Chapter 2: Player Movement

Level 01: Initialize Player

• newly visible classes and methods:
  • Player *
    • initialize
    • readonly game getter/setter
  • Game
    • initializePlayers (use center over position)
    • readonly player left/right getter setter
• Initial state:
  • getter/setter done already
  • rest is empty with comment -> maybe show how to init 1 player, maybe orient from initializeBall
• Explain/Task:
  • Initialize the Player with color, extent and speed 0.
  • initialize Player from Game: set center and addMorph for both players

CodePieces:

• IPTPlayer/initialize

initialize
°°°°°
2
1
°°
	"Please set the color to white, extent to 15x100 and speed to 0"
	super initialize.
°°
	super initialize.
	self 
		color: Color white;
		extent: (15@100);
		stop.

• IPTGame/initializePlayers

initializePlayers
°°°°°
2
1
°°
	"Initialize the left and right player like you did with the ball. For each player, be sure to set the center, and set the game to self."
	| offset | 
	offset := (self extent x / 2 - 30 @ 0).
°°
	| offset | 
	offset := (self extent x / 2 - 30 @ 0).
	self
		playerLeft: (IPTPlayer new
			center: self center - offset;
			game: self);
		playerRight: (IPTPlayer new
			center:  self center + offset;
			game: self);
		addMorph: self playerLeft;
		addMorph: self playerRight.

• IPTPlayer/game

game
°°°°°
2
1
°°
°°
	^ game.

• IPTPlayer/game:

game: aGame
°°°°°
2
1
°°
°°
	game := aGame.

• IPTGame/playerLeft

playerLeft
°°°°°
2
1
°°
°°
	^ playerLeft.

• IPTGame/playerLeft:

playerLeft: aPlayer
°°°°°
2
1
°°
°°
	playerLeft := aPlayer.

• IPTGame/playerRight

playerRight
°°°°°
2
1
°°
°°
	^ playerRight.

• IPTGame/playerRight:

playerRight: aPlayer
°°°°°
2
1
°°
°°
	playerRight := aPlayer.

Level 02: Player Movement

• newly visible classes and methods:
  • Player
    • up / down / stop
    • readonly defaultSpeed
    • readonly speed getter/setter
    • step
    • move (rework complicated statement to clamp)
  • Game
    • readonly initializePlayer -> up
• Initial state:
  • default speed is constant
  • speed getter/setter given
  • initializePlayer sends players up
• Explain/Task:
  • set speed in up/down to default speed (negated) and to 0 in stop
  • move: calc and set new position and clamp to game height - player height
  • step: move with speed

CodePieces:

• IPTPlayer/up

up
°°°°°
2
2
°°
	"Set the speed to negated defaultSpeed."
°°
	self speed: self defaultSpeed negated.

• IPTPlayer/down

down
°°°°°
2
2
°°
	"Set the speed to defaultSpeed."
°°
	self speed: self defaultSpeed.

• IPTPlayer/stop

stop
°°°°°
2
2
°°
	"Set the speed to 0."
°°
	self speed: 0.

• IPTPlayer/defaultSpeed

defaultSpeed
°°°°°
2
2
°°
°°
	^ 10.

• IPTPlayer/speed

speed
°°°°°
2
2
°°
°°
	^ speed.

• IPTPlayer/speed:

speed: aNumber
°°°°°
2
2
°°
°°
	speed := aNumber.

• IPTPlayer/step

step
°°°°°
2
2
°°
	"Call move with the speed."
°°
	self move: self speed.

• IPTPlayer/move

move: aNumber
°°°°°
2
2
°°
	"Add the number to our center. Clamp the new center y component to the game border by using this offset."
	| offset |
	offset := self height * 0.5.
°°
	| offset |
	offset := self height * 0.5.
	self center: self center 
		+ (0 @ (aNumber min: offset max: (self game height - offset))).

• IPTGame/initializePlayers

Level 03: Keyboard input

• newly visible classes and methods:
  • Game
    • (mouseEnter: / Leave:) leave out for now
    • keyUp: / Down:
    • handlesKeyboad:
• Initial state:
  • all empty
• Explain/Task:
  • keyDown: move respective player up/down depending on key
    • left with w/s, right with arrows
    • explain how to get the key e.g. $W, $S, Character arrowUp
    • ifTrue if not explained yet
  • keyUp: stop respective Player
    • use "or" or collection comparison like anySatisfy
    • ifTrue