When the Android phone is on its side (horizontal orientation), the Roll represents the tilt, so to speak. When the phone is perpendicular to the ground (looking directly at the screen), the roll says 90. However, when you start tilting it forward or backward, as if you wanted to look down or up, the angle just decreases either way.
This means looking up or down 45 degrees gives the same roll or 45 degrees.
How is it possible to know if you are rolling it forward or backward?
I have been looking around for an answer to this, and can't find anyone else with this problem. Judging from different apps, it seems to be possible, so I think I am just missing some relationship to something, and was hoping someone might be able to nudge me in the right direction. Thanks!