大家好,我有一个问题,不知道如何解决它:(有人可以告诉我怎么做吗?
构造函数必须是实例方法。
所以这是我的代码:
package
{
import com.coreyoneil.collision.CollisionList;
import flash.events.Event;
import flash.display.Sprite;
public class terrain extends Sprite
{
private var wheel:Ball;
private var collisionList:CollisionList;
private var speed:Number;
private const GRAVITY:Number = .75;
private const FRICTION:Number = .98;
private const IMMOVABLE:Number = 10000;
public function terrain():void
{
if(stage == null)
{
addEventListener(Event.ADDED_TO_STAGE, init, false, 0, true);
addEventListener(Event.REMOVED_FROM_STAGE, clean, false, 0, true);
}
else
{
init();
}
}
private function init(e:Event = null):void
{
collisionList = new CollisionList(terrain);
wheel = new wheel(10);
wheel.mass = IMMOVABLE * 2;
addChild(wheel);
collisionList.addItem(wheel);
wheel.x = 30;
wheel.y = 10;
speed = 0;
terrain.graphics.lineStyle(15);
addEventListener(Event.ENTER_FRAME, updateScene);
}
private function updateScene(e:Event):void
{
var collisions:Array = collisionList.checkCollisions();
if(collisions.length)
{
var collision:Object = collisions[0];
var angle:Number = collision.angle;
var overlap:int = collision.overlapping.length;
var sin:Number = Math.sin(angle);
var cos:Number = Math.cos(angle);
var vx0:Number = wheel.vx * cos + wheel.vy * sin;
var vy0:Number = wheel.vy * cos - wheel.vx * sin;
// Unlike the other examples, here I'm choosing to calculate the amount
// of bounce based on the objects' masses, with a default mass of 10000 (IMMOVABLE)
// being used for the drawing the wheel is colliding with. As such, the only
// real variable in play here is the current vector of the wheel.
vx0 = ((wheel.mass - IMMOVABLE) * vx0) / (wheel.mass + IMMOVABLE);
wheel.vx = vx0 * cos - vy0 * sin;
wheel.vy = vy0 * cos + vx0 * sin;
wheel.vx -= cos * overlap /wheel.radius;
wheel.vy -= sin * overlap / wheel.radius;
wheel.vx += speed;
}
trace("down");
wheel.vy += GRAVITY;
wheel.vy *= FRICTION;
wheel.vx *= FRICTION;
wheel.x += wheel.vx;
wheel.y += wheel.vy;
if(wheel.x > stage.stageWidth) wheel.x = stage.stageWidth;
if(wheel.x < 0) wheel.x = 0;
if(wheel.y > stage.stageHeight - (wheel.height >> 1))
{
wheel.y = 10;
wheel.x = 30;
wheel.vx = wheel.vy = 0;
}
}
private function clean(e:Event):void
{
removeEventListener(Event.ENTER_FRAME, updateScene);
}
}
}
代码中有一些注释..请忽略它,我使用了示例。