I am new to this group and this is my first post. I am in a way of
learning and knowing more about panoramas and its process since last
whole year. I have gone through almost all tutorials (including
panotools and hugin's) and many other papers on google and those on
other universities's site. But till date, I am not able to find the
exact foumullas to stitch images in to an equirectangular pano. 6
months ago, I was limited to only cylindrical and partial spherical
projections. But as I came across the full view 360x180
equirectangular one, it seemed interesting to me(a lot, in fact). But
let me very frank, since those last 6 months, I have been stuck on
that only. I tried searching everywhere, but I didn't find "HOW TO
ACTUALLY MAKE IT". Then I looked at panotools. The source has some
methods of generation of an equi panorama. I tried understanding it
many times, but still i am not getting it.

Can anyone here, show or point me exactly to that part in code which
applies distortion on equirectangular pano. This has nothing to do
with the stitching part. Just projection is involved.

The tutorials online and most other documents don't actually go deep
in to it. Can anybody help?