Raytracing integrated range

[chrisflesher]

I am wondering if it would make sense to add something to mb_rt to provide the flight distance the beam traveled? For example this could be useful for re-calculating attenuation loss through the water column (often the sonar firmware calculates this but it is not very accurate).

Would it be easy to add a rplot similar to the xplot, zplot, and tplot variables that returns range traveled by the ray? Also maybe an r output for total range traveled at the end of computation? Or maybe dplot / d are better variable names?

Right now I am calculating the distance the beam traveled using xplot and zplot points, drawing line segments between those but this is not going to be super accurate because the lines are not actually straight. It seems like some kind of integration with raytracing might provide the most accurate result?