DragonRuby.rb

class Star
  def initialize grid
    @grid = grid
    @x = (rand @grid.w) * -1
    @y = (rand @grid.h) * -1
    @w    = 4
    @h    = 4
    @s    = 1 + (4.randomize :ratio)
    @path = 'sprites/misc/tiny-star.png'
  end

  def move
    @x += @s
    @y += @s
    @x = (rand @grid.w) * -1 if @x > @grid.right
    @y = (rand @grid.h) * -1 if @y > @grid.top
  end

  def draw_override ffi_draw
    move
    ffi_draw.draw_sprite @x, @y, @w, @h, @path
  end
end

def tick args
  if args.state.tick_count == 0
    args.state.stars = 80000.map { |i| Star.new args.grid }
    args.outputs.static_sprites << args.state.stars
  end

  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

Unity.cs

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using UnityEngine;

public class DisplayFramerate : MonoBehaviour
{
    public TMPro.TMP_Text Text;

    private void Update()
    {
        if (Text != null)
        {
            string fps = ((int)(1f / Time.smoothDeltaTime)).ToString();
            string ms = (Time.smoothDeltaTime * 1000f).ToString("00.0");
            string display = string.Concat("FPS: ", fps, "\nMS: ", ms);
            Text.SetText(display);
        }
    }
}

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using UnityEngine;

public class Star : MonoBehaviour
{
    private float Speed;

    private void Start()
    {
        Speed = Random.Range(Game.Instance.MinSpeed, Game.Instance.MaxSpeed);
    }

    private void Update()
    {
        Vector3 nextPos = this.transform.position;
        nextPos += Speed * new Vector3(1f, 1f, 0f) * Time.deltaTime;
        if (nextPos.x > Game.Instance.BoundsMaxX) nextPos.x = Game.Instance.BoundsMinX;
        if (nextPos.y > Game.Instance.BoundsMaxY) nextPos.y = Game.Instance.BoundsMinY;
        this.transform.position = nextPos;
    }
}

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using UnityEngine;

public static class CameraUtility
{
    public static void GetCameraBounds(out float minX, out float minY, out float maxX, out float maxY, float padding)
    {
        Camera cam = Camera.main;
        Vector3 camPos = cam.transform.position;
        minX = camPos.x - (cam.orthographicSize * cam.aspect) - padding;
        maxX = camPos.x + (cam.orthographicSize * cam.aspect) + padding;
        minY = camPos.y - cam.orthographicSize - padding;
        maxY = camPos.y + cam.orthographicSize + padding;
    }
}

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using UnityEngine;

public class Game : MonoBehaviour
{
    public int StarCount;
    public GameObject StarPrefab;
    public static Game Instance;
    public float MinSpeed = 1f;
    public float MaxSpeed = 4f;
    public float BoundsPadding = 2f;
    public float BoundsMinX, BoundsMaxX, BoundsMinY, BoundsMaxY;

    private void Awake()
    {
        if (Application.isPlaying)
        {
            if (Game.Instance != null) Destroy(this);
            Game.Instance = this;
        }

        CameraUtility.GetCameraBounds(out BoundsMinX, out BoundsMinY, out BoundsMaxX, out BoundsMaxY, BoundsPadding);

        for (int i = 0; i < StarCount; i++)
        {
            Instantiate(StarPrefab,
                        new Vector3(Random.Range(BoundsMinX, BoundsMaxX),
                                    Random.Range(BoundsMinY, BoundsMaxY),
                                    10f),
                        Quaternion.identity);
        }
    }
}