Fix Polygon Vertexorder

[serthy]

Sanibonani =)

I have an array of n unsorted points (x,y,z).
These vertices will create a !convex! polygon.
Now I need your help to create an indexlist of these vertices in a sorted way:

Example:

5 points in 3d space: ( A , B , D , C )

	A      B






	C      D

connect them in the unsorted order as they are:

	A------B
	 \    /
	  \  /
	   \/
	   /\
	  /  \
	 /    \
	C------D

now sort them (counter-)clock wise:

	A      B






	D      C

and connect them again: ( A , B , C , D )

	A------B
	|      |
	|      |
	|      |
	|      |
	|      |
	|      |
	C------D

I am currently going over a dotProduct from the center of the polygon, but stucked there...
Maybe arcTan( x / y ) works!?

		sortVertsOnPoly( verts , center )
{
    dots = [];
    idx = [];

    for( i = 0 ; i < verts.size ; i++ )
    {
        v1 = verts[i];                //catch current vert
        v2 = verts[( i + 1 ) % verts.size];    //catch next vert to compare to

        v1 -= center;    //calculate current directions
        v2 -= center;

        dots[i] = ( v1[0] * v2[1] - v1[1] * v2[0] ); //calculate the dot(2D)
        idx[i] = i;    //store the index-information in a different array
    }

    //sort them by their dot-value
    for( i = dots.size ; i > 1 ; i-- )
    {
        for( j = 0 ; j < i - 1 ; j++ )
        {
            if( dots[i] > dots[i + 1] )    
            {
                t = dots[i];    //swap
                dots[i] = dots[i + 1];
                dots[i + 1] = t;

                t = idx[i];        //also swap the index array
                idx[i] = idx[i + 1];
                idx[i + 1] = t;
            }
        }
    }

    return idx;    //return sorted index array
} 
	

EDIT:

or just get vertex #1 as reference and calculate all other angles and compare them:
guess this woll work also... geez, why i didnt get this in my first toughts?!

		    dirs = [];
    dirs[0] = 0;
    dir = vectorNormalize( verts[0] - center );

    for( i = 1 ; i < verts.size ; i++ )
    {
        dirs[i] = aCos( vectorDot( dir , vectorNormalize( verts[i] - center ) ) );
        idx[i] = i;
    } 
	

EDIT: dont mind, im confused, the dot is the almost angle ~.~