Some questions on windows, viewports and buffers....

I’d like to know…is the 2D position specified in glReadPixels() or glViewport() defined wrt the origin at lower-left corner of the window’s client area?
As for the case of exclusive full-screen mode, is the origin at the lower-left corner of the screen?
For that matter, I presume the frame buffer has the same dimensions as the window’s client area?
Does the front/back frame buffer each have its own color, depth and stencil buffers?
What about the aux buffers? Do they also each have their own color, depth and stencil buffers?
The accum color buffer…is there only 1 of this?

Oh, and 1 more question…are so-called “window coordinates” of the processed vertices(after viewport transformation in the OpenGL pipeline) defined wrt the lower-left corner of the viewport? (and not, as the name would imply, wrt the lower-left corner of the window…)

2D coordinates are always defined from the lower-left corner of your viewport.

the back buffer and front buffer store there diferent color values. there is one depthbuffer and one stencil buffer.

bout aux and accum buffer i don’t know, they are not supported on consumer hardware anyway