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

public class DepthFog : MonoBehaviour
{
    Camera Cam;

    Material fogmat;

    public float StartDistance;

    public float EndDistance;

    public float Height;

    public Color FogCol;

    void Awake()
    {
        fogmat = new Material(Shader.Find("Hidden/DepthFog"));
        Cam = this.GetComponent<Camera>();
    }

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

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        if (fogmat == null|| Cam==null) return;
        Shader.SetGlobalFloat("_StartDistance", StartDistance);
        Shader.SetGlobalFloat("_EndDistance", EndDistance);
        Shader.SetGlobalFloat("_Height", Height);
        Shader.SetGlobalColor("_FogCol", FogCol);

        Matrix4x4 vp = GL.GetGPUProjectionMatrix(Cam.projectionMatrix, false) * Cam.worldToCameraMatrix;
        vp = vp.inverse;

        Shader.SetGlobalMatrix("_InvVP", vp);
        Graphics.Blit(source, destination, fogmat);
    }

}