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using UnityEngine;

/// <summary>
/// カメラを常に指定の画角で映すようにします
/// </summary>
[RequireComponent(typeof(Camera))]
public class CameraAspectFitter : MonoBehaviour
{
    [SerializeField] Vector2 size = new Vector2(540f, 960f);
    [SerializeField] float pixelPerUnit = 1f;

    Camera cameraCache;

    void Awake()
    {
        cameraCache = GetComponent<Camera>();
        Fit();
    }

    void Fit()
    {
        var isWideAspectThanScreen = size.x / size.y > Screen.width / Screen.height;
        var scale = isWideAspectThanScreen ? (size.x / Screen.width) : (size.y / Screen.height);
        var fillRatioX = isWideAspectThanScreen ? 1f : (size.x / Screen.width / scale);
        var fillRatioY = isWideAspectThanScreen ? (size.y / Screen.height / scale) : 1f;
        cameraCache.orthographic = true;
        cameraCache.orthographicSize = size.y / 1.92f / pixelPerUnit;
        cameraCache.rect = new Rect((1f - fillRatioX) / 2f, (1f - fillRatioY) / 2f, fillRatioX, fillRatioY);
    }

#if UNITY_EDITOR
    void Update()
    {
        Fit();
    }
#endif
}