[x3d-public] Which color space for Background color interpolation

[Andreas Plesch]

The Background specification in

https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/enveffects.html#Backgrounds

states that

"The sky colour is linearly interpolated between the specified
skyColor values." and
"The ground colour is linearly interpolated between the specified
groundColor values."

The ColorInterpolator specification in

https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/interp.html#ColorInterpolator

states that

"A linear interpolation using the value of set_fraction as input is
performed in HSV space."

The ColorInterpolator language is more precise in giving the space in
which linear interpolation should be performed.

I think there is a need to also become more precise for Background
color interpolation. The consistent approach would be to choose HSV
space there as well:

"The sky colour is linearly interpolated in HSV space between the
specified skyColor values." and
"The ground colour is linearly interpolated in HSV space between the
specified groundColor values."

HSV space probably also leads to more aesthetically pleasing backgrounds.

[x3dom currently performs all color interpolation in RGB space].

Do we need such a clarification ?

-Andreas
-- 
Andreas Plesch
Waltham, MA 02453