No, there is no simple way to do 3D plots in spherical coordinates to display within any device which is inherently regularly-spaced cartesian coordinates. This is a mathematical issue, not a MATLAB problem.
To get the best approximation, you should first calculate the cartesian coordinates of each pixel to be rendered to, and back-project those to spherical coordinates, and do the function calculations at each of those spherical coordinates. This is the "pull" technique of rendering, whereas what you are using is the "push" technique (calculating destination coordinates from source coordinates), which is known to necessarily fail in some cases.
A problem, though, is that when you calculate the cartesian coordinates, you should take in to account the view projection from 3D to 2D that the rendering will necessarily undergo. Calculating proper source Z coordinates back from a flat image can be a bit tricky. And if you rotate the view, you need to recalculate destination and source locations and then recalculate the function values.
If this sounds like I am saying that you can either have accurate rendering or ease (and number of times) of function calculation, but not both, then Yes, that would be correct. "push" from spherical to cartesian will always give poor rendering, "pull" will require repeated recalculations as your view changes.
