use gl_lib::{gl, objects::square, shader};
use failure;


fn main() -> Result<(), failure::Error> {
    // Init sdl to use opengl
    let sdl = sdl2::init().unwrap();
    let video_subsystem = sdl.video().unwrap();

    let gl_attr = video_subsystem.gl_attr();

    gl_attr.set_context_profile(sdl2::video::GLProfile::Core);
    gl_attr.set_context_version(4,5);


    // Create a window that opengl can draw to
    let width = 800;
    let height = 600;

    let viewport = gl::viewport::Viewport::for_window(width as i32, height as i32);

    let window = video_subsystem
        .window("Game", width, height)
        .opengl()
        .resizable()
        .build()?;


    // Load gl functions and set to sdl video subsystem
    let _gl_context = window.gl_create_context().unwrap();
    let gl = gl::Gl::load_with(|s|{
        video_subsystem.gl_get_proc_address(s) as *const std::os::raw::c_void
    });
    viewport.set_used(&gl);

    // Create a default shader
    let shader = shader::Shader::default_shader(&gl)?;

    // and a default square
    let square = square::Square::new(&gl);


    shader.set_used();
    square.render(&gl);

    window.gl_swap_window();

    let size = (height * width *  3) as usize;

    let screenshot_buffer = vec![0.0; size];

    unsafe {
        gl.ReadBuffer(gl::FRONT);
        gl.ReadPixels(0,0,width as i32, height as i32, gl::RGB, gl::FLOAT, screenshot_buffer.as_ptr() as *mut std::os::raw::c_void);
    }

    let mut sum = 0.0;
    for i in 0..size {
        sum += screenshot_buffer[i];
    }

    println!("{:?}", sum);


    Ok(())
}