I made two shader to cutout circle.
It looks like this and works properly:
but I can see the floor or objects behind wall in this case:
I want this image

How can I make it?
Shader of Sphere :
Shader "Unlit/Mask"
{
Properties {}
SubShader
{
Tags
{
"RenderType"="Opaque"
"Queue"="Geometry-1"
}
Stencil
{
Ref 10
Comp Equal
Fail Replace
}
CGPROGRAM
#pragma surface surf nolight noforwardadd nolightmap noambient novertexlights noshadow
struct Input { float4 color:COLOR; };
void surf (Input IN, inout SurfaceOutput o)
{
o.Alpha = 0;
}
float4 Lightingnolight(SurfaceOutput s, float3 lightDir, float atten)
{
return float4(0, 0, 0, 0);
}
ENDCG
}
FallBack ""
}
Shader of Ceiling :
Shader "Unlit/StencilTarget"
{
Properties
{
_Color("Black",Color) =(0,0,0,1)
}
SubShader
{
Pass
{
Tags {
"RenderType"="Opaque"
"Queue"="Geometry"
}
LOD 100
Stencil
{
Ref 10
Comp NotEqual
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _Color;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
return _Color;
}
ENDCG
}
}
}
Shader of Black Ceiling :
Shader "Unlit/StencilTarget"
{
Properties
{
_Color("Black",Color) =(0,0,0,1)
}
SubShader
{
Pass
{
Tags {
"RenderType"="Opaque"
"Queue"="Geometry"
}
LOD 100
Stencil
{
Ref 10
Comp NotEqual
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _Color;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
return _Color;
}
ENDCG
}
}
}