Instance Property

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.

This property has no effect if the wantsHDR value is false.

See Also

Adding High Dynamic Range Effects

var wantsHDR: Bool

A Boolean value that determines whether SceneKit applies High Dynamic Range (HDR) postprocessing effects to a scene.

var exposureOffset: CGFloat

A logarithmic bias that adjusts the results of SceneKit’s tone mapping operation, brightening or darkening the visible scene.

var averageGray: CGFloat

The luminance level to use as the midpoint of a tone mapping curve.

var whitePoint: CGFloat

The luminance level to use as the upper end of a tone mapping curve.

var minimumExposure: CGFloat

The minimum exposure value to use in tone mapping.