What about when I'm running the editor?

You may have noticed that the guide so far has focussed on standalone builds, however developing with the editor in mind is no less important.

Setting up the editor entry

Unlike the Game.OnInit entry point, the Game.OnEditorStart entry provides an already loaded app instance, no arguments and a scene.

using SDT4.Managed.Core;
using SDT4.Managed.Editor;

static class MyGameContext 
{
    public static MyGameContext? Instance { get; internal set; }

    public AppInstance Inst { get; }

    internal MyGameContext(AppInstance instance) 
    {
        Inst = instance;
    }
}

static class GameEditor 
{
    static void OnEditorStart(EditorRunContext editorRunContext) 
    {
        Instance = new MyGameContext(editorRunContext.Instance)
    }
}

Inside the EditorRunContext structure, there are many useful fields, such as editor viewports, the running window, the app instance, the scene and the scene script.

// Instead of creating a render canvas of the main window,
// we can just use the primary viewport provided by the editor!

editorRunContext.PrimaryViewport.SetCameraActor(/*...*/);

// It is also possible to use multiple viewports that are open in the editor!
// Note that this is not available when launched in a standalone window!
// editorRunContext.Viewports;

The editor exit

Unlike Game.OnInit, Game.OnEditorStart has a corresponding Game.OnEditorStop that may be defined when the editor shuts down. This is useful for any manual clean up that may be needed to be performed

// ...
static void OnEditorStop(EditorRunContext editorRunContext) 
{
    // Clean up state...
    MyGameContext.Instance = null;

    // Do not dispose the viewports as they are owned by the editor.
    // And the original camera states are restored automatically.
}