#[macro_use]
extern crate glium;

extern crate glium_sdl2;
extern crate sdl2;

fn main() {
    use glium_sdl2::DisplayBuild;
    use glium::Surface;

    let sdl_context = sdl2::init().unwrap();
    let video_subsystem = sdl_context.video().unwrap();

    let display = video_subsystem.window("Tutorial 01", 800, 600).resizable().build_glium().unwrap();

    #[derive(Copy, Clone)]
    struct Vertex {
        position: [f32; 2],
    }

    implement_vertex!(Vertex, position);

    let vertex1 = Vertex { position: [-0.5, -0.5] };
    let vertex2 = Vertex { position: [ 0.0,  0.5] };
    let vertex3 = Vertex { position: [ 0.5, -0.25] };
    let shape = vec![vertex1, vertex2, vertex3];

    let vertex_buffer = glium::VertexBuffer::new(&display, &shape).unwrap();
    let indices = glium::index::NoIndices(glium::index::PrimitiveType::TrianglesList);

    let vertex_shader_src = r#"
        #version 140

        in vec2 position;

        void main() {
            gl_Position = vec4(position, 0.0, 1.0);
        }
    "#;

    let fragment_shader_src = r#"
        #version 140

        out vec4 color;

        void main() {
            color = vec4(1.0, 0.0, 0.0, 1.0);
        }
    "#;

    let program = glium::Program::from_source(&display, vertex_shader_src, fragment_shader_src, None).unwrap();

    let mut running = true;
    let mut event_pump = sdl_context.event_pump().unwrap();

    while running {
        let mut target = display.draw();
        target.clear_color(0.0, 0.0, 1.0, 1.0);
        target.draw(&vertex_buffer, &indices, &program, &glium::uniforms::EmptyUniforms,
                    &Default::default()).unwrap();
        target.finish().unwrap();

        for event in event_pump.poll_iter() {
            use sdl2::event::Event;

            match event {
                Event::Quit { .. } => running = false,
                _ => ()
            }
        }
    }
}