Where can I set TestFunc?

There is RenderState.TestFunc. But I can’t find any reference for this.

How could I use TestFunc? Is it not implemented yet or not needed anymore?

It is not used at the moment.

I added it because I had a use for it, but then I re-thinked it.

Then what should I do to set zbuffer TestFunc property?

Its set automatically to “Less”. You don’t need to change it.

I’m afraid I’m not catching you because I’m not familiar with OpenGL 3.

I guess I could do the same thing in TestFunc.Always, LessThanOrEqualTo, etc using ViewPort, Polygon Offset.

But is it more efficient to use TestFunc?

Or should I use shader in OpenGL3?

No, this has nothing to do with OpenGL3. The function is automatically set to “Less”, because thats usually what you want when you do depth testing.