Unity Shader實現黑幕過場效果

//黑幕過場著色器
 
Shader "Custom/BlackScreenSpread"
{
 Properties
 {
  _Color("Main Color", Color) = (1,1,1,1)
  _MainTex("Base (RGB)", 2D) = "white" {}
  _Radius("Radius",float)=1.5
  _Center_X("Center_X", float) =0.5 
  _Center_Y("Center_Y", float) =0.5
  _Sharp("Sharp", float) = 100
 }
 
 SubShader
 {
  Pass
  {
   ZTest Always Cull Off ZWrite Off
   Fog{ Mode off
  }
   
  CGPROGRAM
  #pragma vertex vert_img        
  #pragma fragment frag             
  #include "UnityCG.cginc"  
 
  fixed4 _Color;
  sampler2D _MainTex;
  float _Radius;
  float _Center_X;
  float _Center_Y;
  float _Sharp;
 
  float _tanh(float x)
  {
   return 2.0f / (1.0f + exp(-2.0f * x)) - 1.0f;
  }
 
  float4 frag(v2f_img i) : COLOR
  {  
   _Center_X=_Center_X*(_ScreenParams.x / _ScreenParams.y);
   float x = i.uv.x*(_ScreenParams.x / _ScreenParams.y);
   float y = i.uv.y;
 
   float dis = sqrt((x - _Center_X)*(x - _Center_X) + (y - _Center_Y)*(y - _Center_Y));
   float t = _Radius - dis;
   float rt = 0.5f + _tanh(t * _Sharp) * 0.5f;
   float col = float4(rt, rt, rt, rt);
   return tex2D(_MainTex, i.uv) * col * _Color;
  }
  ENDCG
 }
 }
 Fallback off
}

using UnityEngine;
 
/// <summary>
/// 後處理的基類
/// </summary>
[ExecuteInEditMode]
[RequireComponent(typeof(Camera))]
public class PostEffectBase : MonoBehaviour
{
    [Header("後處理著色器")]
    public Shader shader = null;
 
    private Material _material = null;
 
    public Material material
    {
        get
        {
            if (_material == null)
            {
                _material = GenerateMaterial(shader);
            }
            return _material;
        }
    }
 
    protected Material GenerateMaterial(Shader shader)
    {
        if (shader == null || shader.isSupported == false)
        {
            return null;
        }
        Material material = new Material(shader);
        material.hideFlags = HideFlags.DontSave;
        if (material)
        {
            return material;
        }
        return null;
    }
}

using UnityEngine;
 
/// <summary>
/// 黑幕過場效果
/// </summary>
[RequireComponent(typeof(Camera))]
public class BlackScreenSpread : PostEffectBase
{
    [Header("黑幕半徑")]
    [Space(25)]
    public float radius;
 
    [Header("黑幕中心")]
    public Vector2 center;
 
    [Header("使用邊緣模糊")]
    public bool useEdgeBlur;
    [Header("邊緣模糊值")]
    public float blur = 10;
 
    public void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        if (material)
        {
            material.SetFloat("_Center_X", center.x);
            material.SetFloat("_Center_Y", center.y);
            material.SetFloat("_Radius", radius);
            material.SetFloat("_Sharp", useEdgeBlur ? blur : 200);
            Graphics.Blit(source, destination, material);
        }
        else
        {
            Graphics.Blit(source, destination);
        }
    }
}