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  Simpler way to calculate angle between two points?  (Read 3231 times)
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Offline appel

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« Posted 2006-01-02 06:20:01 »

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

I'm currently using this method:

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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?

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