let mut chip8_keys = [false; 16];

        for key in keys {
            let index = match key {
                Keycode::Num1 => Some(0x1),
                Keycode::Num2 => Some(0x2),
                Keycode::Num3 => Some(0x3),
                Keycode::Num4 => Some(0xc),
                Keycode::Q    => Some(0x4),
                Keycode::W    => Some(0x5),
                Keycode::E    => Some(0x6),
                Keycode::R    => Some(0xd),
                Keycode::A    => Some(0x7),
                Keycode::S    => Some(0x8),
                Keycode::D    => Some(0x9),
                Keycode::F    => Some(0xe),
                Keycode::Z    => Some(0xa),
                Keycode::X    => Some(0x0),
                Keycode::C    => Some(0xb),
                Keycode::V    => Some(0xf),
                _             => None,
            };

            if let Some(i) = index {
                chip8_keys[i] = true;
            }