Dual [page:PerspectiveCamera PerspectiveCamera]s used for effects such as [link:https://en.wikipedia.org/wiki/Anaglyph_3D 3D Anaglyph] or [link:https://en.wikipedia.org/wiki/parallax_barrier Parallax Barrier].
[example:webgl_effects_anaglyph effects / anaglyph ]
[example:webgl_effects_parallaxbarrier effects / parallaxbarrier ]
[example:webgl_effects_stereo effects / stereo ]
Default is `1`.
Default is `0.064`.
Left camera. This is added to [page:Layers layer 1] - objects to be rendered by the left camera must also be added to this layer.
Right camera.This is added to [page:Layers layer 2] - objects to be rendered by the right camera must also be added to this layer.
Update the stereo cameras based on the camera passed in.
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]