maximumExposure
The minimum exposure value to use in tone mapping.
Declaration
var maximumExposure: CGFloat { get set }Discussion
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 minimumExposure, maximumExposure, exposureOffset, and whitePoint properties, along with a measure of scene luminance.
Exposure values are exponential: a value of 1.0 doubles brightness, a value of 2.0 quadruples brightness, a value of -1.0 halves brightness, and so on. The default value is 15.0. Decreasing the value causes brighter portions of the scene to become over-exposed (uniformly white, losing definition). Increasing the value adds more dynamic range for brighter portions of the scene; however, a greater breadth of difference between the minimum and maximum exposures decreases contrast.