SDL2 pinch zoom

Hi!

Many months ago I was using SDL 1.3 before the SetLogicalSize and SetScale
were implemented, and was trying to figure out a way to portably implement
zoom. My experience with 3D rendering is very limited, and I put the
exercise off.

Now, looking at the scale and viewport functions, it looks possible to
implement a pinch zoom in pure SDL2. I am having a bit of trouble with
setting the viewport properly, I’m sure I can work through the bugs, but
I’m more interested in seeing if anyone has done this already or if I’m
even approaching this the right way at all.

Regards,
Jeremy J.

PS. My iOS game has been using SDL since 1.3 in 2011 and I have had NO
major problems with it. Thanks to all you nice people!