// Heptagon shader for Sequence v2
#include "sequence_uniforms"

// Standard v2 post-process layout (bindings 0,1 unused for scene effects)
@group(0) @binding(2) var<uniform> uniforms: UniformsSequenceParams;

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

@vertex fn vs_main(@builtin(vertex_index) vid: u32) -> VertexOutput {
    var out: VertexOutput;
    let x = f32((vid & 1u) << 1u);
    let y = f32((vid & 2u));
    out.position = vec4<f32>(x * 2.0 - 1.0, 1.0 - y * 2.0, 0.0, 1.0);
    out.uv = vec2<f32>(x, y);
    return out;
}

fn sdf_heptagon(p: vec2<f32>, r: f32) -> f32 {
    let an = 3.141593 / 7.0;  // PI/7 for heptagon
    let acs = vec2<f32>(cos(an), sin(an));
    let bn = (atan2(p.x, p.y) % (2.0 * an)) - an;
    let q = length(p) * vec2<f32>(cos(bn), abs(sin(bn)));
    return length(q - r * acs) * sign(q.x - r * acs.x);
}

@fragment fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
    let aspect = uniforms.aspect_ratio;
    let uv = (in.uv * 2.0 - 1.0) * vec2<f32>(aspect, 1.0);

    let rotation = uniforms.beat_time * 0.5;
    let c = cos(rotation);
    let s = sin(rotation);
    let rot_uv = vec2<f32>(
        uv.x * c - uv.y * s,
        uv.x * s + uv.y * c
    );

    let dist = sdf_heptagon(rot_uv, 0.3);
    let color = mix(vec3<f32>(0.2, 0.4, 0.8), vec3<f32>(1.0, 0.8, 0.2),
                    smoothstep(0.01, -0.01, dist));

    return vec4<f32>(color, 1.0);
}