The luminance level to use as the midpoint of a tone mapping curve.
- iOS 10.0+
- macOS 10.12+
- tvOS 10.0+
- watchOS 3.0+
When using a High Dynamic Range (HDR) camera, SceneKit applies a process called tone mapping to translate the wide range of luminance values in the visible scene to the narrower range of brightness values that can be shown on a display. SceneKit determines a tone mapping curve from the
white properties, along with this property which serves as a constant estimate of scene luminance.
The default value is
0. By setting this property to a higher or lower value, you can compensate for scenes with darker or brighter content. Alternatively, by setting the
wants property, you can allow SceneKit to automatically adjust exposure as the visible contents of the scene change.
This property has no effect if the
wants value is
false. If the
exposure value is
true, SceneKit ignores this property, and instead computes the average luminance currently visible to the camera during rendering.