Question

感谢你的时间！

我正在用box2d做一个项目。当我第一次触摸屏幕时，会在box2d世界中创建一只鸟，如下所示

- (void)createBird
{    
//init bird
bird = [CCSprite spriteWithFile:@"bird.png"];
bird.scale = 23/[bird boundingBox].size.width;
bird.position = center;
[self addChild:bird z:12];
}

然后，如果触摸结束，那么鸟就会受力

    //add box2d body
    b2BodyDef birdBodyDef;
    birdBodyDef.type=b2_dynamicBody;
    birdBodyDef.userData = (__bridge void*)bird;
    birdBodyDef.position.Set(bird.position.x/PTM_RATIO,bird.position.y/PTM_RATIO);
    birdBody=world->CreateBody(&birdBodyDef);

    //create circle shape
    b2CircleShape birdShape;
    birdShape.m_radius=([bird boundingBox].size.width-6)/PTM_RATIO/2;

    // Create shape definitio and add to body
    b2FixtureDef birdFixtureDef;
    birdFixtureDef.shape=&birdShape;
    birdFixtureDef.density=1.6f;
    birdFixtureDef.friction=0.3f;
    birdFixtureDef.restitution=0.3f;
    birdFixture = birdBody -> CreateFixture(&birdFixtureDef);

    // Apply force
    b2Vec2 force = b2Vec2(-2.0f*distance,-2.0f*distance);
    birdBody->ApplyForce(force,birdBody->GetWorldCenter());
    birdBody->SetLinearDamping(0.2f);

然后，当我再次触摸屏幕时，将使用“createBird”方法创建另一只鸟。

我想在创建5秒后删除第一只鸟。但那时，“CCSprite * bird”和“b2Body * birdBody”将指向第二只鸟，那么如何删除第一只鸟呢？

谢谢！

Answer 1

我不确定我完全理解你的问题，但这可能有所帮助。在创建新鸟之前打电话。

if ( bird ) {

  id delayTimeAction = [CCDelayTime actionWithDuration:5.0];

  id removeMySprite = [CCCallFuncND actionWithTarget:bird   selector:@selector(removeFromParentAndCleanup:) data:(void*)NO];

  [bird runAction:[CCSequence actions: delayTimeAction, removeMySprite, nil]];

}

编辑：

初始化数组

NSMutableArray *birds = [NSMutableArray new];

然后在创建鸟类功能中调用它

[birds addObject:newBird];

if ( [birds count] > 1 ) {
    oldBird = [birds firstObject];
    //Call remove function on oldBird
    [birds removeObject:oldBird];
}

Answer 2

一种方法是给你的鸟牌，然后将它们保存到Nsmutuable词典中。继续遍历那个字典，然后在你的bool变量设置为destroy之后摧毁身体......

我使用类做了同样的事情....事实上，无论如何你都需要摧毁身体。（否则你将在以后遇到fps问题）

如何在延迟一段时间后删除sprite / b2body？

2 个答案: