Curve Drawing Problem

programming flash
1

I’m trying to draw a curve that represents the projected trajectory of the ship at current conditionshere’s my code:

function trajectoryMapping():void
{
var newX:Number; var oldX:Number;
var newY:Number;
var oldY:Number;
var trajectoryArray:Array = new Array;
var trajectoryPoint:TrajectoryPoint;
var trajYVel:Number = _model.yVel;
var trajXVel:Number = _model.xVel;
var trajGravity:Number = _model.gravity;

   trajCurve.graphics.clear();                //clear curve for redraw
trajCurve.graphics.lineStyle(2, 0x876CD0);
trajCurve.graphics.moveTo(-40, -30);//this should start the line at the ship

    oldX = 220;//starting x & y
oldY = 190;

   trajCurve.graphics.moveTo(trajectoryArray[1].xPoint, trajectoryArray[1].yPoint);

if (_model.xVel == 0 && _model.yVel == 0)
{
//trajCurve.graphics.lineTo( -40, -30);
}
else
{
//line.graphics.lineTo(( -40 + (_model.xVel * magnitude)), ( -30 + (_model.yVel * magnitude)));

trajCurve.graphics.curveTo(trajectoryArray[15].xPoint, trajectoryArray[15].yPoint,trajectoryArray[30].xPoint, trajectoryArray[30].yPoint);

//GraphicsUtil.drawArrow(trajCurve.graphics,new Point(-40,-30),new Point(( -40 + (_model.xVel * magnitude)),( -30 + (_model.yVel * magnitude))), style );
}
//trajCurve.x = -40;
//trajCurve.y = -30;

addChild(trajCurve);

}
(Sorry code block wasn’t working???)

and below is my result. The straight purple line is supposed to be my curve.