Shader "ColorBleedShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        
        [Header(Red)]
        _RedX ("Offset X", Range(-0.5, 0.5)) = 0.0025
        _RedY ("Offset Y", Range(-0.5, 0.5)) = 0.0
        
        [Header(Green)]
        _GreenX ("Offset X", Range(-0.5, 0.5)) = 0.0
        _GreenY ("Offset Y", Range(-0.5, 0.5)) = 0.0
        
        [Header(Blue)]
        _BlueX ("Offset X", Range(-0.5, 0.5)) = -0.0025
        _BlueY ("Offset Y", Range(-0.5, 0.5)) = 0.0
    }
    SubShader
    {	Stencil 
        {
            Ref 0
            Comp Equal
        }
        
        Pass
        {
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            
            #include "UnityCG.cginc"

            sampler2D _MainTex;
            float _RedX = 0.0025;
            float _RedY;
            float _GreenX = 0.0;
            float _GreenY;
            float _BlueX = -0.0025;
            float _BlueY;
            
            fixed4 frag (v2f_img i) : SV_Target
            {
                fixed4 col = fixed4(1, 1, 1, 0);
                
                float2 red_uv = i.uv + float2(_RedX, _RedY);
                float2 green_uv = i.uv + float2(_GreenX, _GreenY);
                float2 blue_uv = i.uv + float2(_BlueX, _BlueY);
                
                col.r = tex2D(_MainTex, red_uv).r;
                col.g = tex2D(_MainTex, green_uv).g;
                col.b = tex2D(_MainTex, blue_uv).b;
                col.a = max(max(col.a, col.a), col.a);
                
                return col;
            }
            ENDCG
        }
    }
}