Flash basic Theory Class chapter III Application of Trigonometry Ⅱ

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Linear vertical Motion

In the wave1.as file, a linear vertical motion is added, just to add some inspiration to our animation. The following is the code for this file:

package {
　import flash.display.Sprite;
　import flash.events.Event;
　public class Wave1 extends Sprite {
　 private var ball:Ball;
　 private var angle:Number = 0;
　 private var centerY:Number = 200;
　 private var range:Number = 50;
　 private var xspeed:Number = 1;
　 private var yspeed:Number = .05;
　 public function Wave1() {
　　 init();
　 }
　 private function init():void {
　　 ball = new Ball();
　　 addChild(ball);
　　 ball.x = 0;
　　 addEventListener(Event.ENTER_FRAME, onEnterFrame);
　 }
　 public function onEnterFrame(event:Event):void {
　　 ball.x += xspeed;
　　 ball.y = centerY + Math.sin(angle) * range;
　　 angle += yspeed;
　 }
　}
}

Heart Movement

Use sine as a tool, not just for controlling physical locations. In the pulse.as file, a value is used to influence the scaling of the ball to achieve a heartbeat effect, the code is as follows:

package {
　import flash.display.Sprite;
　import flash.events.Event;
　public class Pulse extends Sprite {
　 private var ball:Ball;
　 private var angle:Number = 0;
　 private var centerScale:Number = 1;
　 private var range:Number = .5;
　 private var speed:Number = .1;
　 public function Pulse() {
　　 init();
　 }
　 private function init():void {
　　 ball = new Ball();
　　 addChild(ball);
　　 ball.x = stage.stageWidth / 2;
　　 ball.y = stage.stageHeight / 2;
　　 addEventListener(Event.ENTER_FRAME, onEnterFrame);
　 }
　 public function onEnterFrame(event:Event):void {
　　 ball.scaleX = ball.scaleY = centerScale +Math.sin(angle) * range;
　　 angle += speed;
　 }
　}
}

The principle is the same, Centerscale represents the scaling ratio of 100%, range represents range, and speed represents speed. Not only that, sine wave is also applied in attributes such as alpha,rotation.