Out-of-gamut colors produced by inverse tone mapping cause hue shifts

Hello!
As stated in this issue in the maintained Sceneform repository (https://github.com/ThomasGorisse/sceneform-android-sdk/issues/60) the `inverseTonemapSRGB` function makes the colors with the full pixel intensity appear incorrectly. Is it because the `inverseTonemapSRGB` function is an approximation and isn't suitable for converting colors from the sRGB space to the linear space (I think that is why it is used in the `ViewRenderable` material in Sceneform)?