Fog drawing information for use in GLKit rendering effects.
- iOS 5.0+
- macOS 10.8+
- tvOS 9.0+
These properties are specifically designed to mimic the fog calculations provided by OpenGL ES 1.1.
When fog is enabled, the fog component is calculated and clamped to a range from
1. Then, the fog value is used as a blending factor between the computed fragment color and the fog color.