Limiting movement of gameObjects

Unity Engine
,
1

Hello there! I’m currently trying to make a Tetris-like game and I’ve been able to get all the tetrominoes to move but I don’t know how to restrict that movement so they don’t go off the screen. I’m trying to get them to stay in a box that is 160x280 (width x height) and the bottom left corner is in (0,0). I’m moving the tetrominos by integers of 20 at a time hence the 20’s in the code. Right now this is the code:

 private float previousTime;
    public float fallTime = 0.8f;
    public static int height = 280;
    public static int width = 160;

    // Start is called before the first frame update
    void Start()
    {
       
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.LeftArrow))
        {
            transform.position += new Vector3(-20, 0, 0);
            if (!ValidMove())
                transform.position -= new Vector3(-20, 0, 0);
        }
        else if (Input.GetKeyDown(KeyCode.RightArrow))
        {
            transform.position += new Vector3(20, 0, 0);
            if (!ValidMove())
                transform.position -= new Vector3(20, 0, 0);
        }

        if(Time.time - previousTime > (Input.GetKey(KeyCode.DownArrow) ? fallTime / 20 : fallTime))
        {
            transform.position += new Vector3(0, -20, 0);
            previousTime = Time.time;
        }

        bool ValidMove()
        {
            foreach (Transform children in transform)
            {
                int roundedX = Mathf.RoundToInt(children.transform.position.x);
                int roundedY = Mathf.RoundToInt(children.transform.position.y);

                if (roundedX < 0 || roundedX >= width || roundedY < 0 ||roundedY >= height)
                {
                    return false;
                }
            }

            return true;
        }
    }
}

Thank you very much if you can help!

2

You can use clamp on the xvalue. But, you can also just check it yourself to see if the x position -20 or +20 is less or more than you want. But clamp does help make it a little less code to write.

3

To be more specific, the gameObjects won’t stop when they hit the edge of the box. Which means I’m guessing there’s a problem with the boolean because that’s what checks if it hits the wall but I don’t know what would be wrong.

4

Please don’t multi-post. I answered this question over in your other post.

Now if it’s not working, it’s time for you to begin debugging your code. Here’s how:

You must find a way to get the information you need in order to reason about what the problem is.

Once you understand what the problem is, you may begin to reason about a solution to the problem.

What is often happening in these cases is one of the following:

  • the code you think is executing is not actually executing at all
  • the code is executing far EARLIER or LATER than you think
  • the code is executing far LESS OFTEN than you think
  • the code is executing far MORE OFTEN than you think
  • the code is executing on another GameObject than you think it is
  • you’re getting an error or warning and you haven’t noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

  • is this code even running? which parts are running? how often does it run? what order does it run in?
  • what are the values of the variables involved? Are they initialized? Are the values reasonable?
  • are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as Debug.Log("Problem!",this);

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: https://discussions.unity.com/t/700551 or this answer for Android: https://discussions.unity.com/t/699654

If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

https://discussions.unity.com/t/839300/3

When in doubt, print it out!™

Note: the print() function is an alias for Debug.Log() provided by the MonoBehaviour class.