Shader 灰频效果

灰频效果在游戏中出现也比较多，对于此种效果，是怎么用shader实现的呢？下面就给大家介绍下实现灰频效果的shader代码。

效果图： 

Shader代码：

Shader代码：
Shader "Custom/HuiPin" ｛
    Properties｛
        _MainTex("Main Tex",2D)="white"｛｝
        _LuminosityAmout("GrayScale Amout",Range(0,1))=1.0
    ｝
    SubShader｛
        Pass｛
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            //#pragma fragmentoption ARB_precision_hint_fastest
            #include "UnityCG.cginc"
            sampler2D _MainTex;
            fixed _LuminosityAmout;
            fixed4 frag(v2f_img i):COLOR｛
                fixed4 renderTex = tex2D(_MainTex,i.uv);
                float luminosity = 0.299 * renderTex.r + 0.587 * renderTex.g + 0.114*renderTex.b;
                fixed4 finalColor = lerp(renderTex,luminosity,_LuminosityAmout);
                return finalColor;
            ｝
            ENDCG
        ｝
    ｝
    FallBack "DIFFUSE"
｝

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[ExecuteInEditMode]
public class TestRenderImage : MonoBehaviour ｛
    public Shader curShader;
    public float grayScaleAmount = 1.0f;
    private Material curMaterial;
    Material material
    ｛
        get
        ｛
            if (curMaterial == null)
            ｛
                curMaterial = new Material(curShader);
                curMaterial.hideFlags = HideFlags.HideAndDontSave;
            ｝
            return curMaterial;
        ｝
    ｝
    void Start()
    ｛
        if (!SystemInfo.supportsImageEffects)
        ｛
            enabled = false;
            return;
        ｝
        if (!curShader && !curShader.isSupported)
        ｛
            enabled = false;
        ｝
    ｝
    void OnRenderImage(RenderTexture sourceTexture, RenderTexture destTexture)
    ｛
        if (curShader != null)
        ｛
            material.SetFloat("_LumionsityAmount", grayScaleAmount);
            Graphics.Blit(sourceTexture, destTexture, material);
        ｝
        else
        ｛
            Graphics.Blit(sourceTexture, destTexture);
        ｝
    ｝
    void Update()
    ｛
        grayScaleAmount = Mathf.Clamp(grayScaleAmount, 0, 1.0f);
    ｝
    void OnDisable()
    ｛
        if (curMaterial)
        ｛
            DestroyImmediate(curMaterial);
        ｝
    ｝
｝