Spherical Coordinates Color Space
PLESAE NOTE! The DCTL's are still experimental. You might experience some glitches. If you see some color's artifacting black, they usually disappear when you slightly modify an RGB curve in-between the two conversion DCTL's. At this stage I am not sure if it is the math or a glitch in Resolve.
In the image above you can see how I set up the color space transforms in Fusion. The color curves node is where you can manipulate the RGB channels simply. For more complex use cases you can setup keys etc. or develop your own DCTL that can do more nuanced operations.
As mentioned above, there are still some glitches. The upcoming weeks I do not have time to work on it due grading gigs. So, if you manage to fix some of the bugs by modifying the code, please send it to me so I can update it, and credit you as a contributor.
*V2 is with modified code to make the conversion fit inside the RGB cube. This way the curves responds as expected.