Java-Gaming.org    
Featured games (79)
games approved by the League of Dukes
Games in Showcase (477)
Games in Android Showcase (107)
games submitted by our members
Games in WIP (536)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
 
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  Simpler way to calculate angle between two points?  (Read 2959 times)
0 Members and 1 Guest are viewing this topic.
Offline appel

JGO Wizard


Medals: 50
Projects: 4


I always win!


« Posted 2006-01-02 07:20:01 »

I'd like to know if there is a simpler way to calculate the angle between two points.

I'm currently using this method:

1  
2  
3  
4  
5  
6  
7  
8  
9  
10  
11  
12  
13  
14  
15  
16  
17  
18  
public static float angle(float x1, float y1, float x2, float y2)
    {
        float dx=x2-x1,dy=y2-y1, PI=(float)Math.PI;
        double angle=0.0f;
       
        if(dx==0)
           if(dy==0)angle=0;
           else if(dy>0)angle=PI/2;
           else angle=PI*3/2;
        else if(dy==0)
           if(dx>0)angle=0;
           else angle=PI;
        else if(dx<0)angle=Math.atan(dy/dx)+PI;
        else if(dy<0)angle=Math.atan(dy/dx)+(2*PI);
        else angle=Math.atan(dy/dx);

        return (float)angle;
    }


Seems like a awful alot for something simple as that.

I'd like the angle to be 0 at 3 o'clock, and moving clockwise it should be PI at 9 o'clock. Any ideas?

Check out the 4K competition @ www.java4k.com
Check out GAMADU (my own site) @ http://gamadu.com/
kul_th_las
Guest
« Reply #1 - Posted 2006-01-02 08:32:03 »

I would write it slightly different, but I think what you've got there is as simple as it gets when you're starting with a pair of (x, y) coordinates.

You could change your logic around a bit so you don't have so many if/then/else statements, but it doesn't look like you're doing any wasted work.
Online kevglass

JGO Kernel


Medals: 121
Projects: 23
Exp: 18 years


Coder, Trainee Pixel Artist, Game Reviewer


« Reply #2 - Posted 2006-01-02 14:05:32 »

Math.atan2() does this doesn't it?

Kev

Games published by our own members! Check 'em out!
Legends of Yore - The Casual Retro Roguelike
Offline woogley
« Reply #3 - Posted 2006-01-02 14:09:30 »

1  
2  
3  
protected double calcAngle(Point p1,Point p2) {
     return Math.atan2(p2.y-p1.y,p2.x-p1.x)*180.0/Math.PI;
}
Offline appel

JGO Wizard


Medals: 50
Projects: 4


I always win!


« Reply #4 - Posted 2006-01-02 14:31:16 »

Amazing, thanks kev and woogley. That was exactly the *simplicity* I was looking for  Cheesy

Check out the 4K competition @ www.java4k.com
Check out GAMADU (my own site) @ http://gamadu.com/
Pages: [1]
  ignore  |  Print  
 
 
You cannot reply to this message, because it is very, very old.

 

Add your game by posting it in the WIP section,
or publish it in Showcase.

The first screenshot will be displayed as a thumbnail.

CogWheelz (8 views)
2014-07-30 21:08:39

Riven (20 views)
2014-07-29 18:09:19

Riven (14 views)
2014-07-29 18:08:52

Dwinin (12 views)
2014-07-29 10:59:34

E.R. Fleming (32 views)
2014-07-29 03:07:13

E.R. Fleming (12 views)
2014-07-29 03:06:25

pw (42 views)
2014-07-24 01:59:36

Riven (42 views)
2014-07-23 21:16:32

Riven (29 views)
2014-07-23 21:07:15

Riven (30 views)
2014-07-23 20:56:16
HotSpot Options
by dleskov
2014-07-08 03:59:08

Java and Game Development Tutorials
by SwordsMiner
2014-06-14 00:58:24

Java and Game Development Tutorials
by SwordsMiner
2014-06-14 00:47:22

How do I start Java Game Development?
by ra4king
2014-05-17 11:13:37

HotSpot Options
by Roquen
2014-05-15 09:59:54

HotSpot Options
by Roquen
2014-05-06 15:03:10

Escape Analysis
by Roquen
2014-04-29 22:16:43

Experimental Toys
by Roquen
2014-04-28 13:24:22
java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!