Re: [NTG-context] atan2 function

14 Oct 2022

      That's certainly tighter, thank you, Alan.

Would making the conditional part of the API be useful to others?

Cheers!

On Fri, Oct 14, 2022 at 3:42 PM Alan Braslau  wrote:
...
On Fri, 14 Oct 2022 11:59:49 -0700
Thangalin  wrote:
...
I don't think an atantwo is needed. I *thought* I had read somewhere
that atan( y, x ) was equivalent to calling atan2 in Lua. Ensuring
there's no breakage when x == y would be nice, though. It was a little
surprising to see angle return degrees rather than radians, but it
does simplify my code:
dc := vbc - vac;
      dr := vbr - var;
      vi := 0;
if not( dc == dr ):
        vi := round( angle( dc, dr ) / 60 );
      fi;
% Compute the direction towards the first segment (to vertex of
an edge). vangle := vi * 60 * pi / 180;
Even simpler would be:
dc := vbc - vac;
      dr := vbr - var;
      vi := round( angle( dc, dr ) / 60 ); % returns 0 when dc == dr
% Compute the direction towards the first segment (to vertex of
an edge). vangle := vi * 60 * pi / 180;
Or accepting a third argument as the return value in the special case:
vi := round( angle( dc, dr, 0 ) / 60 ); % returns 0 when dc ==
dr
Cheers!
vi := if (dc = dr) : 0 else : round (angle(dc,dr)/60) fi ;
Alan