Compute central angle between two rotation matrices, for a direction vector

Source: R/maths_functions.R

For a given direction vector, computes the central angle between the rotated versions of the vector.

rot2centralangle(R1, R2, e)

Arguments

R1

First rotation matrix

R2

Second rotation matrix

e

Base vector (e.g. c(0,0,1) for forward gaze), magnitude is ignored

Value

Angle in degrees

Details

This is different from the distance between the rotations, because rotations around the direction vector are ignored here. This is useful for computing visual scan speed where rotation around the eye axis is irrelevant.