import flash.geom.Point;
import flash.display.Shape;
import flash.geom.Matrix;

var p1:Point = new Point(100,100);
var p2:Point = new Point(300,300);

var gFreq = 5; // frequency
var gAmp = 20; // amplitude in pixels

function sineTo(p1:Point, p2:Point, freq:Number, amp:Number):Shape {
    var d = Math.sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.x-p2.y));
    var a = Math.atan2(p2.y-p1.y,p2.x-p1.x);
    var sh:Shape = new Shape();
    sh.graphics.moveTo(0,0);
    sh.graphics.lineStyle(3,0xff0000);
    for (var i = 0; i <= d; i++) {
        sh.graphics.lineTo(i,Math.sin(i*2*Math.PI*freq/d)*amp);
    }
    var m:Matrix = sh.transform.matrix.clone();
    m.rotate(a);
    m.translate(p1.x,p1.y);
    sh.transform.matrix = m;
    return sh;
}
addChild(sineTo(p1,p2,gFreq,gAmp));