#[derive(Debug)]
pub struct VertexArray
{
    array: gl::types::GLuint,
}

impl VertexArray
{
    pub fn new() -> Self
    {
        let mut array = 0;

        unsafe {
            gl::GenVertexArrays(1, &mut array);
        }

        Self { array }
    }

    pub fn draw(&self, primitive_kind: PrimitiveKind, start_index: u32, index_cnt: u32)
    {
        self.bind();

        unsafe {
            #[allow(clippy::cast_possible_wrap)]
            gl::DrawArrays(
                primitive_kind.into_gl(),
                start_index as gl::types::GLint,
                index_cnt as gl::types::GLsizei,
            );
        }
    }

    pub fn bind(&self)
    {
        unsafe { gl::BindVertexArray(self.array) }
    }
}

impl Drop for VertexArray
{
    fn drop(&mut self)
    {
        unsafe {
            gl::DeleteVertexArrays(1, &self.array);
        }
    }
}

#[derive(Debug)]
pub enum PrimitiveKind
{
    Triangles,
}

impl PrimitiveKind
{
    fn into_gl(self) -> gl::types::GLenum
    {
        match self {
            Self::Triangles => gl::TRIANGLES,
        }
    }
}