SCNTransparencyMode.rgbZero
SceneKit derives transparency information from the luminance of colors. The value 0.0 is opaque.
Declaration
case rgbZeroDiscussion
When using this mode, SceneKit ignores the alpha value of colors in the material’s transparent property. SceneKit calculates the luminance of a color from its red, green, and blue channels and uses the resulting value to determine the material’s opacity.