Bezier Curve Generation

Bezier Curve Generation draws Bezier Curves on the screen This little snippet draws Bezier Curves on the screen. Copy and paste into the first frame of your file.

var mouseListener:Object = new Object();

this.createEmptyMovieClip("scene_mc", 1);
scene_mc._x = 0;
scene_mc._y = 0;
var control1_mc:MovieClip = scene_mc.createEmptyMovieClip("P0 -> P1", 2);
var control2_mc:MovieClip = scene_mc.createEmptyMovieClip("P2 -> P3", 3);
var curve_mc:MovieClip = scene_mc.createEmptyMovieClip("b_curve", 4);

var counter:Number = 0;
var point:Array = new Array(4);

mouseListener.onMouseDown = function() {
     switch(counter) {
          case 0:
          curve_mc.clear();
          control1_mc.clear();
          control2_mc.clear();
          control1_mc.moveTo(_xmouse, _ymouse);
          point[counter] = new Array(_xmouse, _ymouse);
          counter++;
          break;
          case 1:
          control1_mc.lineTo(_xmouse, _ymouse);
          point[counter] = new Array(_xmouse, _ymouse);
          counter++;
          break;
          case 2:
          control2_mc.moveTo(_xmouse, _ymouse);
          point[counter] = new Array(_xmouse, _ymouse);
          counter++;
          break;
          case 3:
          control2_mc.lineTo(_xmouse, _ymouse);
          point[counter] = new Array(_xmouse, _ymouse);
          bezier(point[3][0], point[3][1]);
          counter = 0;
          break;
     }
}

mouseListener.onMouseMove = function() {
     switch(counter) {
          case 1:
          control1_mc.clear();
          control1_mc.lineStyle(1, 0x000000, 100);
          control1_mc.moveTo(point[0][0], point[0][1]);
          control1_mc.lineTo(_xmouse, _ymouse);
          break;
          case 3:
          control2_mc.clear();
          control2_mc.lineStyle(1, 0x000000, 100);
          control2_mc.moveTo(point[2][0], point[2][1]);
          control2_mc.lineTo(_xmouse, _ymouse);
          bezier(_xmouse, _ymouse);
          break;
     }
}

Mouse.addListener(mouseListener);

function bezier(point3x:Number, point3y:Number) {
     curve_mc.clear();
     curve_mc.lineStyle(2, 0xff0000, 100);
     curve_mc.moveTo(point[0][0], point[0][1]);
     var t_div:Number = 1/20;
     for(var t:Number = t_div; t <= 1 + t_div; t += t_div) {
          var xt:Number = (((point[2][0] + 3 * (point[1][0] - point3x) - point[0][0]) * t + 3 * (point3x - 2 * point[1][0] + point[0][0])) * t + 3 * (point[1][0] - point[0][0])) * t + point[0][0];
          var yt:Number = (((point[2][1] + 3 * (point[1][1] - point3y) - point[0][1]) * t + 3 * (point3y - 2 * point[1][1] + point[0][1])) * t + 3 * (point[1][1] - point[0][1])) * t + point[0][1];
          curve_mc.lineTo(xt, yt);
     }
}