// 一种简单的树类
package {
import flash.display.Sprite;
public class Tree extends Sprite {
public var xpos:Number = 0;
public var ypos:Number = 0;
public var zpos:Number = 0;
public function Tree() {
init();
}
public function init():void {
graphics.lineStyle(0, 0x00ff00); // 树的颜色
graphics.lineTo(0, -140 - Math.random() * 20); // 树干
graphics.moveTo(0, -30 - Math.random() * 30);
graphics.lineTo(Math.random() * 80 - 40, // 随机生成的树枝
-100 - Math.random() * 40);
graphics.moveTo(0, -60 - Math.random() * 40);
graphics.lineTo(Math.random() * 60 - 30,
-110 - Math.random() * 20);
}
}
}
------------------------------------------------------------------------------
// 利用简单树组成的森林
package {
import flash.display.Sprite;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
[SWF(backgroundColor=0x000000)]; // 设置背景为黑色，但不知为什么无效
public class Trees extends Sprite {
private var trees:Array; // 存放所有的树
private var numTrees:uint = 100; // 定义100颗够了
private var fl:Number = 250; // 屏幕距离眼睛一般设置为200--300
private var vpX:Number = stage.stageWidth / 2; // 物体太小后消失点
private var vpY:Number = stage.stageHeight / 2;
private var floor:Number = 50; // 水平面高度
private var vz:Number = 0; // Z轴透视深度速度
private var friction:Number = 0.98; // 阻尼系数
public function Trees() {
init();
}
private function init():void {
trees = new Array();
for (var i:uint = 0; i < numTrees; i++) {
var tree:Tree = new Tree(); // 生成树
trees.push(tree);
tree.xpos = Math.random() * 2000 - 1000;
tree.ypos = floor;
tree.zpos = Math.random() * 10000;
addChild(tree); //
}
addEventListener(Event.ENTER_FRAME, onEnterFrame);
stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
}
private function onEnterFrame(event:Event):void {
for (var i:uint = 0; i < numTrees; i++) {
var tree:Tree = trees;
move(tree);
}
vz *= friction; // 阻尼后的Z轴方向的速度
sortZ(); // Z轴消隐
}
private function onKeyDown(event:KeyboardEvent):void { // 加减速控制
if (event.keyCode == Keyboard.UP) {
vz -= 1;
} else if (event.keyCode == Keyboard.DOWN) {
vz += 1;
}
}
private function move(tree:Tree):void {
tree.zpos += vz; // 更新移动距离(速度)
if (tree.zpos < -fl) { // 如果树走到眼睛后面，则移动到远处
tree.zpos += 10000;
}
if (tree.zpos > 10000 - fl) { // 如果树太远，大于屏幕外1000则移回
tree.zpos -= 10000;
}
var scale:Number = fl / (fl + tree.zpos); // 计算透视深度系数
tree.scaleX = tree.scaleY = scale;
tree.x = vpX + tree.xpos * scale;
tree.y = vpY + tree.ypos * scale;
tree.alpha = scale * .7 + .3; // 不同距离用不同的alpha混色，显示大气透视(朦胧感)
}
private function sortZ():void {
trees.sortOn("zpos", Array.DESCENDING | Array.NUMERIC);
for (var i:uint = 0; i < numTrees; i++) {
var tree:Tree = trees;
setChildIndex(tree, i);
}
}
}
}