Unity ShaderLab特效教程 着色器实例 代码+注释 【可调整贴图的 亮度、对比度、饱和度】_unity调整贴图亮度

如果代码中有什么不清楚请查看以下基础知识

Shader基础知识

unity3d 中 七种坐标知识详解

调整贴图的 亮度、对比度、饱和度的shader

Shader "Custom/duibidu"
{
	Properties
	{
		_MainTex("Albedo (RGB)", 2D) = "white" {}
		_Brightness("Brightness", Float) = 1    //调整亮度
		_Saturation("Saturation", Float) = 1    //调整饱和度
		_Contrast("Contrast", Float) = 1        //调整对比度
	}
		SubShader
		{
			Pass
				{
			ZTest Always
			Cull Off
			ZWrite Off
			Blend SrcAlpha OneMinusSrcAlpha
			CGPROGRAM
			sampler2D _MainTex;
			half _Brightness;
			half _Saturation;
			half _Contrast;

			//vert和frag函数
			#pragma vertex vert
			#pragma fragment frag
			#include "Lighting.cginc"


			struct appdata_t
			{
				float4 vertex : POSITION;
				half4 color : COLOR;
				float2 texcoord : TEXCOORD0;
			};
			//从vertex shader传入pixel shader的参数
			struct v2f
			{
				float4 pos : SV_POSITION; //顶点位置
				half2  uv : TEXCOORD0;    //UV坐标
				half4 color : COLOR;
			};

			//vertex shader
			v2f vert(appdata_t v)
			{
				v2f o;
				//从自身空间转向投影空间
				o.pos = UnityObjectToClipPos(v.vertex);
				o.color = v.color;
				//uv坐标赋值给output
				o.uv = v.texcoord;
				return o;
			}

			//fragment shader
			fixed4 frag(v2f i) : COLOR
			{
				//从_MainTex中根据uv坐标进行采样
				fixed4 renderTex = tex2D(_MainTex, i.uv)*i.color;
				//brigtness亮度直接乘以一个系数，也就是RGB整体缩放，调整亮度
				fixed3 finalColor = renderTex * _Brightness;
				//saturation饱和度：首先根据公式计算同等亮度情况下饱和度最低的值：
				fixed gray = 0.2125 * renderTex.r + 0.7154 * renderTex.g + 0.0721 * renderTex.b;
				fixed3 grayColor = fixed3(gray, gray, gray);
				//根据Saturation在饱和度最低的图像和原图之间差值
				finalColor = lerp(grayColor, finalColor, _Saturation);
				//contrast对比度：首先计算对比度最低的值
				fixed3 avgColor = fixed3(0.5, 0.5, 0.5);
				//根据Contrast在对比度最低的图像和原图之间差值
				finalColor = lerp(avgColor, finalColor, _Contrast);
				//返回结果，alpha通道不变
				return fixed4(finalColor, renderTex.a);
			}
			ENDCG
}
		}
			//防止shader失效的保障措施
			FallBack Off
}

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