package {
          import flash.display.Sprite;
          import flash.display.StageAlign;
          import flash.display.StageScaleMode;
          import flash.events.Event;
  
          public class @ax-animation-ch16-Lines3D1 extends Sprite
          {
                  private var balls:Array;
                  private var numBalls:uint = 50;
                  private var fl:Number = 250;
                  private var vpX:Number = stage.stageWidth / 2;
                  private var vpY:Number = stage.stageHeight / 2;
                  
                  public function @ax-animation-ch16-Lines3D1()
                  {
                          init();
                  }
                  
                  private function init():void
                  {
                          stage.align = StageAlign.TOP_LEFT;
                          stage.scaleMode = StageScaleMode.NO_SCALE;
                          
                          balls = new Array();
                          for(var i:uint = 0; i < numBalls; i++)
                          {
                                  var ball:animation_ch16_Ball3D = new animation_ch16_Ball3D(5, 0);
                                  balls.push(ball);
                                  ball.xpos = Math.random() * 200 - 100;
                                  ball.ypos = Math.random() * 200 - 100;
                                  ball.zpos = Math.random() * 200 - 100;
                                  addChild(ball);
                          }
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
                  
                  private function onEnterFrame(event:Event):void
                  {
                          var angleX:Number = (mouseY - vpY) * .001;
                          var angleY:Number = (mouseX - vpX) * .001;
                          for(var i:uint = 0; i < numBalls; i++)
                          {
                                  var ball:animation_ch16_Ball3D = balls[i];
                                  rotateX(ball, angleX);
                                  rotateY(ball, angleY);
                                  doPerspective(ball);
                          }
                          graphics.clear();
                          graphics.lineStyle(0);
                          graphics.moveTo(balls[0].x, balls[0].y);
                          for(i = 1; i < numBalls; i++)
                          {
                                  graphics.lineTo(balls[i].x, balls[i].y);
                          }
                  }
                  
                  private function rotateX(ball:animation_ch16_Ball3D, angleX:Number):void
                  {
                          var cosX:Number = Math.cos(angleX);
                          var sinX:Number = Math.sin(angleX);
                          
                          var y1:Number = ball.ypos * cosX - ball.zpos * sinX;
                          var z1:Number = ball.zpos * cosX + ball.ypos * sinX;
                          
                          ball.ypos = y1;
                          ball.zpos = z1;
                  }
                  private function rotateY(ball:animation_ch16_Ball3D, angleY:Number):void
                  {
                          var cosY:Number = Math.cos(angleY);
                          var sinY:Number = Math.sin(angleY);
                          
                          var x1:Number = ball.xpos * cosY - ball.zpos * sinY;
                          var z1:Number = ball.zpos * cosY + ball.xpos * sinY;
                          
                          ball.xpos = x1;
                          ball.zpos = z1;
                  }
                  
                  private function doPerspective(ball:animation_ch16_Ball3D):void
                  {                        
                          if(ball.zpos > -fl)
                          {
                                  var scale:Number = fl / (fl + ball.zpos);
                                  ball.scaleX = ball.scaleY = scale;
                                  ball.x = vpX + ball.xpos * scale;
                                  ball.y = vpY + ball.ypos * scale;
                                  ball.visible = true;
                          }
                          else
                          {
                                  ball.visible = false;
                          }
                  }
          }
  }