Faulty Angle Function

[BlueMirage]

I'm using a simple function to determine the angle between two points. You should be able to recognize it.

function Angle takes real x1, real y1, real x2, real y2 returns real
    local real r = bj_RADTODEG * Atan2(y2 - y1, x2 - x1)
    call BJDebugMsg(R2S(r))
    return r
endfunction

However, for some odd reason this gives me faulty values when r > 180 degrees. If I for example should get 190 degrees, I get -170. 200 degrees gives me -160. 350 degrees gives me -10.

Anybody have an idea why?

 

[Romek]

-170 and 190, 350 and -10, etc are equal in terms of degrees; so your values are not 'faulty'.
If you insist on a value between 0 and 360 though, you could use:

function Angle takes real x1, real y1, real x2, real y2 returns real
    local real r = ModuloReal(bj_RADTODEG * Atan2(y2 - y1, x2 - x1), 360.)
    call BJDebugMsg(R2S(r))
    return r
endfunction

 

[Trollvottel]

As Romek said, Atan2 returns values from -180 to 180 degrees ( or -pi to pi)...

if you want to have angles from 0 to 360 degrees you have to use

if r < 0 then
set r = 360 + r
endif

 

[BlueMirage]

Well, this explains why my spells have been malfunctioning half of the time.
I appreciate it. +rep