Shader "SGG/Special/DepthPaste"

Shader "SGG/Special/DepthPaste"
{
	Properties{
			_MainCamDepthTex("Texture", 2D) = "white" {}
			[HideInInspector] _MainTex("Texture", 2D) = "white" {}
	}

	SubShader{
		// markers that specify that we don't need culling
		// or comparing/writing to the depth buffer
		Cull Off
		ZWrite Off
		ZTest Always

		Pass{
			CGPROGRAM
			//include useful shader functions
			#include "UnityCG.cginc"

			//define vertex and fragment shader
			#pragma vertex vert
			#pragma fragment frag

			sampler2D _MainTex;
			sampler2D _MainCamDepthTex;
			sampler2D _CameraDepthTexture;


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

			struct v2f {
				float4 position : SV_POSITION;
				float2 uv : TEXCOORD0;
			};

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

			fixed4 frag(v2f i) : SV_TARGET{
				fixed4 col = tex2D(_MainTex, i.uv);
				float depth0 = tex2D(_MainCamDepthTex, i.uv).r;
				float depth = tex2D(_CameraDepthTexture, i.uv).r;
				if (depth < depth0)
					col.a = 0;
				return col;
			}
			ENDCG
		}
	}
}