Sample to access extrinsics

[kianwei96]

Hi! Love this work, it's been really helpful thus far. Excited to test out the VLC streaming soon too!

Just wondering, would it be easy to stream the corresponding extrinsics per frame, (for depth and spatial cameras)? I think that would be very useful for people to generate visualizations or perform computation with a moving device across time :)

I see that there's a "LfToWorld" in the HL2ResearchMode.cpp file, but I don't think it's accessible right now?

Thanks, and looking forward to future updates :)