Shader "URP_Test/PostOutline_3"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags
        {
            "RenderType"="Opaque"
            "RenderPipeline" = "UniversalPipeline"
        }

        Cull Off 
        ZWrite Off 
        ZTest Off

        Pass
        {
            Name "DoMerge"
            // 合并
            HLSLPROGRAM
            #pragma vertex VERT
            #pragma fragment FRAG
            #pragma target 2.0

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

            CBUFFER_START(UnityPerMaterial)

                float4 _MainTex_TexelSize;
                float4 _EdgeTex_TexelSize;

            CBUFFER_END
            
            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);

            TEXTURE2D(_EdgeTex);
            SAMPLER(sampler_EdgeTex);

            struct a2v
            {
                float4 positionOS   : POSITION;
                float2 uv0          : TEXCOORD;
            };

            struct v2f
            {
                float4 positionCS : SV_POSITION;
                float4 texcoord0  : TEXCOORD0;
            };

            v2f VERT(a2v i)
            {
                v2f o;
                o.positionCS = TransformObjectToHClip(i.positionOS.xyz);
                o.texcoord0 = float4(i.uv0, 0, 0);
                return o;
            }

            half4 FRAG(v2f i):SV_TARGET
            {
                half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord0.xy);
                half4 outlineCol = SAMPLE_TEXTURE2D(_EdgeTex, sampler_EdgeTex, i.texcoord0.xy);
                if (outlineCol.a < 0.5) {
                    return col;
                }
                return outlineCol * outlineCol.a + col * (1 - outlineCol.a);
            }

            ENDHLSL
        }
    }
}