C# Component System

Component System enables you to implement your application’s logic via a set of building blocks — components, and assign these blocks to nodes, giving them additional functionality. By combining these small and simple blocks you can create a very sophisticated logic system.

A logic component integrates a node and a C# class, containing logic implementation (actions to be performed), defining a set of additional parameters to be used.

Components give you more flexibility in implementing your logic, enabling you to:

• Control which parts of code (implemented as component methods) are to be executed, and which of them are not.
• Control execution order of these parts of code.
• Repeatedly use parts of code, written once, for as many objects as you need, with no modifications required. If you want to change your code, you modify a single source (similar to NodeReferences, if we talk about content).
• Combine certain parts of code to be executed for certain nodes. Build a very sophisticated system from numerous small and simple blocks (like you would use a NodeReference to build a large complex structure using many simple nodes).

Component System is available for all projects using C# (.NET Core) API.

Before starting coding, you should install required software.

See Also#

Proper workflow for programming and building .NET Core-based projects implies a set of requirements:

• .NET Core 3.1 SDK (for both Windows and Linux)
• an IDE or a text editor. Compatibility of different IDEs with the following .NET Core versions is checked:

  IDE	Supported .NET Core version
  MS Visual Studio Code	3.1.x
  MS Visual Studio 2019	3.1.x

  Notice

  Visual Studio Code is the recommended option.

If you work with MS Visual Studio Code, install the C# extension for Visual Studio Code powered by OmniSharp when first opening the component.

In case of any issues with .NET Core, check the Troubleshooting section on .NET Core issues.

Components are created using the Editor. Open the Asset Browser and choose Create > Create C# Component.

Specify a name for the component in the prompt dialog, after which a C# script asset file with the corresponding name will be created in the current directory of the Asset Browser.

Double-click the new script asset to edit the component logic in the default IDE.

Renaming Components#

Essentially components are C# classes inherited from the base Component class.

The work of the C# Component System is based on properties. When you create a new component, it is automatically registered in the ComponentSystem and an internal runtime property is created and associated with the component via a GUID. The following Component class attribute is required for proper work of the component.

[Component(PropertyGuid = "2ae011355ed7f110a202912faa000cc22276e539")]

C# components are listed in the Properties hierarchy, initially they are inherited from the base C# Components property.

Simple Inheritance#

Logic#

Parameters#

public int public_field;

private int private_field;

[ShowInEditor]
private float private_editable_field;

[HideInEditor]
public float public_hidden_field;

Logic implementation described in a component is active at run time only if the component is assigned to a node and both node and component are enabled.

There are several ways of applying a component to a node:

• Select a node, click Add New Property and type the name of a *.cs asset in the Node Properties section of the Node tab. You can do it by dragging the *.cs asset there from the Asset Browser window as well.

  

  Dragging to the node in the Editor Viewport is also supported.

  

• Add a component to a node via code by using the AddComponent<T>(Node node) and Node's AddComponent<T>() functions.

NewComponent component = AddComponent<NewComponent>(node);

NewComponent component = node.AddComponent<NewComponent>();

The logic of a certain component is active only when the component and the corresponding node are enabled. Thus, you can enable/disable logic of each particular component at run time when necessary.

You can assign several components to a single node. The sequence, in which the logic of components is executed, is determined by the order value specified for the corresponding methods (if order values are the same or not specified, the sequence is indeterminable).

Components can interact with other components and nodes.

To run a project using .NET Core click the Play button on the toolbar. This will run an instance of the application in a separate window.

Presets of custom run options are available in the list. By default, there is a single Default (Debug) preset with the default run options. Click the gear icon to configure the current selected preset of custom run options.

In the window that opens the following run options are available:

On changing any custom run option and closing the window, the following actions will be performed depending on the preset selected:

• If the Default (Debug) preset is selected in the list, a new *.launch asset file containing the custom run options will be created in the current folder of the Asset Browser. The corresponding preset will be available in the list of presets.
• If another preset is selected, changes will be applied to it.

UnigineEditor automatically re-compiles your C# components as you make code modifications, save them and get back to the Editor. You will see a green notification on successful compilation, while the red one signalizes that errors were found. Clicking the red message displays the details in the Console.

You can inspect the source code of your C# components while your application is running regardless of whether the application is launched via the Play button right in the UnigineEditor, or built and launched from an IDE.

See the Debugging C# Components article for details.

To create a debug or release build of your C# application, use the File -> Create Build option available in UnigineEditor.

See the Building a Project article for details.

As an example, you can use components to implement logic of enemies chasing the player in your game: regardless of their size, shape, speed, all of them will check player's position, and try to find a path to move closer to it as fast as they can. The code will be basically the same, it'll just use different parameters (speed, mesh, or sounds maybe), so you can put all these parameters to a component (to be able to change them at any time) and the code to the corresponding component class (e.g. place enemies in the world in the Init() and chase the player in the Update() method).

Then you should simply assign the component to all enemy objects and set up parameters (define meshes, sounds, etc.). The Component System will do the rest: execute your code at the corresponding stages of the Engine's main loop for all enemy objects using their specific parameters. Should you decide to modify your code later, you can do that in a single source — component class.

Integration with the Microprofile tool, enables you to monitor overall performance of the Component System, as well as to add profiling information for your custom components.