Why does rlVertex2f() not use z=0?

[paulmelis]

It seems that for GRAPHICS_API_OPENGL_33 the function rlglvertex2f() actually calls

rlVertex3f(x, y, RLGL.currentBatch->currentDepth);

Yet for GRAPHICS_API_OPENGL_11 it calls

glVertex2f(x, y);    // z is implicitly 0

Why is z not consistently 0? And any way to control the currentDepth value?

Edit: some background is that I'd like to use some of the 2D functions, such as DrawSplineBasis() in 3D, by transforming the XY coordinates they produce to whatever I need. Yet, they call rlVertex2f(), so the Z value seems to be out of my control

[Hex4dec]

Well, this is C, no? Just set the RLGL.currentBatch->currentDepth variable yourself! We don't have any private variables!

[paulmelis]

It's there for a reason, and I'd like to understand why.

Also, RLGL is not available from rlgl.h unless you define RLGL_IMPLEMENTATION before including it. But rcore.c already does that, so the variable is effectively hidden (as it's also marked static)