here what i've found from an existing thread,
http://processing.org/discourse/yabb_beta/YaBB.cgi?board=OpenGL;action=display;num=1206925856

can't seem to crack this one.
here is what i have so far.
trying to orientate the bat to point the direction it is travelling.

Vec3D out, up, right;



up    = new Vec3D( 0, 1, 0 );
out   = locs[ 0 ].sub( locs[ 1 ] ).normalize();
up    = up.cross( out ).normalize();
right = out.cross( up ).normalize();



float[] m;
m = new float[]
 {
   right.x, up.x, out.x, 0,
   right.y, up.y, out.y, 0,
   right.z, up.z, out.z, 0,
   0,
    0,
  0,
 1
 };

FloatBuffer rotMatrix;
rotMatrix = ByteBuffer.allocateDirect(4 * 4 * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();



rotMatrix.put( m );



rotMatrix.flip();

gl.glPushMatrix();
gl.glMultMatrixf( rotMatrix );

// draw.

gl.glPopMatrix();