filament-compose/io.github.erkko68.filament.compose.scene/CameraState

CameraState

Hoisted, observable camera state. Create with rememberCameraState and pass to io.github.erkko68.filament.compose.FilamentView for full control over the camera.

All fields are observable androidx.compose.runtime.MutableState — read them inside a composable to subscribe to changes, or write them from anywhere on the main thread to drive the camera imperatively.

Read-only matrices (viewMatrix, projectionMatrix) reflect the underlying Filament camera and are valid only while the state is attached to a FilamentView.

val cameraState = rememberCameraState(initialEye = Position(0f, 2f, 5f))
FilamentView(scene = scene, cameraState = cameraState)

// Read the view matrix from anywhere
LaunchedEffect(cameraState.eye) {
    val v = cameraState.viewMatrix  // may be null until attached
}

Properties

exposure

var exposure: Exposure

eye

var eye: Position

focusDistance

var focusDistance: Float

Distance from the camera to the plane of focus in world units, used by PostProcessing(depthOfField = …) to place the focal plane. Ignored without DoF.

projection

var projection: Projection

projectionMatrix

val projectionMatrix: Mat4?

Projection matrix (view→clip) computed by Filament. Null until this state is attached to a io.github.erkko68.filament.compose.FilamentView.

scaling

var scaling: LensScaling

Per-axis projection scaling; LensScaling.Identity leaves the frustum as computed.

shift

var shift: LensShift

Off-axis lens shift; LensShift.None leaves the projection centred.

target

var target: Position

var up: Direction

viewMatrix

val viewMatrix: Mat4?

View matrix (world→view) computed by Filament. Null until this state is attached to a io.github.erkko68.filament.compose.FilamentView.