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

public static class CameraExtend
{

    public static Vector3 WorldToCameraSpace(this Camera camera, Vector3 worldPos)
    {
        Vector4 camPos = camera.worldToCameraMatrix * worldPos.ToVector4();
        return camPos.ToVector3();
    }

    public static Vector3 CameraToViewportSpace(this Camera camera, Vector3 camPos)
    {
        Matrix4x4 proj = GL.GetGPUProjectionMatrix(camera.projectionMatrix, false);
        Vector4 clipPos = proj * camPos.ToVector4();
        Vector3 ndcPos = (clipPos / clipPos.w);
        Vector3 viewPos = (ndcPos + Vector3.one) / 2f;
        return viewPos;
    }

    public static Vector3 CameraToScreenSpace(this Camera camera, Vector3 camPos)
    {
        Vector3 viewPos = camera.CameraToViewportSpace(camPos);
        Vector3 screenPos = new Vector3(
            viewPos.x * camera.pixelWidth,
            viewPos.y * camera.pixelHeight,
            viewPos.z
        );
        return screenPos;
    }

}

public class CameraUtility : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        
    }
}