@group(0) @binding(0) var sky_tex: texture_2d<f32>;
@group(0) @binding(1) var sky_sampler: sampler;
@group(0) @binding(2) var<uniform> globals: GlobalUniforms;

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

@vertex
fn vs_main(@builtin(vertex_index) vertex_index: u32) -> VertexOutput {
    var pos = array<vec2<f32>, 3>(
        vec2<f32>(-1.0, -1.0),
        vec2<f32>( 3.0, -1.0),
        vec2<f32>(-1.0,  3.0)
    );
    
    var out: VertexOutput;
    out.position = vec4<f32>(pos[vertex_index], 0.0, 1.0);
    out.uv = vec2<f32>(pos[vertex_index].x * 0.5 + 0.5, 1.0 - (pos[vertex_index].y * 0.5 + 0.5));
    return out;
}

@fragment
fn fs_main(@builtin(position) frag_pos: vec4<f32>) -> @location(0) vec4<f32> {
    return textureSample(sky_tex, sky_sampler, frag_pos.xy / globals.resolution);
}