The camera component defines from which perspective the user views the scene. The camera is commonly paired with controls components that allow input devices to move and rotate the camera.
A camera should usually be positioned at the average height of human eye level (1.6 meters). When used with controls that receive rotation or position (e.g. from a VR device) this position will be overridden.
<a-entity camera look-controls position="0 1.6 0"></a-entity>
When moving or rotating the camera relative to the scene, use a camera rig. By doing so, the camera’s height offset can be updated by roomscale devices, while still allowing the tracked area to be moved independently around the scene.
<a-entity id="rig" position="25 10 0">
|active||Whether the camera is the active camera in a scene with more than one camera.||true|
|far||Camera frustum far clipping plane.||10000|
|fov||Field of view (in degrees).||80|
|near||Camera frustum near clipping plane.||0.005|
|spectator||Whether the camera is used to render a third-person view of the scene on the 2D display while in VR mode.||false|
|zoom||Zoom factor of the camera.||1|
If a camera is not specified, A-Frame will inject a default camera:
<a-entity camera="active: true" look-controls wasd-controls position="0 1.6 0" data-aframe-default-camera></a-entity>
If a camera is specified (e.g., our own
then the default camera will not be added.
When exiting VR, the camera will restore its rotation to its rotation before it entered VR. This is so when we exit VR, the rotation of the camera is back to normal for a desktop screen.
Far, near, fov, zoom properties only apply in 2D and magic window modes. In VR mode the camera parameters are supplied by the WebVR / WebXR API to match IPD and headset FOV. Those aren’t configurable.
Changing the Active Camera
active property gets toggled, the component will notify the camera system
to change the current camera used by the renderer:
var secondCameraEl = document.querySelector('#second-camera');
Fixing Entities to the Camera
To fix entities onto the camera such that they stay within view no matter where the user looks, you can attach those entities as a child of the camera. Use cases might be a heads-up display (HUD).
<a-entity camera look-controls>
Note that you should use HUDs sparingly as they cause irritation and eye strain in VR. Consider integrating menus into the fabric of the world itself. If you do create a HUD, make sure that the HUD is more in the center of the field of view such that the user does not have to strain their eyes to read it.
Reading Position or Rotation of the Camera
To actively read the position or rotation of the camera, use a
of a component that reads the position or rotation, and does something with it.
Then attach the component to the camera.
Reading World Position or Rotation of the Camera
three.js has methods to attain position or rotation (or scale) in world space versus object local space.