Shader "Custom/GlassBlur"
{
    Properties
    {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _BlurSize ("Blur Size", Range(0, 10)) = 1.0
        _Intensity ("Intensity", Range(0, 1)) = 0.5
    }
    
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 200
        
        CGINCLUDE
        #include "UnityCG.cginc"
        
        sampler2D _MainTex;
        float4 _MainTex_TexelSize;
        float _BlurSize;
        float _Intensity;
        
        struct v2f
        {
            float4 pos : SV_POSITION;
            float2 uv : TEXCOORD0;
        };
        
        v2f vert(appdata_img v)
        {
            v2f o;
            o.pos = UnityObjectToClipPos(v.vertex);
            o.uv = v.texcoord;
            return o;
        }
        
        // 高斯模糊函数
        float4 gaussianBlur(v2f i, float2 direction)
        {
            float4 color = float4(0, 0, 0, 0);
            float2 offsets[9] = {
                float2(-1, -1), float2(0, -1), float2(1, -1),
                float2(-1, 0), float2(0, 0), float2(1, 0),
                float2(-1, 1), float2(0, 1), float2(1, 1)
            };
            
            float weights[9] = {
                0.05, 0.1, 0.05,
                0.1, 0.4, 0.1,
                0.05, 0.1, 0.05
            };
            
            for(int j = 0; j < 9; j++)
            {
                float2 uv = i.uv + offsets[j] * _MainTex_TexelSize.xy * _BlurSize * direction;
                color += tex2D(_MainTex, uv) * weights[j];
            }
            
            return color;
        }
        ENDCG
        
        // 水平模糊 Pass
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            float4 frag(v2f i) : SV_Target
            {
                return gaussianBlur(i, float2(1, 0));
            }
            ENDCG
        }
        
        // 垂直模糊 Pass
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            float4 frag(v2f i) : SV_Target
            {
                return gaussianBlur(i, float2(0, 1));
            }
            ENDCG
        }
        
        // 混合 Pass
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            sampler2D _BlurTex;
            
            float4 frag(v2f i) : SV_Target
            {
                float4 original = tex2D(_MainTex, i.uv);
                float4 blurred = tex2D(_BlurTex, i.uv);
                return lerp(original, blurred, _Intensity);
            }
            ENDCG
        }
    }
    FallBack "Diffuse"
}