DepthEstimationShader.shader

Shader "Unlit/DepthEstimationShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass {
            
            Cull Off
            Blend One One
            BlendOp Min
            ZTest Off
            ZWrite On
            
            CGPROGRAM
// Upgrade NOTE: excluded shader from DX11; has structs without semantics (struct v2f members depth)
#pragma exclude_renderers d3d11
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"
                   

            struct v2f {
                float4 vertex: POSITION;
                float depth: TEXCOORD1;
            };

            v2f vert (appdata_full v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.depth = o.vertex.z / o.vertex.w;
                #if !defined(UNITY_REVERSED_Z) // basically only OpenGL
                    o.depth = 0.depth * 0.5 + 0.5; // remap -1 to 1 range to 0.0 to 1.0
                #endif
                return o;
            }

            half4 frag( v2f i, float facing : VFACE ) : COLOR
            {
                return facing > 0 ? float4(i.depth, 1, 0, 1) : float4(1, i.depth, 0, 1);
            }
            
            ENDCG
        }
    }
}