Tetris

Okay, we're now ready to start writing down our tetris!

First, let's fulfill our main.rs file in order to check whether everything is working as expected:

    extern crate sdl2;

    use sdl2::pixels::Color;
    use sdl2::event::Event;
    use sdl2::keyboard::Keycode;
    use std::time::Duration;
    use std::thread::sleep;

    pub fn main() {
      let sdl_context = sdl2::init().expect("SDL initialization   
      failed");
      let video_subsystem = sdl_context.video().expect("Couldn't get 
       SDL video subsystem");

      let window = video_subsystem.window("rust-sdl2 demo: Video", 800,
            600)
        .position_centered()
        .opengl()
        .build()
        .expect("Failed to create window");

      let mut canvas = window.into_canvas().build().expect("Failed to
        convert window into canvas");

      canvas.set_draw_color(Color::RGB(255, 0, 0));
      canvas.clear();
      canvas.present();
      let mut event_pump = sdl_context.event_pump().expect("Failed to
        get SDL event pump");

      'running: loop {
         for event in event_pump.poll_iter() {
            match event {
              Event::Quit { .. } |
              Event::KeyDown { keycode: Some(Keycode::Escape), .. } =>  
              {
                break 'running
              },
              _ => {}
            }
         }
         sleep(Duration::new(0, 1_000_000_000u32 / 60));
      }
    }

You'll note the following line:

    ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));

It allows you to avoid using all your computer CPU time needlessly and only rendering 60 times every second at most.

Now run the following in your terminal:

$ cargo run

If you have a window filled with red (just as shown in the following screenshot), then everything's fine!

Figure 2.4