Shader "GlobalSnow/DepthBlur" {
Properties {
	_MainTex("Buffer (RGBA)", 2D) = "white" {}
}

SubShader {

	CGINCLUDE
	#include "UnityCG.cginc"

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


	struct v2fCross {
	    float4 pos : SV_POSITION;
	    float4 uv: TEXCOORD0;
	    float4 uv1: TEXCOORD1;
	    float4 uv2: TEXCOORD2;
	    float4 uv3: TEXCOORD3;
	    float4 uv4: TEXCOORD4;
	};
	
	sampler2D _MainTex;
	float4 _MainTex_TexelSize;
	
	v2fCross vertBlurH(appdata v) {
    	v2fCross o;
		o.pos = UnityObjectToClipPos(v.vertex);
		#if UNITY_UV_STARTS_AT_TOP
    	if (_MainTex_TexelSize.y < 0) {
	        // Texture is inverted WRT the main texture
    	    v.texcoord.y = 1.0 - v.texcoord.y;
    	}
    	#endif     	
    	o.uv = float4(v.texcoord, 0, 0);
		float4 inc  = float4(_MainTex_TexelSize.x * 1.3846153846, 0, 0, 0);	
    	o.uv1 = float4(v.texcoord - inc, 0, 0);	
    	o.uv2 = float4(v.texcoord + inc, 0, 0);	
		float4 inc2 = float4(_MainTex_TexelSize.x * 3.2307692308, 0, 0, 0);	
    	o.uv3 = float4(v.texcoord - inc2, 0, 0);
    	o.uv4 = float4(v.texcoord + inc2, 0, 0);
		return o;
	}	
	
	v2fCross vertBlurV(appdata v) {
    	v2fCross o;
    	o.pos = UnityObjectToClipPos(v.vertex);
		#if UNITY_UV_STARTS_AT_TOP
    	if (_MainTex_TexelSize.y < 0) {
	        // Texture is inverted WRT the main texture
    	    v.texcoord.y = 1.0 - v.texcoord.y;
    	}
    	#endif 
    	o.uv = float4(v.texcoord, 0, 0);
    	float4 inc  = float4(0, _MainTex_TexelSize.y * 1.3846153846, 0, 0);	
    	o.uv1 = float4(v.texcoord - inc, 0, 0);
    	o.uv2 = float4(v.texcoord + inc, 0, 0);	
    	float4 inc2 = float4(0, _MainTex_TexelSize.y * 3.2307692308, 0, 0);	
    	o.uv3 = float4(v.texcoord - inc2, 0, 0);	
    	o.uv4 = float4(v.texcoord + inc2, 0, 0);
    	return o;
	}

    #define DDEPTH(uv) tex2Dlod(_MainTex,uv).r
    float4 fragBlur (v2fCross i): SV_Target {
        if (i.uv.x<=0.01 || i.uv.x>=0.99 || i.uv.y<=0.01 || i.uv.y>=0.99) return float4(1.0, 0.0, 0.0, 0.0);
        float4 pixel0 = tex2Dlod(_MainTex, i.uv);
        float4 pixel = pixel0.r * 0.2270270270
                    + (DDEPTH(i.uv1) + DDEPTH(i.uv2)) * 0.3162162162
                    + (DDEPTH(i.uv3) + DDEPTH(i.uv4)) * 0.0702702703;
        return float4(pixel.r, pixel0.g, 0, 0);
    }   

	
	ENDCG

	Pass { // Blur horizontally
		CGPROGRAM
		#pragma vertex vertBlurH
		#pragma fragment fragBlur
		#pragma target 3.0
		ENDCG
	}
	
	Pass { // Blur vertically
		CGPROGRAM
		#pragma vertex vertBlurV
		#pragma fragment fragBlur
		#pragma target 3.0
		ENDCG
	}
	
}

Fallback Off
}