Combat System

This example shows a simple combat system using Reheaven.

The server owns the real combat state.

The client reacts to that state and updates the UI.

Key Point

Combat actions change state. The UI reacts automatically.

Combat State

Combat-related values naturally belong together.

CombatState.lua

local combatState, setCombatState = Reheaven.signal({
    health = 100;
    maxHealth = 100;

    blocking = false;
    stunned = false;
    combo = 0;
})

Other values can be derived automatically.

CombatDerived.lua

local computed = Reheaven.computed

local alive = computed(function()
    return combatState().health > 0
end)

local healthPercent = computed(function()
    local state = combatState()

    return state.health / state.maxHealth
end)

local canAct = computed(function()
    local state = combatState()

    return state.health > 0 and not state.stunned
end)

Combat Actions

Actions describe how combat state changes.

CombatActions.lua

local function damage(amount)
    if not alive() then
        return
    end

    local current = combatState()
    local nextState = table.clone(current)

    if nextState.blocking then
        amount *= 0.5
    end

    nextState.health = math.max(nextState.health - amount, 0)

    setCombatState(nextState)
end

local function heal(amount)
    local current = combatState()
    local nextState = table.clone(current)

    nextState.health = math.min(nextState.health + amount, nextState.maxHealth)

    setCombatState(nextState)
end

local function setBlockState(value)
    local current = combatState()
    local nextState = table.clone(current)

    nextState.blocking = value

    setCombatState(nextState)
end

Table State

combatState is a table signal, so the examples clone the current table before changing it.

This keeps updates explicit:

local current = combatState()
local nextState = table.clone(current)

nextState.health -= 10

setCombatState(nextState)

This combat state is flat, so table.clone is enough.

If the state had nested tables, you would need to clone those nested tables too, or use a deepClone helper.

Stunning

Stun state can temporarily prevent actions.

CombatStun.lua

local function stun(duration)
    local current = combatState()
    local nextState = table.clone(current)

    nextState.stunned = true
    nextState.blocking = false

    setCombatState(nextState)

    task.delay(duration, function()
        local latest = combatState()
        local afterStun = table.clone(latest)

        afterStun.stunned = false

        setCombatState(afterStun)
    end)
end

Combo Counter

A combo can increase with each hit and reset after the third hit.

CombatCombo.lua

local function registerHit()
    if not canAct() then
        return
    end

    local current = combatState()
    local nextState = table.clone(current)

    nextState.combo += 1

    if nextState.combo >= 3 then
        nextState.combo = 0
        nextState.stunned = true
    end

    setCombatState(nextState)

    if nextState.stunned then
        task.delay(1, function()
            local latest = combatState()
            local afterStun = table.clone(latest)

            afterStun.stunned = false

            setCombatState(afterStun)
        end)
    end
end

Server Validation

The client can request actions.

The server decides whether those actions are valid.

CombatServer.lua

AttackRemote.OnServerEvent:Connect(function(player)
    registerHit()
    damage(25)
end)

BlockRemote.OnServerEvent:Connect(function(player, state)
    setBlockState(state)
end)

This is intentionally simplified.

A real combat system would likely validate things such as:

• distance
• cooldowns
• hitboxes
• targets
• character state

Combat UI

The UI reacts to combat state automatically.

CombatUI.lua

local effect = Reheaven.effect

effect(function()
    local state = combatState()

    healthLabel.Text = `{state.health}/{state.maxHealth}`
    comboLabel.Text = `Combo: {state.combo}`
end)

effect(function()
    local state = combatState()

    blockIcon.Visible = state.blocking
    stunnedIcon.Visible = state.stunned
end)

You never need to manually refresh the UI.

Updating the state is enough.

Client Input

The client can request combat actions.

CombatInput.lua

UserInputService.InputBegan:Connect(function(input, gameProcessed)
    if gameProcessed then
        return
    end

    if input.KeyCode == Enum.KeyCode.F then
        BlockRemote:FireServer(true)
    end
end)

UserInputService.InputEnded:Connect(function(input)
    if input.KeyCode == Enum.KeyCode.F then
        BlockRemote:FireServer(false)
    end
end)

Combat Flow

Client Input
↓
Remote Event
↓
Server Validation
↓
Combat Action
↓
Combat State Changes
↓
UI Reacts

Server Authority

Do not trust the client for combat decisions.

The client can request actions, but the server should decide what actually happens.