如何统一获得相机宽度

Question

Problem

I have a spawn manager written in c# which spawns my game object, i use screen.width, to set the maximum screen with and -screen.width to set the minimum screen width for the spawning, but my game object spawns way off the screen.

I am using a portrait camera 2:3 instead of free aspect as my camera view, as i want my game to be in portrait mode

how do i make my game object spawn within the camera widths(max and min)?

my code

public class SpawnManager : MonoBehaviour {

    public int maxBalloons = 100;
    public GameObject balloon;
    public float horizontalMin = -Screen.width;
    public float horizontalMax = Screen.width;
    public float verticalMin = -5.0f;
    public float verticalMax = 1.0f;


    private Vector2 originPosition;


    void Start () {

        originPosition = transform.position;
        Spawn ();

    }

    void Spawn()
    {
        for (int i = 0; i < maxBalloons; i++)
        {
            Vector2 randomPosition = originPosition + new Vector2 (Random.Range(horizontalMin, horizontalMax), Random.Range (verticalMin, verticalMax));

            Instantiate(balloon, randomPosition, Quaternion.identity);
            originPosition = randomPosition;
        }
    }

}

Edit I changed

Vector2 randomPosition = originPosition + new Vector2 (Random.Range(horizontalMin, horizontalMax), Random.Range (verticalMin, verticalMax));

To

Vector2 randomPosition =Camera.ScreenToWorldPoint (originPosition + new Vector2 (Random.Range(horizontalMin, horizontalMax), Random.Range (verticalMin, verticalMax)));

Still did not work as it should

Answer 1

A position on your screen with a X smaller than 0 will be always out of your screen. The bottom left corner of your screen is the origin of your the coordinate (x: 0, y: 0)

But here I think you mingled 2 kinds of positions. The position on your screen, is not the same position in the world space of your scene. It depends where the camera is rendering. The position on the bottom left corner of your screen will not be x:0 y:0 in the world space.

To achieve what you are looking for you need to transform the position on the left and the right of your camera into worldspace positions.

Use Camera.ScreenToWorldPoint to achieve that : https://docs.unity3d.com/ScriptReference/Camera.ScreenToWorldPoint.html