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前言

我们使用之前的棋盘格作为测试Shader来添加雾效。

• Unity中 URP 下的棋盘格Shader

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一、URP下Shader支持雾效的步骤

1、添加雾效变体

#pragma multi_compile_fog

2、在Varying结构体中添加雾效因子

float fogCoord : TEXCOORD2;

3、在顶点着色器中，我们使用内置函数得到雾效因子

o.fogCoord = ComputeFogFactor(o.vertexCS.z);

4、在片元着色器中，把输出颜色 和 雾效因子混合输出

col.rgb = MixFog(col,i.fogCoord);

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二、在Unity中打开雾效

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三、测试代码

Shader "MyShader/URP/P3_8"
{Properties{_Repeat("Repeat",Float) = 0_Color("Color",Color) = (1,1,1,1)}SubShader{Tags{"PenderPipeline"="UniversalPipeline""RenderType"="Opaque""Queue"="Geometry"}Cull FrontPass{HLSLPROGRAM#pragma vertex vert#pragma fragment frag#pragma multi_compile_fog#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"struct Attribute{float3 vertexOS : POSITION;float2 uv : TEXCOORD0;};struct Varying{float3 vertexOS : TEXCOORD0;float4 vertexCS : SV_POSITION;float2 uv : TEXCOORD1;float fogCoord : TEXCOORD2;};CBUFFER_START(UnityPerMaterial)float _Repeat;float4 _Color;CBUFFER_ENDVarying vert(Attribute v){Varying o;o.vertexOS = v.vertexOS;o.vertexCS = TransformObjectToHClip(v.vertexOS);o.uv = v.uv * _Repeat;o.fogCoord = ComputeFogFactor(o.vertexCS.z);return o;}half4 frag(Varying i) : SV_Target{/*half4 col1;half4 col2;if(i.uv.x < 0.5)col1 = 0;elsecol1 = 0.5;if(i.uv.y < 0.5)col2 = 0;elsecol2 = 0.5;*/half4 col;float2 uv = floor(i.uv * 2) * 0.5;col = frac(uv.x + uv.y) * 2;float mask = i.vertexOS.y;col = col * _Color + mask;col.rgb = MixFog(col,i.fogCoord);return col;}ENDHLSL}}SubShader{Tags{"RenderType"="Opaque""Queue"="Geometry"}Cull FrontPass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"struct appdata{float3 vertexOS : POSITION;float2 uv : TEXCOORD0;};struct v2f{float3 vertexOS : TEXCOORD0;float4 vertexCS : SV_POSITION;float2 uv : TEXCOORD1;};float _Repeat;float4 _Color;v2f vert(appdata v){v2f o;o.vertexOS = v.vertexOS;o.vertexCS = UnityObjectToClipPos(v.vertexOS);o.uv = v.uv * _Repeat;return o;}half4 frag(v2f i) : SV_Target{half4 col;float2 uv = floor(i.uv * 2) * 0.5;col = frac(uv.x + uv.y) * 2;float mask = i.vertexOS.y;col = col * _Color + mask;return col;}ENDCG}}
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