Using texture 2d array in a fragment shader

Unity Engine
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1

I found a tutorial that does this in a surface shader but I want to learn how to do it in a fragment shader.

I’m creating some meshes procedurally and combining them into one and I am setting the “slice” in the texture 2D array as the Z in the UVs like so.

Vector3[] uv = new Vector3[] { new(0,0,3), new(0,1,3), new(1,1,3), new(1,0,3) };

So in the above there the 3 is the slice I want to use for that mesh.

And in my shader I’m not really sure how to use that.

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

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

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

            v2f vert(appdata d) 
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(d.vertex);
                o.uv = d.uv;
                return o;
            }

            UNITY_DECLARE_TEX2DARRAY(_Texture);

            fixed4 frag(v2f i) : SV_Target
            {
                return UNITY_SAMPLE_TEX2DARRAY(_Texture, i.uv);
            }

            ENDCG

Here is an example of how to do it in a surface shader.

CGPROGRAM
#pragma surface surf Standard vertex:vert
UNITY_DECLARE_TEX2DARRAY(_Tx);

struct Input
{
    float2 uv_MainTex;
    float arrayIndex;
};

void vert(inout appdata_full v, out Input o)
{
    o.uv_MainTex = v.texcoord.xy;
    o.arrayIndex = v.texcoord.z;
}

void surf(Input IN, inout SurfaceOutputStandard o)
{
    fixed4 c = UNITY_SAMPLE_TEX2DARRAY(_Texture, float3(IN.uv_MainTex, IN.arrayIndex));
    o.Albedo = c.rgb;
}
ENDCG