Lighting

07 - Lighting

Every sector has a light property: a Vector3 of red, green, blue in the range 0-255 (255, 255, 255 is full white, 0, 0, 0 is dark). sector.light.x = 0 changes one channel; a value stored in a variable is a copy, so assign it back after changing it.

local base = sector.light                     -- copy
sector.light = Vector3(base.x * 0.5, base.y * 0.5, base.z * 0.5)   -- half brightness

All scripts on this page are sector scripts.

---

Flicker

Attach to: a sector with a broken light.

Holds a random brightness for a random short time, then picks another.

-- Scripts/Lighting/Flicker.lua (sector script)
public number minBrightness = 0.3
public number maxBrightness = 1.0
public number minInterval = 0.03
public number maxInterval = 0.15

local base
local timer = 0.0

function Start()
    base = sector.light   -- remember the light the designer painted
end

function Update()
    timer = timer - GameTime.deltaTime
    if timer > 0 then return end

    timer = mathT.RandomF(minInterval, maxInterval)
    local k = mathT.RandomF(minBrightness, maxBrightness)
    sector.light = Vector3(base.x * k, base.y * k, base.z * k)
end

function OnDisable()
    if base ~= nil then sector.light = base end   -- restore
end

---

Smooth pulse

Attach to: a sector with a glowing thing: a reactor room, a heartbeat.

-- Scripts/Lighting/Pulse.lua (sector script)
public number period = 2.0
public number minBrightness = 0.35
public number maxBrightness = 1.0

local base
local clock = 0.0

function Start()
    base = sector.light
end

function Update()
    clock = clock + GameTime.deltaTime

    -- Sine wave remapped from -1..1 to 0..1, then to minBrightness..maxBrightness.
    local wave = 0.5 + 0.5 * math.sin(clock / period * 2 * math.pi)
    local k = mathT.Lerp(minBrightness, maxBrightness, wave)

    sector.light = Vector3(base.x * k, base.y * k, base.z * k)
end

---

Alarm strobe

Attach to: a sector that should flash red while an alarm is on.

The alarm is a channel in the shared Global table (the same trick the doors use), so any script can trigger it: Global.channels = Global.channels or {} then Global.channels["alarm"] = true.

-- Scripts/Lighting/AlarmStrobe.lua (sector script)
public string channel = "alarm"
public number flashesPerSecond = 2
public Vector3 alarmColor = Vector3(255, 0, 0)

local base
local clock = 0.0
local wasActive = false

function Start()
    base = sector.light
end

function Update()
    local active = Global.channels ~= nil and Global.channels[channel] == true

    if not active then
        if wasActive then
            sector.light = base   -- alarm just ended: restore the normal light
            wasActive = false
        end
        return
    end

    if not wasActive then
        wasActive = true
        clock = 0.0   -- restart the flash pattern each time the alarm begins
    end

    clock = clock + GameTime.deltaTime

    -- Two half-cycles per flash: even = alarm color, odd = dark.
    local lit = math.floor(clock * flashesPerSecond * 2) % 2 == 0

    if lit then
        sector.light = alarmColor
    else
        sector.light = Vector3(base.x * 0.15, base.y * 0.15, base.z * 0.15)
    end
end

Notes

• Every strobe sector restarts its clock on the frame the alarm switches on, so sectors that share a channel flash in sync without needing a shared timer.
• A Vector3 public field (alarmColor) can be assigned straight to sector.light.

---

Day / night cycle

Attach to: an outdoor sector (or one script per outdoor sector).

Blends through a list of colors over a day.

-- Scripts/Lighting/DayNight.lua (sector script)
public number dayLength = 120
public number startTime = 0.5

-- One entry per key moment of the day, evenly spaced from midnight (0) around to midnight (1).
local KEYFRAMES = {
    {40, 50, 90},      -- midnight
    {255, 170, 110},   -- dawn
    {255, 255, 255},   -- noon
    {255, 130, 80},    -- dusk
    {40, 50, 90},      -- midnight again (so it loops)
}

local clock = 0.0

local function SampleDay(t)
    local segments = #KEYFRAMES - 1
    local scaled = (t % 1) * segments
    local index = math.floor(scaled)
    local blend = scaled - index

    local a = KEYFRAMES[index + 1]
    local b = KEYFRAMES[index + 2]

    return Vector3(
        mathT.Lerp(a[1], b[1], blend),
        mathT.Lerp(a[2], b[2], blend),
        mathT.Lerp(a[3], b[3], blend)
    )
end

function Start()
    clock = startTime
end

function Update()
    clock = (clock + GameTime.deltaTime / dayLength) % 1
    sector.light = SampleDay(clock)
end

Notes

• % is Lua's modulo, so (t % 1) keeps the time inside 0..1.
• The keyframe table is plain Lua data. Add more entries to add more moods, and the math adapts because it uses #KEYFRAMES.

---

Light switch

Attach to: the sector whose lights you want to toggle.

Press a key while standing in the sector to toggle its lights.

-- Scripts/Lighting/LightSwitch.lua (sector script)
public Entity player = nil
public Key toggleKey = Key.F
public number offBrightness = 0.1

local base
local lightsOn = true

local function PlayerIsInside()
    for i = 1, sector.entityCount do
        if sector:GetEntity(i).id == player.id then return true end
    end
    return false
end

function Start()
    base = sector.light
end

function Update()
    if player == nil or not Input.GetKeyDown(toggleKey) or not PlayerIsInside() then return end

    lightsOn = not lightsOn

    if lightsOn then
        sector.light = base
    else
        local k = offBrightness
        sector.light = Vector3(base.x * k, base.y * k, base.z * k)
    end
end