随机灾难

Coddy Roblox 游戏：灾难生存课程的第 14 课，共 20 课。

如果你已经知道接下来会发生什么，游戏就会变得乏味。每一轮都应该随机选择一种灾难，除非 Settings.Disaster 指定了一种灾难，这在测试新灾难时很方便。

可以用字符串形式的名称查找表中的函数：Disasters["Meteors"] 就是 Disasters.Meteors，所以 Disasters[name](map) 会触发 name 所对应的灾难。如果表中没有这个名称，就会得到 nil，而调用 nil 会导致错误，所以在信任这个设置之前，先检查 Disasters[Settings.Disaster]。

要随机选择，可以列出表中的所有键，再选取一个位置。for name in Disasters do 会按不固定的顺序遍历这些键，因此要先对列表排序：这样，同一个随机数总会选中同一种灾难，让游戏更容易测试。

local names = {}
for name in Disasters do
	table.insert(names, name)
end
table.sort(names)
local pick = names[math.random(1, #names)]

玩家应该知道是什么击中了他们，所以倒计时会显示灾难名称：Flood! Time left: 15。

挑战

中等

每轮随机选择一种灾难。

编写 pickDisaster()：如果 Disasters[Settings.Disaster] 存在，就返回 Settings.Disaster；否则，从表的键排序后得到的列表中随机选择一个名称。
在每轮中：local disaster = pickDisaster()，然后执行 Disasters[disaster](map)。
在倒计时中显示 disaster .. "! Time left: " .. seconds。

按几轮“开始”：状态板会显示每种灾难的名称，例如 Flood! Time left: 15。然后点击“检查”。

亲手试试

local Players = game:GetService("Players")
local ServerStorage = game:GetService("ServerStorage")
local TweenService = game:GetService("TweenService")
local Debris = game:GetService("Debris")
local Settings = require(game.ReplicatedStorage.Settings)

local lobbySpawn = workspace.LobbySpawn

print("Rounds last " .. Settings.RoundLength .. " seconds")

-- 每位玩家的排行榜上都有 Wins
Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player

	local wins = Instance.new("IntValue")
	wins.Name = "Wins"
	wins.Parent = leaderstats
end)

-- 大厅里的状态板
local gui = Instance.new("SurfaceGui")
gui.Parent = workspace.StatusBoard

local status = Instance.new("TextLabel")
status.Name = "Status"
status.Size = UDim2.fromScale(1, 1)
status.BackgroundColor3 = Color3.fromRGB(25, 25, 35)
status.TextColor3 = Color3.fromRGB(255, 255, 255)
status.TextScaled = true
status.Text = "Welcome to Disaster Survival!"
status.Parent = gui

local function setStatus(text)
	status.Text = text
end

local function teleport(player, target)
	local character = player.Character
	if character then
		character:PivotTo(target.CFrame + Vector3.new(0, 4, 0))
	end
end

local function defeat(hit)
	local humanoid = hit.Parent:FindFirstChild("Humanoid")
	if humanoid then
		humanoid.Health = 0
	end
end

-- 按名称列出的灾难
local Disasters = {}

function Disasters.Flood(map)
	local base = map.Base
	local water = Instance.new("Part")
	water.Name = "Water"
	water.Anchored = true
	water.CanCollide = false
	water.Transparency = 0.3
	water.Color = Color3.fromRGB(40, 120, 255)
	water.Size = Vector3.new(base.Size.X + 10, 1, base.Size.Z + 10)
	water.Position = base.Position - Vector3.new(0, 2, 0)
	water.Parent = map
	water.Touched:Connect(defeat)

	local rise = TweenInfo.new(Settings.RoundLength * 0.8, Enum.EasingStyle.Linear)
	TweenService:Create(water, rise, { Position = water.Position + Vector3.new(0, 8, 0) }):Play()
end

function Disasters.Meteors(map)
	local base = map.Base
	task.spawn(function()
		while map.Parent do
			local meteor = Instance.new("Part")
			meteor.Name = "Meteor"
			meteor.Shape = Enum.PartType.Ball
			meteor.Size = Vector3.new(3, 3, 3)
			meteor.Color = Color3.fromRGB(255, 120, 30)
			meteor.Material = Enum.Material.Neon
			local x = base.Position.X + math.random(-15, 15)
			local z = base.Position.Z + math.random(-15, 15)
			meteor.Position = Vector3.new(x, 40, z)
			meteor.Parent = map
			meteor.Touched:Connect(defeat)
			Debris:AddItem(meteor, 4)
			task.wait(0.5)
		end
	end)
end

function Disasters.Shrink(map)
	local base = map.Base
	local shrink = TweenInfo.new(Settings.RoundLength * 0.7, Enum.EasingStyle.Linear)
	TweenService:Create(base, shrink, { Size = Vector3.new(6, base.Size.Y, 6) }):Play()
end

-- 第 14 课：在这里添加随机灾难

-- 回合循环
while true do
	for seconds = Settings.Intermission, 1, -1 do
		setStatus("Intermission: " .. seconds)
		task.wait(1)
	end

	local map = ServerStorage.Maps.Island:Clone()
	map.Name = "Map"
	map.Parent = workspace

	local survivors = {}
	for _, player in Players:GetPlayers() do
		local character = player.Character
		if character and character.Humanoid.Health > 0 then
			teleport(player, map.Spawn)
			survivors[player] = true
			character.Humanoid.Died:Connect(function()
				survivors[player] = nil
			end)
		end
	end

	Disasters.Shrink(map)
	for seconds = Settings.RoundLength, 1, -1 do
		setStatus("Time left: " .. seconds)
		task.wait(1)
	end

	local names = {}
	for player in survivors do
		player.leaderstats.Wins.Value += 1
		teleport(player, lobbySpawn)
		table.insert(names, player.Name)
	end
	map:Destroy()
	if #names > 0 then
		setStatus("Winners: " .. table.concat(names, ", "))
	else
		setStatus("Nobody survived!")
	end
	task.wait(3)
end