@group(0) @binding(0)
var mySampler : sampler;

@group(0) @binding(1)
var myTexture : texture_2d<f32>;

@group(0) @binding(2)
var<uniform> resolution : vec2<f32>;

struct VertexOutput {
    @builtin(position) position : vec4<f32>,
    @location(0) uv : vec2<f32>,
};

@vertex
fn vertexMain(@location(0) position : vec3<f32>, @location(1) uv : vec2<f32>) -> VertexOutput {
    var out : VertexOutput;
    out.position = vec4<f32>(position, 1.0);
    out.uv = uv;
    return out;
}

@fragment
fn fragmentMain(@location(0) uv : vec2<f32>) -> @location(0) vec4<f32> {
    let texelSize = 1.0 / resolution;
    
    // Sample surrounding pixels
    let colorCenter = textureSample(myTexture, mySampler, uv);
    let colorN = textureSample(myTexture, mySampler, uv + vec2<f32>(0.0, texelSize.y));
    let colorS = textureSample(myTexture, mySampler, uv - vec2<f32>(0.0, texelSize.y));
    let colorE = textureSample(myTexture, mySampler, uv + vec2<f32>(texelSize.x, 0.0));
    let colorW = textureSample(myTexture, mySampler, uv - vec2<f32>(texelSize.x, 0.0));

    let luma = dot(colorCenter.rgb, vec3<f32>(0.299, 0.587, 0.114));
    let lumaN = dot(colorN.rgb, vec3<f32>(0.299, 0.587, 0.114));
    let lumaS = dot(colorS.rgb, vec3<f32>(0.299, 0.587, 0.114));
    let lumaE = dot(colorE.rgb, vec3<f32>(0.299, 0.587, 0.114));
    let lumaW = dot(colorW.rgb, vec3<f32>(0.299, 0.587, 0.114));

    let edgeH = abs(lumaW - lumaE);
    let edgeV = abs(lumaN - lumaS);
    let edge = max(edgeH, edgeV);

    let threshold = 0.1;

    if (edge < threshold) {
        return colorCenter; // No edge — return original
    }

    // Basic blur
    let blur = (colorN + colorS + colorE + colorW) * 0.25;
    return vec4<f32>(blur.rgb, 1.0);
}