Jump to content
  • Advertisement


This topic is now archived and is closed to further replies.


x,y coordinates to a direction

This topic is 5855 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I need to find the direction (N, NE, E, SE, S, SW , W, NW) to a x, y destination coordinate from an x, y source coordinate. Im sure this is probably quite a simple formula unfortunately maths is not my strongest point. I need to create a function: int directionToCoord(POINT source, POINT destination) that will return an integer for the direction: 0 = North 1 = North East 2 = East 3 = South East etc. Does anybody have any ideas how I can achieve this, I was quessing that I probably have to firstly find the angle between the two points (from due North) and then split the 360 degrees up into the directions, but I have no idea how I can actually perform this. Any help would be greatly appreciated..

Share this post

Link to post
Share on other sites
no idea?

u know how to calculate sin right? (x^2+y^2)^0.5/y


if (x<0) angle=PI-angle;

I think that will work.


Share this post

Link to post
Share on other sites
dx = destx - startx
dy = desty - starty
angle = atan2(dy, dx);

Now that you have the angle, find the direction it is closest to (ie.: split the 360 degrees into 8 X 45 degrees), but beware that atan2 returns radians.


Share this post

Link to post
Share on other sites
I followed Cedric''s example because I couldn''t see how fluffysteve''s would work because it didnt seem to take the source AND dest x,y points into account.

What I came up with was:

double angle = atan2(dest.y-source.y, dest.x-source.x) * 180 / PI;

And it works perfectly, it returns the correct angle!!

Thanks for your help.

Share this post

Link to post
Share on other sites

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!