OpenGL stencil analysis #1

OpenGL OpenGL: Basic Coding
1

I have decided to go thru stenciling process ONE step at the time.
I hope it is OK with the forum.
I got the initialization , enabling and clearing , working OK.
Next is setting for the stencil.
glStencilFunc supposedly passes the baton to next call ( glStencilOp ) , depending on setting of reference and mask - all SINGLE bits.
However, if the function is set to GL_ALWAYS are both reference and mask ignored ?
And what hap[pens with code flow if the glStencilFunc fails?
Can I use glGet to verify that glStencilFunc passed / failed ?

		// setup stencil function
		// function  - test always 
		// reference - anything ?? 
		// mask         - anything ?? 
		glStencilFunc(GL_ALWAYS, 1, 1);

I am truly sorry to be such pain, but I need this stenciling process to be well defined, each step, bullet-proof, not just "try this and watch for smoke ".

For example - right now my stencil test passes part (correct) of text bitmap, but also passes everything else NO change.

2

Yes. Also for GL_NEVER.

The fragment is discarded. Neither the colour buffer(s) nor depth buffer are updated for that fragment. If the fragment shader has any observable side effects beyond writing to the framebuffer (e.g. writes to images, atomic counters or buffer variables), it will still be executed unless the early_fragment_tests layout qualifier is used.

The stencil buffer will be updated according to the first parameter to glStencilOp.

No.