halfway through overview of gem catcher

_subsections/sec03/lesson-30.org

@@ -0,0 +1,76 @@
+#+title: Section 03 - Lesson 30 | Section Review
+#+HTML_HEAD: <link rel="stylesheet" type="text/css" href="../../_share/media/css/godot.css" />
+
+* 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