#+title: Section 03 - Lesson 30 | Section Review
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* Links
- [[../../toc.org][TOC - Godot Notes]]
- [[https://www.udemy.com/course/jumpstart-to-2d-game-development-godot-4-for-beginners/learn/lecture/45070537#overview][S03:L42.30 - Section Review]]

* Notes

** paddle scene
*** node composition
- root: Area2D
- Sprite2D
- CollisionShape2D

*** script view: paddle.gd
- extends Area2D

**** use *@export* to create speed variable
  - can be modified in Inspector
  - give default value

**** override _process function
  - check if =Input.is_action_pressed=
    - is 'left'
    - is 'right'

  - move paddle
    - get the Node2D.position property
      - multiply speed by delta and add or subtract it from position.x
      - delta is number of seconds that elapsed since the previous frame

** gem scene
*** node composition
- root: Area2D
- Sprite2D
- CollisionShape2D

*** script view: gem.gd
- extends Area2D

**** set class name
- =class_name Gem=
- this allows us to instantiate Gem objects in scripts

**** set a signal property
- =signal on_gem_off_screen=
- allows us to attach listeners who will be notified when we emit a signal

**** set export property
- =@export var speed=
- lets us set the speed in the Inspector

*** modify _process
**** determine if the gem has gone out of bounds
- this is going to be the edge of the viewport
- check position property against the viewport rect property
  #+begin_src gdscript
  if position.y > get_viewport_rect().size.y
  #+end_src

**** if gem went out of bounds
***** emit signal
#+begin_src gdscript
on_gem_off_screen.emit()
#+end_src

***** stop the gem and remove it from the node tree
- stop going through the process function
- delete node at the end of the current frame
#+begin_src gdscript
set_process(false)
queue_free()
#+end_src

** Game scene