How do the symbols r, o, and i related to the polar coordinates (Rho, Phi, and Theta) [closed]

Solution 1:

You can look at the cartesian transformation that he uses to tell what the angles are.

// convert back to cartesian coordinates
    w.x = wr * sin(wo)*sin(wi);
    w.y = wr * cos(wo);
    w.z = wr * sin(wo)*cos(wi);

On the other hand, the typical representation (matching your picture) is

$$x = r\sin(\theta)\cos(\varphi) \\ y = r\sin(\theta)\sin(\varphi) \\ z = r\cos(\theta)$$

So he is using o for $\theta$ and i for $\varphi$, but his cartesian coordinates are flipped in the sense that w.x is really $y$, w.y is really $z$, and w.z is really $x$.