struct VertexInput {
    @builtin(vertex_index) index: u32,
    @location(0) origin: u32,
    @location(1) position: vec3<f32>,
};

struct VertexOutput {
    @builtin(position) clip_position: vec4<f32>,
};

struct CameraUniform {
    view: mat4x4<f32>,
    proj: mat4x4<f32>,
    pos: vec3<f32>,
    scale: f32
};

@group(0) @binding(0)
var<uniform> camera: CameraUniform;

@group(1) @binding(0)
var<storage> origins: array<array<f32,3>>;

const POINT_NORMALS = array<vec2<f32>,4>(
    vec2<f32>(0.0, -0.5),
    vec2<f32>(0.0,  0.5),
    vec2<f32>(0.5, -0.5),
    vec2<f32>(0.5,  0.5)
);

@vertex
fn vs_main(
    model: VertexInput,
) -> VertexOutput {
    var out: VertexOutput;

    let index = model.index % 4u;
    let normal = POINT_NORMALS[index];
    let origin = vec3<f32>(
        origins[model.origin][0],
        origins[model.origin][1],
        origins[model.origin][2]);

    let model_pos = (origin + model.position - camera.pos) * camera.scale;
    let view_proj = camera.proj * camera.view;

    //Scale the world around the camera scale and translate about the camera's
    //absolute (/target) position

    let point_view_pos = view_proj * vec4<f32>(model_pos, 1.0);
    out.clip_position = point_view_pos;
    out.clip_position += vec4<f32>(normal * 0.01, 0.0, 0.0) * point_view_pos.w;

    return out;
}

@fragment
fn fs_main(in: VertexOutput
) -> @location(0) vec4<f32> {
    return vec4<f32>(0.25, 1.0, 0.25, 1.0);
}