Shader "Hidden/BrokenGlassEffect"
{
    Properties
    {
        _MainTex ("Main Texture", 2D) = "white" {}
        _MainTex2 ("Glass Texture", 2D) = "white" {}
        _Value ("Distortion Strength", Float) = 1.0
        _Bullet_1 ("Bullet 1", Float) = 1.0
        _Bullet_2 ("Bullet 2", Float) = 1.0
        _Bullet_3 ("Bullet 3", Float) = 1.0
        _Bullet_4 ("Bullet 4", Float) = 1.0
        _Bullet_5 ("Bullet 5", Float) = 1.0
        _Bullet_6 ("Bullet 6", Float) = 1.0
        _Bullet_7 ("Bullet 7", Float) = 1.0
        _Bullet_8 ("Bullet 8", Float) = 1.0
        _Bullet_9 ("Bullet 9", Float) = 1.0
        _Bullet_10 ("Bullet 10", Float) = 1.0
        _Bullet_11 ("Bullet 11", Float) = 1.0
        _Bullet_12 ("Bullet 12", Float) = 1.0
    }

    SubShader
    {
        Tags { "RenderType"="Opaque" "RenderPipeline" = "UniversalPipeline" }
        LOD 100

        Pass
        {
            Name "BrokenGlassEffect"
            ZTest Always Cull Off ZWrite Off

            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            sampler2D _MainTex;
            sampler2D _MainTex2;
            float4 _MainTex_TexelSize;

            float _Value;
            float _Bullet_1;
            float _Bullet_2;
            float _Bullet_3;
            float _Bullet_4;
            float _Bullet_5;
            float _Bullet_6;
            float _Bullet_7;
            float _Bullet_8;
            float _Bullet_9;
            float _Bullet_10;
            float _Bullet_11;
            float _Bullet_12;

            Varyings Vert(Attributes input)
            {
                Varyings output;
                output.positionHCS = TransformObjectToHClip(input.positionOS.xyz);
                output.uv = input.uv;
                return output;
            }

            half4 Frag(Varyings i) : SV_Target
            {
                float2 uv = i.uv;
                float2 uv2 = uv;

                #if UNITY_UV_STARTS_AT_TOP
                if (_MainTex_TexelSize.y < 0)
                    uv.y = 1-uv.y;
                #endif

                uv /= 2;
                float col = 0;

                // Red channel sampling
                col = (tex2D(_MainTex2, uv).rgb * _Bullet_1).r;
                uv += float2(0.5, 0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_2).r;
                uv += float2(0, 0.5);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_3).r;
                uv -= float2(0.5, 0.0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_4).r;

                // Green channel sampling
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_5).g;
                uv += float2(0.5, 0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_6).g;
                uv += float2(0, 0.5);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_7).g;
                uv -= float2(0.5, 0.0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_8).g;

                // Blue channel sampling
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_9).b;
                uv += float2(0.5, 0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_10).b;
                uv += float2(0, 0.5);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_11).b;
                uv -= float2(0.5, 0.0);
                col += (tex2D(_MainTex2, uv).rgb * _Bullet_12).b;

                uv2 += float2(col, col) / 4;

                float3 col2 = tex2D(_MainTex, uv2).rgb;
                float c = col;
                col2 = col2 + float3(c, c, c);

                return float4(col2, 1.0);
            }
            ENDHLSL
        }
    }
}