Shader入门精要笔记-屏幕后处理（2）

目录

一.调整屏幕的亮度、饱和度和对比度

准备：1.去除场景中的天空盒子

2.新建一个脚本（BrightnessSaturationAndContrast.cs）挂载到摄像机上

3.新建一个Shader（BrightnessSaturationAndContrast.cs）

4.在创建中放置一个 Quad，将准备好的图片拖到Quad上

5.将Shader（BrightnessSaturationAndContrast.cs）代码挂载到BrightnessSaturationAndContrast.cs）脚本参数上并可在面板中设置shader的参数

 6.效果展示

一.调整屏幕的亮度、饱和度和对比度

准备：1.去除场景中的天空盒子

2.新建一个脚本（BrightnessSaturationAndContrast.cs）挂载到摄像机上

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
 
public class BrightnessSaturationAndContrast : PostEffectsBase
{
    public Shader briSatConShader;
 
    private Material briSatConMaterial;
 
    public Material material
    {
        get
        {
            briSatConMaterial = CheckShaderAndCreateMaterial(briSatConShader, briSatConMaterial);
            return briSatConMaterial;
        }
    }
 
    // 调整亮度
    [Range(0.0f, 3.0f)] public float brightness = 1.0f;
 
    //调整饱和度
    [Range(0.0f, 3.0f)] public float saturation = 1.0f;
 
    //调整对比度
    [Range(0.0f, 3.0f)] public float contrast = 1.0f;
 
    void OnRenderImage(RenderTexture src, RenderTexture dest)
    {
        if (material!=null)
        {
            //把修改的材质的参数传递给材质
            material.SetFloat("_Brightness",brightness);
            material.SetFloat("_Saturation",saturation);
            material.SetFloat("_Contrast",contrast);
            //对材质进行处理
            Graphics.Blit(src,dest,material);
        }
        else
        {
            Graphics.Blit(src,dest);
        }
    }
}

3.新建一个Shader（BrightnessSaturationAndContrast.cs）

Shader "Unlit/Chapter12-BrightnessSaturationAndContrast"
{
    Properties
    {
        _MainTex("Base(RGB)",2D)="white"{}
        _Brightness("Brightness",Float)=1
        _Saturation("Saturation",Float)=1
        _Contrast("Contrast",Float)=1
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100
 
        Pass
        {
            ZTest Always Cull Off ZWrite Off
 
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog
 
            #include "UnityCG.cginc"
 
 
            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 pos : SV_POSITION;
            };
 
            sampler2D _MainTex;
            half _Brightness;
            half _Saturation;
            half _Contrast;
 
            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);
                //_Brightness调整亮度
                fixed3 finalColor=renderTex.rgb*_Brightness;
                 //计算亮度值
                fixed luminance=0.2125*renderTex.r+0.7154*renderTex.g+0.0721*renderTex.b;
                fixed3 luminanceColor=fixed3(luminance,luminance,luminance);
                //计算饱和度颜色
                finalColor=lerp(luminanceColor,finalColor,_Saturation);
                //对比度
                fixed3 avgColor=fixed3(0.5,0.5,0.5);
                finalColor=lerp(avgColor,finalColor,_Contrast);
                return fixed4(finalColor,renderTex.a);
            }
            ENDCG
        }
    }
    Fallback Off
}

4.在创建中放置一个 Quad，将准备好的图片拖到Quad上

5.将Shader（BrightnessSaturationAndContrast.cs）代码挂载到BrightnessSaturationAndContrast.cs）脚本参数上并可在面板中设置shader的参数

 6.效果展示

原图