Dash on Q

Lesson 7 of 25 in Coddy's Roblox Game: Battlegrounds course.

A dash is a push: setting a root's AssemblyLinearVelocity throws the character. But Roblox lets each player's device run the physics of their own character, so a push the server sets barely moves them. The server decides, and the player's own LocalScript pushes.

The server keeps its abilities in a table, by name, and a yes to a dash goes back to that player's client with FireClient, heard there by OnClientEvent:

remotes.Ability.OnClientEvent:Connect(function(name)
	if name == "Hop" then
		root.AssemblyLinearVelocity = Vector3.new(0, 50, 0)
	end
end)

Challenge

Medium

Make Q dash: the server says yes, your device pushes.

In BattleServer, replace the print with an abilities table: abilities.Dash(player) calls remotes.Ability:FireClient(player, "Dash").
The handler runs abilities[name](player, character, root) when it exists.
In BattleClient, on remotes.Ability.OnClientEvent with "Dash", set your root's velocity to root.CFrame.LookVector * Settings.DashSpeed + Vector3.new(0, 15, 0).

Press Play and press Q: you dash forward. Then Check.

Try it yourself

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

local remotes = game.ReplicatedStorage.Remotes
local lastSwing = {} -- player -> when they last swung

-- Roblox's own sword animations
local slash = Instance.new("Animation")
slash.AnimationId = "rbxassetid://522635514"

print("Swords deal " .. Settings.SwordDamage .. " damage")

-- A swing: the animation, then everyone in the box in front of you is hit
local function swing(player)
	local character = player.Character
	local root = character and character:FindFirstChild("HumanoidRootPart")
	if not root or character.Humanoid.Health <= 0 then
		return
	end
	local now = time()
	if lastSwing[player] and now - lastSwing[player] < Settings.SwingCooldown then
		return
	end
	lastSwing[player] = now
	character.Humanoid.Animator:LoadAnimation(slash):Play()
	-- the box in front of you, never your own body
	local params = OverlapParams.new()
	params.FilterDescendantsInstances = { character }
	local box = root.CFrame * CFrame.new(0, 0, -3)
	local hit = {} -- each humanoid once per swing
	for _, part in workspace:GetPartBoundsInBox(box, Settings.HitboxSize, params) do
		local humanoid = part.Parent:FindFirstChildOfClass("Humanoid")
		if humanoid and not hit[humanoid] then
			hit[humanoid] = true
			humanoid:TakeDamage(Settings.SwordDamage)
			print(humanoid.Parent.Name .. " is at " .. humanoid.Health)
		end
	end
end

-- The client asks for an ability by name
remotes.Ability.OnServerEvent:Connect(function(player, name)
	print(player.Name .. " asked for " .. name)
end)

-- Every player gets a sword every life
Players.PlayerAdded:Connect(function(player)
	player.CharacterAdded:Connect(function()
		local sword = ServerStorage.Sword:Clone()
		sword.Parent = player.Backpack
		sword.Activated:Connect(function()
			swing(player)
		end)
	end)
end)

-- The training dummy: its health bar follows its health, and a beaten
-- dummy comes back after a moment, a fresh copy in the same place
local function setupDummy(dummy)
	local humanoid = dummy.Humanoid
	humanoid.HealthChanged:Connect(function(health)
		dummy.HealthBar.Back.Fill.Size = UDim2.fromScale(health / humanoid.MaxHealth, 1)
	end)
	humanoid.Died:Connect(function()
		local spot = dummy:GetPivot()
		task.wait(0.5)
		dummy:Destroy()
		task.wait(Settings.DummyRespawn)
		local fresh = ServerStorage.Dummy:Clone()
		fresh:PivotTo(spot)
		fresh.Parent = workspace
		setupDummy(fresh)
	end)
end
setupDummy(workspace.Dummy)