Shadow Performance

Thanks for sharing Falcor.
There are plenty game engines out there, but very few render engines.
This could fill a void.

I managed to build Falcor on Ubuntu 16.04.4.
(Took manual build from source for ffmpeg and libglfw3, as those are too old on Ubuntu LTS.)

When I run the Shadow Sample, it struggles to even reach 14 FPS on my GTX 750 Ti.

What could be the reason for the poor performance?
I understand that it is an older GPU, yet Shadow mapping should not be that much of a challenge, surely?

Note that SimpleDeferred renders at 620fps, although that demo opens a smaller window.

NormalMap renders at 234fps for me at start up, but slows down to a trickle if I zoom in on the face.
It reports 40fps at that case, but is running much slower than reported.

I made some optimizations to the CSM class in the dev-3.0 branch.
One of the optimizations was to have a proper async SDSM buffer readback. I didn’t check performance on Linux yet - we were focusing on Windows and will spend the first week of April to make sure Linux works correctly. I also check the perf then.

Thanks for reporting all the issues!