104 lines
2.5 KiB
Markdown
104 lines
2.5 KiB
Markdown
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碰撞检测，判断显示对象是否与一点相交。
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矩形碰撞检测，是判断显示对象的包围盒是否与一点相交。
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Egret 提供 `hitTestPoint()` 方法进行碰撞检测，矩形碰撞检测的用法为：
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```javascript
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var isHit:boolean = shp.hitTestPoint( x: number, y:number );
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```
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`shp` 是待检测的显示对象，(x, y)是待检测的点的位置。如果发生碰撞，则方法返回 `true`,如果没有发生碰撞，则返回 `false`。
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* 示例代码1：
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```javascript
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class HitTest extends egret.DisplayObjectContainer
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{
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public constructor()
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{
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super();
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this.addEventListener(egret.Event.ADDED_TO_STAGE,this.onAddToStage,this);
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}
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private onAddToStage(event:egret.Event)
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{
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this.drawText();
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var shp:egret.Shape = new egret.Shape();
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shp.graphics.beginFill( 0xff0000 );
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shp.graphics.drawRect( 0,0,100,100);
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shp.graphics.endFill();
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shp.width = 100;
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shp.height = 100;
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this.addChild( shp );
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var isHit:boolean = shp.hitTestPoint( 10, 10 );
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this.infoText.text = "isHit: " + isHit;
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}
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private infoText:egret.TextField;
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private drawText()
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{
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this.infoText = new egret.TextField();
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this.infoText.y = 200;
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this.infoText.text = "isHit";
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this.addChild( this.infoText );
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}
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}
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```
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编译调试后，效果如下图：
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文本中返回碰撞的结果，显示为 `true`，表示发生了碰撞。
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* 示例代码2：
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```javascript
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class HitTest extends egret.DisplayObjectContainer
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{
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public constructor()
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{
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super();
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this.addEventListener(egret.Event.ADDED_TO_STAGE,this.onAddToStage,this);
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}
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private onAddToStage(event:egret.Event)
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{
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this.drawText();
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var shp:egret.Shape = new egret.Shape();
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shp.graphics.beginFill( 0xff0000 );
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shp.graphics.drawCircle( 0, 0, 20);
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shp.graphics.endFill();
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shp.width = 100;
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shp.height = 100;
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this.addChild( shp );
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var isHit:boolean = shp.hitTestPoint( 25, 25 );
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this.infoText.text = "isHit: " + isHit;
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}
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private infoText:egret.TextField;
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private drawText()
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{
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this.infoText = new egret.TextField();
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this.infoText.y = 200;
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this.infoText.text = "isHit: ";
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this.addChild( this.infoText );
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}
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}
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```
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编译调试后，效果如下图：
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文本中返回碰撞的结果，显示为 `true`，表示发生了碰撞。
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>注意：该点并未与红色圆形直接相交，而是与红色圆形的包围盒相交。
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