finished review

_subsections/sec03/lesson-30.org

@@ -74,3 +74,85 @@ queue_free()
 #+end_src
 
 ** Game scene
+*** preload assets
+- using const to set builtin preload function
+ #+begin_src gdscript
+  const EXPLOSDE = preload("res://assets/explode.wav")
+ #+end_src
+
+*** add a PackedScene variable
+  - allows us to instantiate gem scenes
+  - export allows us to drag and drop the scene we want into the inspector
+      #+begin_src gdscript
+      @export var gem_scene: PackedScene
+
+	      # when time comes to use it
+	      gem_scene.instantiate()
+	      add_child(gem_scene)
+      #+end_src
+
+  - otherwise we would have to preload it
+      #+begin_src gdscript
+	      gem_scene = preload("res://somescene.tscn").instantiate()
+	      add_child(gem_scene)
+      #+end_src
+
+*** use onready to add nodes in tree scene
+#+begin_src gdscript
+@onready var label: Label = $Label
+@onready var timer: Timer = $Timer
+@onready var audio_stream_player_2d: AudioStreamPlayer2D = $AudioStreamPlayer2D
+#+end_src
+
+- these are all scenes in the Game tree
+- use onready to attach them to variables for use in game script
+- onready makes sure it's available so we dont end up with a null reference
+
+*** spawn gem at _ready
+- in the ready function immediately call spawn_gem
+- spawn Gem instantiates a gem scene and type casts it to a Gem class
+- connect any signals
+- set it's position
+- add it as a child
+  #+begin_src gdscript
+  var new_gem: Gem = gem_scene.instantiate()
+  new_gem.on_gem_off_screen.connect(game_over)
+  new_gem.position = Vector2(xpos, ypos)
+  add_child(new_gem)
+  #+end_src
+
+*** stop all function
+- stop the timer
+- run through all children and set process to false
+  #+begin_src gdscript
+  timer.stop()
+  for child in get_children():
+	  child.set_process(false)
+  #+end_src
+
+*** turn off audio
+- get references to audio and call 'stop' function
+- you can also set another sound for ending and play that
+
+#+begin_src gdscript
+ audio_stream_player_2d.stop()
+ audio_stream_player_2d.stream = EXPLODE
+ audio_stream_player_2d.play()
+#+end_src
+
+*** whenever timer times out spawn a gem
+- we attached the timer to a signal to call a function that calls spawn gem
+
+*** when the paddle gets hit by a gem
+- increase score
+- set the position of where the paddle got hit to the audio and play a sound
+- free up the hit object (the gem)
+
+#+begin_src gdscript
+func _on_padd_area_entered(area: Area2D) -> void:
+	_score += 1
+	label.text = "%05d" % _score
+	audio_stream_player_2d.position = area.position
+	audio_stream_player_2d.play()
+	area.queue_free()
+#+end_src