Eight way movement

Codiga Fan #25880

if direction_key in DIRECTION_TO_FRAME: player_sprite.flip_h = sign(direction.x) == -1

The code describes a physics process where the player's position and velocity are calculated. The code then uses a trick to round down the direction to a 24-character line strip, which is then used to position the player's sprite onscreen. If the direction_key is found in the DIRECTION_TO_FRAME list, the sprite's frame is set to the corresponding value from the list, and the flip_h variable is set to the sign of the direction_key's x value. If the direction_key isn't found in the DIRECTION_TO_FRAME list, the sprite's frame is set to the default value of 0.

extends KinematicBody2D
  # const giong voi var, nhung const ko the bi thay doi/ chinh sua trong code
const SPEED := 700.0
# viet mot cai library de may tinh hieu khi di chuyen nhu the nao se dung` frame nao`
const DIRECTION_TO_FRAME := {
  Vector2.DOWN: 0,
  Vector2.DOWN + Vector2.RIGHT: 1,
  Vector2.RIGHT: 2,
  Vector2.UP + Vector2.RIGHT: 3,
  Vector2.UP: 4,
}
onready var sprite := $Godot

func _physics_process(delta: float) -> void:
  var direction  := Input.get_vector("move_left","move_right","move_up","move_down")
  var velocity := direction *SPEED
  move_and_slide (velocity)
# Round up direction len o line 24 la` vi` trong library da khai bao o tren ko hieu gia' tri float
# cho direction_key.x abs len la` de khi sprite di chuyen ve phia' nguoc lai ( x= gia' tri am),
# sprite se khong dung` frame o trong library tren (library tren ko co gia tri x = so am).
# Thay vao do de sprite di chuyen voi' frame duoc flip,
# thi` se viet mot dieu` kien IF nhu o duoi de sprite flip khi no' di chuyen voi gia tri X = am

  var direction_key := direction.round()
  direction_key.x = abs(direction_key.x)
  
  if direction_key in DIRECTION_TO_FRAME:
  sprite.frame = DIRECTION_TO_FRAME[direction_key]
  # Ham` Sign la` ham` xac dinh. dau' am hay duong cua 1 so'
  # vi'du: sign(6) = 1, sign(-6) = -1, sign(0) =0
  sprite.flip_h = sign(direction.x) == -1  
  # dong` o tren co the hieu nhu sau: 
  # compare if the sign of the value direction.x is 
  # equal to -1. If so, assign the value true to player_sprite.flip_h. 
  # Otherwise, assign the value false to player_sprite.flip_h.