之前的面试的时候有被问到，像4月4号清明节的时候，很多软件的界面都变成灰色，想要实现这个有什么思路，当时由于紧张，没有什么思路，后面想想，用屏幕后处理是可以实现的，像很多游戏，主角死亡后，游戏画面变灰，会不会也是这么实现的呢？话不多说，直接上代码： CS代码： 首先我要准备渲染RenderTexture的材质，这里我们使用一个可以在屏幕后处理中使用的通用基类。
using UnityEngine; using System.Collections; [ExecuteInEditMode] [RequireComponent (typeof(Camera))] public class PostEffectsBase : MonoBehaviour { protected void Start() { CheckResources(); } protected void CheckResources() { bool isSupported = CheckSupport(); if (isSupported == false) { NotSupported(); } } // 检测设备是否支持屏幕特效和渲染纹理 protected bool CheckSupport() { if (SystemInfo.supportsImageEffects == false || SystemInfo.supportsRenderTextures == false) { Debug.LogWarning("This platform does not support image effects or render textures."); return false; } return true; } protected void NotSupported() { enabled = false; } // 创建新的材质去渲染动态纹理 protected Material CheckShaderAndCreateMaterial(Shader shader, Material material) { if (shader == null) { return null; } if (shader.isSupported && material && material.shader == shader) return material; if (!shader.isSupported) { return null; } else { material = new Material(shader); material.hideFlags = HideFlags.HideAndDontSave; if (material) return material; else return null; } } }创建一个我们操作界面变灰的脚本，继承自PostEffectsBase，同时将该脚本挂到摄像机上。
using UnityEngine; using System.Collections; [ExecuteInEditMode] public class SceneGray : PostEffectsBase { //设置渲染的shader public Shader curShader; //灰度程度0~1，0为原来颜色，1为灰色 public float grayScaleAmount = 1.0f; //新创建的材质 private Material curMaterial; Material material { get { if (curMaterial == null) { curMaterial = CheckShaderAndCreateMaterial(curShader,curMaterial); } return curMaterial; } } //屏幕后处理函数，设置shader参数 void OnRenderImage(RenderTexture sourceTexture, RenderTexture destTexture) { if (curShader != null) { material.SetFloat("_LuminosityAmount", grayScaleAmount); Graphics.Blit(sourceTexture, destTexture, material); } else { Graphics.Blit(sourceTexture, destTexture); } } //设置灰度程度 void Update() { grayScaleAmount = Mathf.Clamp(grayScaleAmount, 0, 1.0f); } //删除新建的材质 void OnDisable() { if (curMaterial) { DestroyImmediate(curMaterial); } } }shader代码：
Shader "Custom/GrayColor" { Properties { _MainTex ("Base (RGB)", 2D) = "white" {} _grayScale("_grayScale",Float) = 1.0 } SubShader { Pass { ZTest Always Cull Off ZWrite Off CGPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" sampler2D _MainTex; half _grayScale; struct v2f { float4 pos : SV_POSITION; half2 uv: TEXCOORD0; }; v2f vert(appdata_img v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); o.uv = v.texcoord; return o; } fixed4 frag(v2f i) : SV_Target { fixed4 renderTex = tex2D(_MainTex, i.uv); //置灰后的灰色值 float gray = dot(renderTex.rgb, float3(0.299, 0.587, 0.114)); fixed4 grayColor = fixed4(gray, gray, gray,renderTex.a); //将原来的颜色与灰色做插值运算 fixed4 finalColor = lerp(renderTex,grayColor,_grayScale); return finalColor; } ENDCG } } Fallback Off }最终效果：
GrayScaleAmount=0.png GrayScaleAmount=1.png
