using UnityEngine;

public class Screenshooter : MonoBehaviour
{
    public Camera cam;
    public int width = 3840;
    public int height = 2160;

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.F12))
        {
            RenderTexture rt = new RenderTexture(width, height, 24);
            cam.targetTexture = rt;

            Texture2D image = new Texture2D(width, height, TextureFormat.RGB24, false);
            cam.Render();
            RenderTexture.active = rt;
            image.ReadPixels(new Rect(0, 0, width, height), 0, 0);
            image.Apply();

            cam.targetTexture = null;
            RenderTexture.active = null;
            Destroy(rt);

            System.IO.File.WriteAllBytes(
                "screenshot_4k.png",
                image.EncodeToPNG()
            );
        }
    }
}