Camera functions

Control camera position, visual effects, and zoom from Lua scripts.

Rustic Engine has two cameras:

• camGame — The game world camera. Follows the current singer and can be zoomed or shaken.
• camHUD — The HUD overlay camera. Fixed to the screen. The health bar, score, and combo display are drawn here.

Rustic Engine’s camera zoom interpolation is smoother than Psych Engine’s original bump implementation. The Lua API is identical — your scripts work without changes.

Zoom control

Camera zoom is controlled through the tween system and the property system. There are no standalone setCamZoom functions — use doTweenZoom for animated zoom or setProperty for an immediate change:

-- Animated zoom (recommended)
doTweenZoom("bossZoom", "camGame", 1.3, 0.8, "cubeOut")

-- Immediate zoom via property write
setProperty("defaultCamZoom", 1.1)

The defaultCamZoom property controls the resting zoom level that the engine returns to between beat bumps. Set it during onCreate or from a chart event:

function onEvent(name, value1, value2)
  if name == "Change Zoom" then
    setProperty("defaultCamZoom", tonumber(value1) or 0.9)
  end
end

See Tween functions for the full doTweenZoom signature.

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Camera effects

cameraShake

Applies a screen shake effect to a camera.

camera · string · required

Camera to shake: "camGame" or "camHUD". Aliases "game" and "hud" are accepted.

intensity · number · required

Shake magnitude. Typical values are 0.005 (subtle) to 0.05 (strong).

duration · number · required

How long the shake lasts, in seconds.

-- Subtle shake on miss
function noteMiss(membersIndex, noteData, noteType, isSustainNote)
  cameraShake("camGame", 0.01, 0.2)
end

-- Heavy shake for an impact event
function onEvent(name, value1, value2)
  if name == "Impact" then
    cameraShake("camGame", 0.04, 0.5)
    cameraShake("camHUD", 0.02, 0.3)
  end
end

cameraFlash

Flashes a solid color over a camera briefly.

camera · string · required

Camera to flash: "camGame" or "camHUD". Aliases "game" and "hud" are accepted.

color · string

Hex color string (e.g. "FFFFFF" for white, "FF0000" for red). Defaults to "FFFFFF".

duration · number · default: "0.5"

Duration of the flash in seconds.

forced · boolean

Reserved for Psych Engine compatibility. Has no effect currently.

cameraFlash("camGame", "FFFFFF", 0.3)

customFlash

Like cameraFlash but accepts an options table with an alpha key for controlling flash opacity.

camera · string · required

Camera to flash.

color · string

Hex color string. Defaults to "FFFFFF".

duration · number · default: "0.5"

Duration in seconds.

options · table

Optional table. Supports alpha key (default 0.75).

customFlash("camGame", "FF0000", 0.5, {alpha = 0.5})

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Camera position

cameraSetTarget

Requests the camera to follow a named character target.

target · string · required

Character to follow: "dad", "boyfriend", or "gf".

function onEvent(name, value1, value2)
  if name == "Focus Camera" then
    cameraSetTarget(value1) -- e.g. "dad" or "boyfriend"
  end
end

moveCameraSection

Moves the camera to the position dictated by a chart section’s mustHitSection flag, as if that section had just started.

section · number · default: "0"

Section index in the chart (0-based).

moveCameraSection(0) -- reset to section 0's camera position

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Integrating tweens with camera

Camera zoom works naturally with the tween system:

function onSongStart()
  -- Zoom in on song start, then return to default
  doTweenZoom("introZoom", "camGame", 1.4, 1.5, "cubeOut")
  runTimer("introEnd", 1.5, 1)
end

function onTimerCompleted(tag, loops_done, loops_left)
  if tag == "introEnd" then
    doTweenZoom("introZoomBack", "camGame", defaultCamZoom, 0.8, "quadInOut")
  end
end

function onBeatHit()
  -- Pulse zoom on every other beat
  if curBeat % 2 == 0 and cameraZoomOnBeat then
    doTweenZoom("beatBump", "camGame", defaultCamZoom + 0.03, 0.1, "quadOut")
    runTimer("bumpRestore", 0.1, 1)
  end
end

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Relevant globals

These globals are synced into your script before each callback and are safe to read:

Global	Type	Description
defaultCamZoom	number	Current default camera zoom (writable via setProperty)
cameraSpeed	number	Camera follow speed multiplier
cameraZoomOnBeat	boolean	Whether the engine auto-bumps zoom on beats