终点线

Coddy Godot 游戏：霓虹赛道课程的第 12 课，共 20 课。

跑完三圈，比赛就结束了。state 表示比赛进行到哪一步，race_time 记录整场比赛的时间：

const LAPS := 3
var state := "racing"
var race_time := 0.0

当圈数达到 LAPS 时，比赛结束：状态变为完成，赛车不再响应按键，并显示时间。完成后，比赛不会再进行任何操作：

func finish_race() -> void:
	state = "done"
	car.active = false
	$HUD/Message.text = "Finished!\nTime %s" % clock(race_time)

在 car.gd 中，active 决定是否读取按键。将油门和转向初始值设为 0，并且只在处于活动状态时读取它们：

var throttle := 0.0
var steer := 0.0
if active:
	throttle = Input.get_axis("move_down", "move_up")
	steer = Input.get_axis("move_left", "move_right")

挑战

中等

跑完三圈后，比赛结束。

在 race.gd 中添加上面的代码行，每帧累加 race_time，并以 if state == "done": return 作为 _physics_process 的开头。
编写 finish_race；当 laps >= LAPS 时，finish_lap 会调用它。
在 $HUD/Lap 中显示 "Lap %d/%d" % [mini(laps + 1, LAPS), LAPS]。
在 car.gd 中添加 var active := true，并且只在激活时读取按键。

按下 “开始”，跑完三圈：你的用时就会显示出来。然后点击 “检查”。

亲手试试

extends Node2D

@export var accel := 260.0
@export var max_speed := 200.0
@export var turn_speed := 3.2
@export var drag := 0.6
@export var grip := 7.0

var velocity := Vector2.ZERO
var boost_time := 0.0
var boost_charge := 0.0

@onready var track: Node2D = $"../Track"


func _physics_process(delta: float) -> void:
	var throttle := Input.get_axis("move_down", "move_up")
	var steer := Input.get_axis("move_left", "move_right")
	if Input.is_action_just_pressed("action") and boost_charge >= 1.0:
		boost_charge = 0.0
		boost_time = 1.0
	boost_charge = minf(1.0, boost_charge + delta / 10.0)
	$"../HUD/Boost".scale.x = boost_charge

	var forward := Vector2.RIGHT.rotated(rotation)
	var speed := velocity.dot(forward)
	var top := max_speed
	var grip_now := grip
	if boost_time > 0.0:
		boost_time -= delta
		top = max_speed * 1.3
		velocity += forward * accel * delta
	for pad in get_tree().get_nodes_in_group("boost_pads"):
		if position.distance_to(pad.position) < 22.0:
			boost_time = maxf(boost_time, 0.4)
	for oil in get_tree().get_nodes_in_group("oil"):
		if position.distance_to(oil.position) < 20.0:
			grip_now = grip * 0.12
	if not track.is_on_road(position):
		top = max_speed * 0.45
		velocity *= 1.0 - 2.5 * delta

	if throttle < 0.0 and speed > 10.0:
		velocity += forward * throttle * accel * 1.6 * delta
	else:
		velocity += forward * throttle * accel * delta
	rotation += steer * turn_speed * delta * clampf(absf(speed) / 90.0, 0.0, 1.0) * signf(speed + 0.01)

	var side := forward.orthogonal()
	velocity -= side * velocity.dot(side) * minf(1.0, grip_now * delta)
	velocity *= 1.0 - drag * delta
	if velocity.length() > top:
		velocity = velocity.move_toward(velocity.limit_length(top), accel * 2.0 * delta)
	position += velocity * delta
	$Exhaust.emitting = throttle > 0.0 or boost_time > 0.0
	$Flame.visible = boost_time > 0.0