Shader "Hidden/FillCrop"
{
	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
	}

	SubShader
	{
		// No culling or depth
		Cull Off ZWrite Off ZTest Always

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "interop_birp.cginc"
            #include "common.hlsl"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
                UNITY_VERTEX_OUTPUT_STEREO
            };

            v2f vert(appdata v)
            {
                v2f o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            UNITY_DECLARE_SCREENSPACE_TEXTURE(_MainTex);
            float4 _CropRegion;

            half4 frag(v2f i) : SV_Target
            {
                UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i)
                float2 uv = CropUV(i.uv, _CropRegion);
                return all(uv == saturate(uv)) ? SAMPLE_SCREEN_TEX(_MainTex, uv) : half4(0, 0, 0, 1);
            }
            ENDCG
        }
    }
}