@group(0) @binding(0) var smplr: sampler;
@group(0) @binding(1) var txt: texture_2d<f32>;

struct CommonUniforms {
    resolution: vec2<f32>,
    aspect_ratio: f32,
    time: f32,
    beat: f32,
    audio_intensity: f32,
};
struct EffectParams {
    strength: f32,
    _pad: f32,
};

@group(0) @binding(2) var<uniform> common: CommonUniforms;
@group(0) @binding(3) var<uniform> params: EffectParams;

@vertex fn vs_main(@builtin(vertex_index) i: u32) -> @builtin(position) vec4<f32> {
    var pos = array<vec2<f32>, 3>(
        vec2<f32>(-1, -1),
        vec2<f32>(3, -1),
        vec2<f32>(-1, 3)
    );
    return vec4<f32>(pos[i], 0.0, 1.0);
}

@fragment fn fs_main(@builtin(position) p: vec4<f32>) -> @location(0) vec4<f32> {
    let uv = p.xy / common.resolution;
    var res = vec4<f32>(0.0);

    // Parameterized strength + dramatic beat pulsation
    let pulse = 0.5 + common.audio_intensity * 2.0;  // Pulsate between 0.5x and 2.5x with beat
    let size = params.strength * pulse;

    for (var x: f32 = -2.0; x <= 2.0; x += 1.0) {
        for (var y: f32 = -2.0; y <= 2.0; y += 1.0) {
            res += textureSample(txt, smplr, uv + vec2<f32>(x, y) * size / common.resolution.x);
        }
    }
    return res / 25.0;
}