About theta and phi in directivity definition

[kirinf]

Dear author,

https://github.com/GAMMA-UMD/pygsound/blob/8f41cb13da5dba9aa09cac3f42e668005ed5cf11/src/GSound/gsound/gsSoundDirectivity.cpp#L152C1-L179C160

In gsSoundDirectivity.cpp, According to the Macro definition of SPHERICAL( theta, phi ), it's

[0, 0, 1; 0, 1, 0; 1, 0, 0] * [ sin(theta) * cos(phi), sin(theta)*sin(phi), cos(theta) ]' =
[ cos(theta), sin(theta)*sin(phi), sin(theta) * cos(phi) ]',

which means x = cos(theta), y = sin(theta)*sin(phi), z = sin(theta) * cos(phi).

So I think theta represents angle between ray and X-axis; phi represents angle between ray's projection in YZ plane and Z-axis (as shown in the figure below).

Is my understanding correct?