面片描边shader

Shader "MyURP/Grid_EdgeHighLight"
{
    Properties
    {
        _BaseColor("Base Color", Color) = (1, 1, 1, 1)
        _BaseMap("Base Map", 2D) = "white" {}
        _Thickness("_Thickness", range(0, 10)) = 1
        _AlphaInner("_AlphaInner", range(0, 1)) = 0.1
    }

    SubShader
    {
        Tags
        {
            "RenderPipeline"="UniversalRenderPipeline"
            "RenderType"="Transparent"
            "IgnoreProjector"="True"
            "Queue"="Transparent"
        }


        Pass
        {
            Blend SrcAlpha OneMinusSrcAlpha/*, SrcAlpha One*/
            ZWrite On
            Tags
            {
                "LightMode" = "SRPDefaultUnlit"
            }
            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            // 不加会导致不能合批  就会画三次
            CBUFFER_START(UnityPerMaterial)
            half4 _BaseColor;
            float4 _BaseMap_ST;
            float _Thickness;
            float _AlphaInner;
            CBUFFER_END


            Varyings vert(Attributes IN)
            {
                Varyings o;
                o.uv = IN.uv;
                o.positionHCS = TransformObjectToHClip(IN.positionOS.xyz);
                return o;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                half4 col = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, IN.uv) * _BaseColor;
                col.a = _AlphaInner;
                return col;
            }
            ENDHLSL
        }

        Pass
        {
            Name "Outline"
            Tags
            {
                "LightMode" = "UniversalForward"
            }
            Cull Back
            ZWrite On
            ZTest Less
            Blend SrcAlpha OneMinusSrcAlpha
            ColorMask RGB
            Offset 15,15

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            // 不加会导致不能合批  就会画三次
            CBUFFER_START(UnityPerMaterial)
            half4 _BaseColor;
            float4 _BaseMap_ST;
            float _Thickness;
            CBUFFER_END


            Varyings vert(Attributes IN)
            {
                Varyings o;
                o.uv = IN.uv;

                float3 dir = IN.positionOS.xyz - float3(0, 0, 0);
                dir = TransformObjectToWorldDir(dir);
                float3 worldPos = TransformObjectToWorld(IN.positionOS.xyz);
                worldPos += dir * 2 * _Thickness;

                o.positionHCS = TransformWorldToHClip(worldPos);
                return o;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                half4 col = _BaseColor;
                return col;
            }
            ENDHLSL
        }
    }
}