About Contact me Presentations rss feed  rss

Converting a small game from C# to F# part 1

15 Sep 2014

As part of the workshop I am preparing to run on a bunch of places in North America, I created a small clone of Breakout and just ported it to F#. I am going to be explaining a little about how the engine works and that will be intertwined with an (hopefully) fun intro to F#.

Duality is

Follow the link for Adam’s getting started.

In the previous post I showed how to create components in Duality, so I started of with one the simplest component, ScoreComponent, that component looked like this

    public class ScoreComponent : Component, ICmpUpdatable
        private int _score;

        public int Score { get { return _score; } }

        public void IncreaseScore(int amount)
            Score += amount;

        public void OnUpdate()
            var textRenderer = GameObj.GetComponent<TextRenderer>();
            if (textRenderer != null) 
                textRenderer.Text.SourceText = "Score: "+ Score;


When converting to F# it looks pretty similar, at least initially

type ScoreComponentF() = 
    inherit Component()

    let mutable score =0

    member this.Score = score
    member this.IncreaseScore amount =
        score <- score + amount        
    interface ICmpUpdatable with 
        member this.OnUpdate() =
            let textRenderer = this.GameObj.GetComponent<TextRenderer>()
            if (textRenderer <> null) then
                textRenderer.Text.SourceText <- sprintf "Score: %i"  this.Score

The method OnUpdate could be improved. A first iteration would look like:

    interface ICmpUpdatable with 
        member this.OnUpdate() =
            match this.GameObj.GetComponent<TextRenderer>() with
            | null -> ()
            | textRenderer -> textRenderer.Text.SourceText <- sprintf "Score: %i"  this.Score

This is nice but this pattern(?), do something if the component exist, is rather common and it would be nice to turn this into an option type.

We will continue in the next post :D

Fun and games FTW!!

OT: Best of luck to all the people involved in Minecraft and this transition to Microsoft. I can emphatize with where @notch is coming from.

If you want to discuss this post, the best place right now for me is mastodon, please message me with your comment/question.