Shader "Unlit/NewUnlitShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _BloomThreshold ("Bloom Threshold", Float) = 0.25
        _BloomIntensity ("Bloom Intensity", Float) = 5.0
        _BlurAmount ("Blur Amount", Float) = 0.01
        _BlurIterations ("Blur Iterations", Int) = 2
        _FisheyeStrength ("Fisheye Strength", Float) = 1.1
        _Resolution ("Resolution", Vector) = (1080, 1920,0,0)
        _OffsetY ("Offset Y", Float) = 0.2
        _FadeAmount ("Fade Amount", Float) = 1.0
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog

            #include "UnityCG.cginc"

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

            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float _BloomThreshold;
            float _BloomIntensity;
            float _BlurAmount;
            int _BlurIterations;
            float _FisheyeStrength;
            float2 _Resolution;
            float _OffsetY;
            float _FadeAmount;

        
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }

            fixed4 blur(float2 uv, sampler2D tex, float blurAmount, int iterations)
            {
                fixed4 color = tex2D(tex, uv);
                // fixed2 offsets[4] = { float2(-blurAmount, 0), float2(blurAmount, 0), float2(0, -blurAmount), float2(0, blurAmount) };
                fixed2 offsets[8]={
                    float2(-blurAmount, 0), float2(blurAmount, 0),
                    float2(0, -blurAmount), float2(0, blurAmount),
                    float2(-blurAmount, -blurAmount), float2(blurAmount, -blurAmount),
                    float2(-blurAmount, blurAmount), float2(blurAmount, blurAmount)
                };
                int len=offsets.Length;
                // fixed2 offsets[4] = { float2(0,-blurAmount), float2(0, blurAmount), float2(0, -blurAmount*2.0), float2(0,blurAmount*2.0) };
 
                int it=min(iterations, 16); // Limit iterations to 4 for performance
                for (int iter = 0; iter < it; iter++)
                {
                    for (int i = 0; i < len; i++)
                    {
                        // Gaussian weights for 8 offsets (approximate)
                        // float weights[8] = {0.1531, 0.1531, 0.1531, 0.1531, 0.0925, 0.0925, 0.0925, 0.0925};
                        // color += tex2D(tex, uv + offsets[i]/_Resolution * (iter + 1)) * weights[i];

                        color += tex2D(tex, uv + offsets[i]/_Resolution * (iter + 1));
                    }
                }
                return color / (1.0 + len*it);
            }

            fixed luminance(fixed4 color) {
                return  0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b; 
            }
            fixed4 bloom(fixed4 col, float threshold, float intensity)
            {
                // fixed4 col = tex2D(tex, uv);
                fixed lum = luminance(col);
                fixed val = clamp(lum - threshold, 0.0, 1.0);

                return col * (val * intensity); // Apply bloom effect by multiplying color with intensity
                // }
            }
           
            float2 fisheyeWarp(float2 uv, float strength)
            {
                float2 center = float2(0.5, 0.5);
                float2 delta = uv - center;
                float dist = length(delta);
                float theta = atan2(delta.y, delta.x);
                float warpedDist = pow(dist, strength);
                float2 warpedDelta = float2(cos(theta), sin(theta)) * warpedDist;
                return center + warpedDelta;
            }
            float2 mirror(float2 uv, float offsety)
            {
                float y= uv.y*_Resolution.y;
                float offset=offsety * _Resolution.y;
                if (y < offset)
                {
                    // return float2(uv.x, 1.0-(offsety-uv.y));
                    return float2(uv.x, (offsety- uv.y)/(_Resolution.x/_Resolution.y));
                }
                else if(y < offset + _Resolution.x)
                {
                   return float2(uv.x, (uv.y-offsety)/(_Resolution.x/_Resolution.y));
                }
                else
                {
                    return float2(uv.x, 1.0-(uv.y- offsety - _Resolution.x/_Resolution.y)/(_Resolution.x/_Resolution.y));                    
                }
                
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                v2f o;
                o.uv=mirror(i.uv, _OffsetY); // Apply mirror effect based on offset
                // o.uv = fisheyeWarp(o.uv, _FisheyeStrength); // Apply fisheye warp effect

                float dist= length(i.uv*_Resolution - float2(0.5, _OffsetY + _Resolution.x/_Resolution.y*0.5)* _Resolution)/_Resolution.x; // Calculate distance from center
                // float dist = length(i.uv.y ); // Calculate distance from center

                dist=pow(1.0 - dist, 2.0); // Square the distance for a smoother fade effect
                
                fixed4 col_raw = tex2D(_MainTex, o.uv);
                fixed4 col_blur = blur(o.uv, _MainTex, _BlurAmount*((1.0-dist)*4.0), _BlurIterations+floor((1.0-dist)*16.0)); // Apply blur with a small amount
                fixed4 col_bloom = bloom(col_blur, _BloomThreshold, _BloomIntensity); // Apply bloom with threshold and intensity

                fixed4 col =  col_blur*col_bloom + col_raw*(dist) + col_blur*(1.0-dist); // Combine raw color with blurred and bloom effects
                
                
                col.rgb = col.rgb * col.a ; // Premultiplied alpha
                col.a*= _FadeAmount; // Apply fade amount to alpha

                // col.r=col.g=col.b= ( dist); // Apply fade effect based on distance from center

                // apply fog
                // UNITY_APPLY_FOG(i.fogCoord, col);
                return col; // Return the final color with bloom effect
            }
            ENDCG
        }
    }
}