无法弄清楚为什么球物体会直接穿过线[2]，而它会从所有其他物体反弹。我在下面有两个课程；创建线条的主类以及球的一些碰撞和运动代码，以及球的类。我在主类的行上方添加了一个注释，该注释与不交互的行有关。当程序运行时，它会使用一些基于距离的碰撞代码从所有行反弹 - 但直接穿过其中一行 - 在第 [2] 行的数组中创建的行
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.geom.Rectangle;
public class MultiAngleBounce extends Sprite
{
private var ball:Ball;
private var lines:Array;
private var numLines:uint = 6;
private var gravity:Number = 0.3;
private var bounce:Number = -0.6;
public function MultiAngleBounce()
{
init();
}
private function init():void
{
ball = new Ball(20);
addChild(ball);
ball.x = 100;
ball.y = 100;
//create five lines
lines = new Array();
for(var i:uint = 0; i < numLines; i++)
{
var line:Sprite = new Sprite();
line.graphics.lineStyle(1);
line.graphics.moveTo(-50, 0);
line.graphics.lineTo(50, 0);
addChild(line);
lines.push(line);
}
lines[0].x = 100;
lines[0].y = 100;
lines[0].rotation = 30;
lines[1].x = 100;
lines[1].y = 230;
lines[1].rotation = 50;
//why does this one get ignored
lines[2].x = 250;
lines[2].y = 180;
lines[2].rotation = -30;
lines[3].x = 150;
lines[3].y = 330;
lines[3].rotation = 10;
lines[4].x = 230;
lines[4].y = 250;
lines[4].rotation = -30;
lines[5].x = 300;
lines[5].y = 350;
lines[5].rotation = -20;
addEventListener(Event.ENTER_FRAME, onEnterFrame);
}
private function onEnterFrame(event:Event):void
{
//normal motion code
ball.vy += gravity;
ball.x += ball.vx;
ball.y += ball.vy;
//bounce off ceiling, floor, walls
if(ball.x + ball.radius > stage.stageWidth)
{
ball.x = stage.stageWidth - ball.radius;
ball.vx *= bounce;
}
else if(ball.x - ball.radius < 0)
{
ball.x = ball.radius;
ball.vx *= bounce;
}
if(ball.y + ball.radius > stage.stageHeight)
{
ball.y = stage.stageHeight - ball.radius
ball.vy *= bounce;
}
else if(ball.y - ball.radius < 0)
{
ball.y = ball.radius;
ball.vy *= bounce;
}
//check each line
for(var i:uint = 0; i < numLines; i++)
{
checkLine(lines[i]);
}
}
private function checkLine(line:Sprite):void
{
//get the bounding box of the line
var bounds:Rectangle = line.getBounds(this);
if(ball.x > bounds.left && ball.x < bounds.right)
{
//get angle, sine and cosine
var angle:Number = line.rotation * Math.PI / 180;
var cos:Number = Math.cos(angle);
var sin:Number = Math.sin(angle);
//get position of ball, relative to line
var x1:Number = ball.x - line.x;
var y1:Number = ball.y - line.y;
//rotate coordinates
var y2:Number = cos * y1 - sin * x1;
//rotate velocity
var vy1:Number = cos * ball.vy - sin * ball.vx;
//perform bounce with rotated values
if(y2 > -ball.height / 2 && y2 < vy1)
{
//rotate coordinates
var x2:Number = cos * x1 + sin * y1;
//rotate velocity
var vx1:Number = cos * ball.vx + sin * ball.vy;
y2 = -ball.height / 2;
vy1 *= bounce;
//rotate everything back;
x1 = cos * x2 - sin * y2;
y1 = cos * y2 + sin * x2;
ball.vx = cos * vx1 - sin * vy1;
ball.vy = cos * vy1 + sin * vx1;
ball.x = line.x + x1;
ball.y = line.y + y1;
}
}
}
}
}
package
{
import flash.display.Sprite;
public class Ball extends Sprite
{
public var radius:Number;
private var color:uint;
public var internalAngle:Number;
public var internalRadius:Number;
internal var vx:Number = 0;
internal var vy:Number = 0;
public function Ball(radius:Number = 40, color:uint = 0xff0000)
{
this.radius = radius;
this.color = color;
init();
}
public function init():void {
graphics.beginFill(color);
graphics.drawCircle(0, 0, radius);
graphics.endFill();
}
}
}