// CaptureTexture 의 알파를 그레이스케일 RGB 로 출력. 알파는 1 고정.
// 검정 = 알파 0, 흰색 = 알파 1
Shader "Hidden/Streamingle/AlphaOnly"
{
    SubShader
    {
        Tags { "RenderType"="Opaque" "RenderPipeline"="UniversalPipeline" }

        Pass
        {
            ZWrite Off ZTest Always Cull Off
            Blend Off

            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.core/Runtime/Utilities/Blit.hlsl"

            half4 Frag(Varyings input) : SV_Target
            {
                half a = SAMPLE_TEXTURE2D(_BlitTexture, sampler_LinearClamp, input.texcoord).a;
                return half4(a, a, a, 1.0);
            }
            ENDHLSL
        }
    }
    Fallback Off
}