats including:

    Asset type Supported formats
    Models, animations, skeletons .dae, .3ds, obj, .blend, .x, .md2, .md3, .dxf, .fbx
    Sprites, textures, skyboxes .dds, .jpg, .jpeg, .png, .gif, .bmp, .tga, .psd, .tif, .tiff
    Audio .wav, .mp3, .ogg, .aac, .aiff, .flac, .m4a, .wma, .mpc
    Fonts .ttf, .otf

    For more information about assets, see Assets.

    Note
    • Stride currently doesn't support movie files.

    Prefabs

    Like Unity®, Stride uses prefabs. Prefabs are "master" versions of objects that you can reuse wherever you need. When you change a prefab, every instance of the prefab changes too.

    Prefabs in Stride

    Just like with Unity®, in Stride, you can add prefabs to other prefabs. These are called nested prefabs. If you modify a nested prefab, all the dependent prefabs inherit the change automatically.

    For example, imagine you create a Vehicle prefab with acceleration, braking, steering, and so on. Then you nest the Vehicle prefab inside prefabs of different types of vehicles: a taxi, bus,truck, etc. If you adjust a property in the Vehicle prefab, the changes are inherited by all other prefabs. For example, if you increase the Acceleration property in the Vehicle prefab, the acceleration property in the taxi, bus and truck prefabs also increase.

    For more information about using prefabs in Stride, see Prefabs.

    Archetypes

    Archetypes are master assets that control the properties of assets you derive from them. Derived assets are useful when you want to create a "remixed" version of an asset. This is similar to prefabs.

    For example, imagine we have three sphere entities that share a material asset named Metal. Now imagine we want to change the color of only one sphere, but keep its other properties the same. We could duplicate the material asset, change its color, and then apply the new asset to only one sphere. But if we later want to change a different property across all the spheres, we have to modify both assets. This is time-consuming and leaves room for mistakes.

    The better approach is to derive a new asset from the archetype. The derived asset inherits properties from the archetype and lets you override individual properties where you need them. For example, we can derive the sphere's material asset and override its color. Then, if we change the gloss of the archetype, the gloss of all three spheres changes.

    Create derived asset

    You can derive an asset from an archetype, then in turn derive another asset from that derived asset. This way you can create different layers of assets to keep your project organized:

    Archetype
        Derived asset
            Derived asset
    

    For more information about archetypes, see Archetypes.

    Input

    Stride supports a variety of inputs. The code samples below demonstrate the difference in input code between Stride and Unity®.

    For more information about Input in Stride, see Input.

    Unity®

    void Update()
    {
        // true for one frame in which the space bar was pressed
        if(Input.GetKeyDown(KeyCode.Space))
        {
            // Do something.
        }
    
        // true while this joystick button is down
        if (Input.GetButton("joystick button 0"))
        {
            // Do something.
        }
    
        float Horiz = Input.GetAxis("Horizontal");
        float Vert = Input.GetAxis("Vertical");
        //Do something else.
    }
    

    Stride

    public override void Update()
    {
        // true for one frame in which the space bar was pressed
        if(Input.IsKeyDown(Keys.Space))
        {
            // Do something.
        }
    
        // true while this joystick button is down
        if (Input.GameControllers[0].IsButtonDown(0))
        {
            // Do something.
        }
    
        float Horiz = (Input.IsKeyDown(Keys.Left) ? -1f : 0) + (Input.IsKeyDown(Keys.Right) ? 1f : 0);
        float Vert = (Input.IsKeyDown(Keys.Down) ? -1f : 0) + (Input.IsKeyDown(Keys.Up) ? 1f : 0);
        //Do something else.
    }
    

    Physics

    Just like Unity®, Stride has three types of collider:

    • static colliders
    • rigidbodies
    • characters

    They're controlled from scripts in slightly different ways.

    Kinematic rigidbodies

    Unity®

    public Rigidbody rigidBody;
    void Start()
    {
        rigidBody = GetComponent<Rigidbody>();
    }
    
    void EnableRagdoll()
    {
        rigidBody.isKinematic = false;
        rigidBody.detectCollisions = true;
    }
    
    void DisableRagdoll()
    {
        rigidBody.isKinematic = true;
        rigidBody.detectCollisions = false;
    }
    

    Stride

    public class KinematicX : SyncScript
    {
        public RigidbodyComponent component;
    
        public override void Start()
        {
            // Initialization of the script.
            component = Entity.Get<RigidbodyComponent>();
        }
    
        public override void Update()
        {
        }
    
        public void EnableRagdoll()
        {
            component.IsKinematic = false;
            component.ProcessCollisions = true;
        }
    
        public void DisableRagdoll()
        {
            component.IsKinematic = true;
            component.ProcessCollisions = false;
        }
    }
    

    For more information about rigidbodies in Stride, see Rigidbodies.

    Triggers

    Unity®

    // When game object collides with the trigger.
    void OnTriggerEnter(Collider Other)
    {
        Other.transform.localScale = new Vector3(2.0f, 2.0f, 2.0f);
    }
    
    //When game object exits collider space.
    void OnTriggerExit(Collider Other)
    {
        Other.transform.localScale = new Vector3(1.0f, 1.0f, 1.0f);
    }
    

    Stride

    var trigger = Entity.Get<PhysicsComponent>();
    trigger.ProcessCollisions = true;
    
    // Start state machine.
    while (Game.IsRunning)
    {
        // 1. Wait for an entity to collide with the trigger.
        Collision firstCollision = await trigger.NewCollision();
    
        PhysicsComponent otherCollider = trigger == firstCollision.ColliderA
            ? firstCollision.ColliderB
            : firstCollision.ColliderA;
        otherCollider.Entity.Transform.Scale = new Vector3(2.0f, 2.0f, 2.0f);
    
        // 2. Wait for the entity to exit the trigger.
        Collision collision;
    
        do
        {
            collision = await trigger.CollisionEnded();
        }
        while (collision != firstCollision);
    
        otherCollider.Entity.Transform.Scale = new Vector3(1.0f, 1.0f, 1.0f);
    }
    

    For more information about triggers in Stride, see Triggers

    Raycasting

    Unity®

    Collider FindGOCameraIsLookingAt()
    {
        int distance = 50;
    
        // Cast a ray and set it to the mouse cursor position in the game
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if (Physics.Raycast(ray, out hit, distance))
        {
            // Draw invisible ray cast/vector
            Debug.DrawLine(ray.origin, hit.point);
            // Log hit area to the console
            Debug.Log(hit.point);
            return hit.collider;
        }
        return null;
    }
    

    Stride

    public static bool ScreenPositionToWorldPositionRaycast(Vector2 screenPos, CameraComponent camera, Simulation simulation)
    {
        Matrix invViewProj = Matrix.Invert(camera.ViewProjectionMatrix);
    
        Vector3 sPos;
        sPos.X = screenPos.X * 2f - 1f;
        sPos.Y = 1f - screenPos.Y * 2f;
    
        sPos.Z = 0f;
        Vector4 vectorNear = Vector3.Transform(sPos, invViewProj);
        vectorNear /= vectorNear.W;
    
        sPos.Z = 1f;
        Vector4 vectorFar = Vector3.Transform(sPos, invViewProj);
        vectorFar /= vectorFar.W;
    
        HitResult result = simulation.Raycast(vectorNear.XYZ(), vectorFar.XYZ());
        return result.Succeeded;
    }
    

    For more information about Raycasting in Stride, see Raycasting.

    Scripts

    Stride saves scripts in a subfolder in the MyGame.Game folder in the project directory.

    To open a script in the Game Studio script editor, double-click it in the Asset View. The script editor has syntax highlighting, auto-completion, and live diagnostics.

    Stride script editor

    You can also edit scripts in other IDEs, such as Visual Studio. When you edit a script in an external IDE, Stride reloads them automatically.

    If you install the Visual Studio plug-in during the Stride installation, you can open your project in Visual Studio from Game Studio. To do this, in the Game Studio toolbar, click Open in IDE.

    Open project in Visual Studio

    Alternatively, right-click the script in the Asset View and click Open asset file:

    Open asset file

    Event functions (Start, Update, Execute, etc)

    In Unity®, you work with MonoBehaviours with Start(), Update(), and other methods.

    Instead of MonoBehaviours, Stride has three types of scripts: SyncScript, AsyncScript, StartupScript. For more information, see Types of script.

    Unity® MonoBehaviour

    public class BasicMethods : MonoBehaviour
    {
        void Start() { }
        void OnDestroy() { }
        void Update() { }
    }
    

    Stride SyncScript

    public class BasicMethods : SyncScript
    {
        public override void Start() { }
        public override void Cancel() { }        
        public override void Update() { }
    }
    

    Stride AsyncScript

    public class BasicMethods : AsyncScript
    {
        // Declared public member fields and properties that will appear in the game studio
        public override async Task Execute()
        {
            while(Game.IsRunning)
            {
                // Do stuff every new frame
                await Script.NextFrame();
            }
        }
    
        public override void Cancel()
        {
            // Cleanup of the script
        }     
    }
    

    Stride StartupScript

    public class BasicMethods : StartupScript
    {
        // Declared public member fields and properties that will appear in the game studio
        public override void Start()
        {
            // Initialization of the script
        }
    
        public override void Cancel()
        {
            // Cleanup of the script
        }     
    }
    

    Script components

    Like Unity®, in Stride, you attach scripts to entities by adding them as script components.

    Create a script

    To create a script, click Add asset button and select Scripts.

    Create script in Stride

    In Unity®, when you create a MonoBehaviour script, it has two base functions: Start() and Update(). Stride has a SyncScript that works similarly. Like MonoBehaviour, SyncScript has two methods:

    • Start() is called when it the script is loaded.

    • Update() is called every update.

    Unlike MonoBehaviour, you have to use Update() method in every SyncScript, or your code won't work properly.

    If you want your script to be a startup or asynchronous, use the corresponding script types:

    • StartupScript: this script has a single Start() method. It initializes the scene and its content at startup.

    • AsyncScript: an asynchronous script with a single method Execute() and you can use async/await inside that method. Asynchronous scripts aren't loaded one by one like synchronous scripts. Instead, they're all loaded in parallel.

    Reload assemblies

    Unlike Unity®, after you create a script, you have to reload the assemblies manually. To do this, click Reload assemblies in the Game Studio toolbar.

    Reload assemblies

    Add scripts to entities

    1. In the Entity Tree (on the left by default), or in the scene, select the entity you want to add the script to.

      Select an entity

    2. In the Property Grid (on the right by default), click Add component and select the script you want to add.

    Add script component

    In Unity®, script components are grouped under Components > Scripts. In Stride, scripts are not grouped. Instead, Game Studio lists them alphabetically with other components.

    For more information about adding scripts in Stride, see Use a script.

    Scripting gameplay

    Unity® and Stride both use C#. However, scripting gameplay in Stride is a little different from Unity®.

    Instantiate Entity / GameObject

    In Unity®, you use Instantiate to create new object instances. This function makes a copy of UnityEngine.Object and spawns it to the scene.

    Unity®

    public GameObject CarPrefab;
    public Vector3 SpawnPosition;
    public Quaternion SpawnRotation;
    
    void Start()
    {
        GameObject NewGO = (GameObject)Instantiate(CarPrefab, SpawnPosition, SpawnRotation);
        NewGO.name = "NewGameObject1";
    }
    

    Stride

    In Stride, you can instantiate Entities similarly to Unity® GameObjects:

    // Declared public member fields and properties displayed in the Game Studio Property Grid.
    public Prefab CarPrefab;
    public Vector3 SpawnPosition;
    public Quaternion SpawnRotation;
    
    public override void Start()
    {
        // Initialization of the script.
        List<Entity> car = CarPrefab.Instantiate();
        SceneSystem.SceneInstance.RootScene.Entities.AddRange(car);
        car[0].Transform.Position = SpawnPosition;
        car[0].Transform.Rotation = SpawnRotation;
        car[0].Name = "MyNewEntity";
    }
    

    Use default values

    Each class in Unity® has certain default values. If you don't override these properties in the script, the default values will be used. This works the same in Stride:

    Unity®

    public int NewProp = 30;
    public Light MyLightComp = null;
    
    void Start()
    {
        // Create the light component if we don't already have one.
        if (MyLightComp == null)
        {
            MyLightComp = gameObject.AddComponent<Light>();
            MyLightComp.intensity = 3;
        }
    }
    

    Stride

    // Declared public member fields and properties displayed in the Game Studio Property Grid.
    public int NewProp = 30;
    public LightComponent MyLightComponent = null;
    
    public override void Start()
    {
        // Create the light component if we don't already have one.
        if (MyLightComponent == null)
        {
            MyLightComponent = new LightComponent();
            MyLightComponent.Intensity = 3;
            Entity.Add(MyLightComponent);
        }
    }
    

    Disable GameObject/entity

    Unity®

    MyGameObject.SetActive(false);
    

    Stride

    Entity.EnableAll(false, true);
    

    Access component from GameObject/entity

    Unity®

    Light lightComponent = GetComponent<Light>();
    

    Stride

    LightComponent lightComponent = Entity.Get<LightComponent>();
    

    Access GameObject/entity from component

    Unity®

    GameObject ParentGO = lightComponent.gameObject;
    

    Stride

    Entity ParentEntity = lightComponent.Entity;
    

    Log output

    To see the output, in the Game Studio toolbar, under View, enable Output.

    Enable output

    Game Studio displays in the Output tab (at the bottom of Game Studio by default).

    Output tab

    Print debug messages

    To print to the Visual Studio output, use:

    System.Diagnostics.Debug.WriteLine("hello");
    
    Note

    To print debug messages, you have to run the game from Visual Studio, not Game Studio. There's no way to print to the Game Studio output window.


    Unity® is a trademark of Unity Technologies.

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