using UnityEngine;
using UnityEngine.Serialization;

namespace Visual
{
    /// <summary>
    /// https://luka712.github.io/2018/07/01/Pixelate-it-Shadertoy-Unity/#:~:text=First%20I%E2%80%99m%20going%20to%20create%20script%20for%20loading%20shader.
    /// </summary>
    [ExecuteInEditMode]
    public class RetroPostProcess : MonoBehaviour
    {
        [FormerlySerializedAs("cellSize")] [SerializeField]
        private Vector2 m_CellSize = new Vector2(4, 4);

        private Material _material;
        private static readonly int ScreenWidth = Shader.PropertyToID("_ScreenWidth");
        private static readonly int ScreenHeight = Shader.PropertyToID("_ScreenHeight");
        private static readonly int CellSizeX = Shader.PropertyToID("_CellSizeX");
        private static readonly int CellSizeY = Shader.PropertyToID("_CellSizeY");

        private void Awake()
        {
            _material = new Material(Shader.Find("Retroed"));
        }

        private void OnRenderImage(RenderTexture source, RenderTexture destination)
        {
            _material.SetFloat(ScreenWidth, Screen.width);
            _material.SetFloat(ScreenHeight, Screen.height);
            _material.SetFloat(CellSizeX, m_CellSize.x);
            _material.SetFloat(CellSizeY, m_CellSize.y);
            Graphics.Blit(source, destination, _material);
        }
    }
}