Start of line (yellow) and axes at [xc,yc,zc]
End of line is at [xp,yp,zc].
a,b,c are the angles which line makes in space.
What I need are the angles which line's projections (black line) create on xy,yz and xz planes.
- A_y_to_z: Projected line's angle from y axis to z axis on xz plane.
- A_z_to_x: angle from z to x axis on zx plane.
- A_x_to_y: Angle from x to y axis on xy plane.