8.将代码变成类

extends KinematicBody2D
class_name PlantFormPlayer
export var speed = 100.0 # 速度 像素/秒
export var gravity = 6000 # 重力加速度
export var jump_force = 3000.0 # 单次跳跃高度
var velocity = Vector2.ZERO # 速度向量
var dir = Vector2.ZERO # 方向
enum states {
    ON_FLOOR,   # 在地面上
    IN_AIR      # 在空中
}
var _state = states.ON_FLOOR
func _process(delta):
    velocity = Vector2.ZERO
    # 左右移动
    dir.x = Input.get_axis("ui_left","ui_right")
    velocity = dir * speed
    # 实现下落
    velocity.y += gravity * delta
    # 跳跃
    if _state == states.ON_FLOOR and Input.is_action_pressed("ui_accept"):
        velocity.y = -jump_force
        change_state(states.IN_AIR)
    velocity = move_and_slide(velocity,Vector2.UP)
    if is_on_floor():
        change_state(states.ON_FLOOR)
# 更改状态
func change_state(new_state:int):
    _state = new_state
    # 根据不同的状态，进行一些额外配置
    match _state:
        states.IN_AIR:
            pass
        states.ON_FLOOR:
            pass

extends PlantFormPlayer
func _ready():
    pass