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

struct Uniforms {
    time: f32,
    beat: f32,
    intensity: f32,
    aspect_ratio: f32,
    resolution: vec2<f32>,
};

@group(0) @binding(2) var<uniform> uniforms: Uniforms;

@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 / uniforms.resolution;
    let off = 0.02 * uniforms.intensity;
    let r = textureSample(txt, smplr, uv + vec2<f32>(off, 0.0)).r;
    let g = textureSample(txt, smplr, uv).g;
    let b = textureSample(txt, smplr, uv - vec2<f32>(off, 0.0)).b;
    return vec4<f32>(r, g, b, 1.0);
}