godot-csharp-and-gdextension

Godot C# and GDExtension

Overview

Godot runs GDScript, C# (.NET) and native code through GDExtension (C++ via godot-cpp, Rust via godot-rust, and others). Each has a cost: C# needs the .NET build of the editor and cannot export to the web; GDExtension needs a native build per target platform. The repository's existing choice wins; adding a second language is a decision, not a convenience.

Core principle: GDScript by default, C# where the project already is .NET or the team needs it and the web is not a target, GDExtension only for measured hot spots or native libraries.

When which

Mixing GDScript and C# in one project works (cross-language calls go through Call, Get, signals), but keep one language per feature and a clear boundary.

C# nodes

using Godot;

public partial class Player : CharacterBody2D
{
    [Signal] public delegate void HealthChangedEventHandler(int current, int maximum);

    [Export] public PlayerDefinition Definition { get; set; }

    static readonly StringName JumpAction = "jump";
    static readonly StringName MoveLeft = "move_left";
    static readonly StringName MoveRight = "move_right";

    AnimatedSprite2D _sprite;
    int _health;

    public override void _Ready()
    {
        _sprite = GetNode<AnimatedSprite2D>("AnimatedSprite2D");
        _health = Definition.MaxHealth;
    }

    public override void _PhysicsProcess(double delta)
    {
        var v = Velocity;
        v.X = Input.GetAxis(MoveLeft, MoveRight) * Definition.MoveSpeed;
        if (IsOnFloor() && Input.IsActionJustPressed(JumpAction)) v.Y = -Definition.JumpSpeed;
        v.Y += Definition.Gravity * (float)delta;
        Velocity = v;
        MoveAndSlide();
    }

    public void TakeDamage(int amount)
    {
        _health = Mathf.Max(0, _health - amount);
        EmitSignal(SignalName.HealthChanged, _health, Definition.MaxHealth);
    }
}