BitmapData冲突
BitmapData冲突
提问于 2012-04-25 13:48:22
我一直在尝试使用BitmapData进行碰撞检测，但到目前为止都失败了，我不知道为什么。代码会编译，但不会做任何事情(当它应该打印"hit“时)。有谁可以帮我？
package
{
import flash.events.KeyboardEvent;
import flash.events.Event;
import flash.display.MovieClip;
import flash.ui.Keyboard;
import flash.display.BitmapData;
import flash.geom.Point;
public class Main extends MovieClip
{
private var spd:int = 5;
private var pressedKeys:Object = {};
private var bgMask:BitmapData;
private var plMask:BitmapData;
private var wall:Wall = new Wall();
public function Main()
{
var bgBitMapData:BitmapData = new BitmapData(bg.width,bg.height,true,0);
bgMask = bgBitMapData.clone();
wall.x = bg.x;
wall.y = bg.y;
bgMask.draw( wall );
var plBitMapData:BitmapData = new BitmapData(pl.width,bg.height,true,0);
plMask = bgBitMapData.clone();
bgMask.draw( pl );
stage.addEventListener(KeyboardEvent.KEY_DOWN,this.keyPressHandler);
stage.addEventListener(KeyboardEvent.KEY_UP,this.keyPressHandler);
stage.addEventListener(Event.ENTER_FRAME,this.gameLoop);
}
public function keyPressHandler( evt:KeyboardEvent ):void
{
if (evt.type == KeyboardEvent.KEY_DOWN)
{
pressedKeys[evt.keyCode] = 1;
}
else
{
delete pressedKeys[ evt.keyCode ];
}
}
public function inputHandler():void
{
var moveXBy:int;
var moveYBy:int;
if (pressedKeys[Keyboard.J])
{
moveXBy -= spd;
}
if (pressedKeys[Keyboard.K])
{
moveYBy += spd;
}
if (pressedKeys[Keyboard.L])
{
moveXBy += spd;
}
if (pressedKeys[Keyboard.I])
{
moveYBy -= spd;
}
pl.x += moveXBy;
pl.y += moveYBy;
}
public function playerWallCollision():void
{
if ( plMask.hitTest( new Point( wall.x, wall.y ), 1, bgMask, new Point( pl.x, pl.y ), 1))
{
trace( "hit" );
}
}
public function gameLoop( evt:Event ):void
{
wallUpdate();
inputHandler();
playerWallCollision();
}
private function wallUpdate()
{
wall.x = bg.x;
wall.y = bg.y;
}
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2012-04-25 16:03:20
就这个脚本告诉我的，在这几行之后：
var bgBitMapData:BitmapData = new BitmapData(bg.width,bg.height,true,0);
// bgBitMapData is an empty BMP at this point cause its just freshly instanciated
bgMask = bgBitMapData.clone();
wall.x = bg.x;
wall.y = bg.y;
bgMask.draw( wall );
var plBitMapData:BitmapData = new BitmapData(pl.width,bg.height,true,0);
// no idea y you make this plBitMapData anyway
plMask = bgBitMapData.clone();
// now you clone the empty bgBitMapData to be plMask
bgMask.draw( pl );plMask永远不会充满任何东西！因此，与空的BitmapData相比，应该总是返回false。
因此，什么时候应该输出hit - never的答案;)
作为附注，试着让它更具可读性。1.每到一处写一条评论，你的意图是什么；2.采取直接的方法：
var bgBitMapData:BitmapData = new BitmapData(bg.width,bg.height,true,0);
bgMask = bgBitMapData.clone();
// this position seems just wrong to me wall.x or wall.y do not effect the draw so keep it somewhere else... since you will copy the inside of wall
wall.x = bg.x;
wall.y = bg.y;
bgMask.draw( wall );对我来说，它应该是这样的：
// placing a wall to new / init coordinates
wall.x = bg.x;
wall.y = bg.y;
// drawing wall on bgMask for hittesting against player or what ever you intende here
bgMask = new BitmapData(bg.width,bg.height,true,0);
bgMask.draw( wall );页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/10310005
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