#![forbid(unsafe_code)]
use std::mem::size_of;
use vulkanalia::vk::{ self, HasBuilder };


pub static VERTICES: [Vertex<f32>; 3] = [
  Vertex::new(Vec2( 0.0, -0.5), Vec3(1.0, 0.0, 0.0)),
  Vertex::new(Vec2( 0.5,  0.5), Vec3(0.0, 1.0, 0.0)),
  Vertex::new(Vec2(-0.5,  0.5), Vec3(0.0, 0.0, 1.0)),
];


#[derive(Clone, Debug)]
pub struct Vec2<T>(T, T);
#[derive(Clone, Debug)]
pub struct Vec3<T>(T, T, T);
#[derive(Clone, Debug)]
#[allow(unused)]
pub struct Vec4<T>(T, T, T, T);


#[repr(C)]
#[derive(Clone, Debug)]
pub struct Vertex<T> {
  pub position: Vec2<T>,
  pub color: Vec3<T>,
}

impl<T> Vertex<T> {
  const fn new(position: Vec2<T>, color: Vec3<T>) -> Self {
    Self { position, color }
  }

  pub fn binding_description() -> vk::VertexInputBindingDescription {
    vk::VertexInputBindingDescription::builder()
        .binding(0)
        .stride(size_of::<Vertex<f32>>() as u32)
        .input_rate(vk::VertexInputRate::VERTEX)
        .build()
  }

  pub fn attribute_descriptions()
      -> [vk::VertexInputAttributeDescription; 2]
  {
    let position = vk::VertexInputAttributeDescription::builder()
                       .binding(0)
                       .location(0)
                       .format(vk::Format::R32G32_SFLOAT)
                       .offset(0)
                       .build();

    let color = vk::VertexInputAttributeDescription::builder()
                       .binding(0)
                       .location(1)
                       .format(vk::Format::R32G32B32_SFLOAT)
                       .offset(size_of::<Vec2<f32>>() as u32)
                       .build();

    [position, color]
  }
}