Thomas et al;

It occurred to me, that during our last discussion of 3D mapping etc, that 
you'd asked how I was converting my arc tangent result to a bearing with zero 
being north and degrees ascending clockwise. Here's how I do it. this is my own 
way, and is only for a flat plane which is perfect for games. There are other 
formulae out there, but they take into account earth curvature. This is not as 
elegant as I'd like, but is less expensive than other formulae. -Perhaps 
someone else knows of a better formula?… -Would love to hear!… :)

Anyway, this way is very simple. Hope it helps! :)


Cara :)

// x1, y1 is the user's origin and x2, y2 is the point you're trying to get the 
angle to.

// subtract the remote point from your origin
// it's important to do this in this order or the result will be opposite what 
you want
// I.E. 270 degrees instead of 90 etc

double vectorX = x2 - x1;
double vectorY = y2 - y1;

        // get the angle in degrees between the two points
        double angle = (atan2(vectorY, vectorX) * 180 / 3.1415926535);
        // get the value in the proper negative range
angle-= 450;
        // switch to positive so that degrees will ascend clockwise as with a 
proper heading
        angle = angle * -1;
        // round off result so modulus will be accurate
        angle = round(angle);
        // use modulus of 360 to get result in the proper range
        angle = (int)angle % 360;

// return the result;

return angle;
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