ios - cocos2d使对象跟随触摸/手指

Question

我用 cocos2d 制作了我的第一个应用程序，所以我在这里很新

我的第一个问题:

我不会让物体(船)跟随我的手指。

-(void) ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event
{
    CGPoint location = [self convertTouchToNodeSpace: touch];
    NSLog(@"location X: %f", location.x);
    NSLog(@"location Y: %f", location.y);


    if(startGameButtonIsPressed == YES) {
        [boat runAction: [CCMoveTo actionWithDuration:1 position:location]];
    }
} 

它确实遵循，但并不流畅。如果我快速移动手指，它就会停止，只有当我停止时它才会跟随。

第二个问题

如何计算两点之间的距离。

CGPoint currentLocation = ccp(boat.position.x, boat.position.y);    
float distanceApart = ccpDistance(currentLocation, location);

问题是，currentLocation 在每次具有其他值的每个点上都不是恒定的......为什么？

也许是因为我有滚动背景？？

Answer 1

您每秒多次调用 [boat runAction: [CCMoveTo actionWithDuration:1position:location]]; ，这会导致多个 CCMoveTo 操作同时运行。这不是cocos2d 的操作工具的设计用途。

如果您希望船以您定义的较慢速度跟随触摸，则无法将多个 CCMoveTo 操作排队以响应 ccTouchMoved:。

相反，将 UITouch 对象(或 CGPoint 的 NSValue)推送到 NSMutableArray 上。然后定义一个回调函数，让您的船在每个 CCMoveTo 完成后保持移动。

示例代码:

//...defined elsewhere, e.g. your header file:
    #define kBoatMoveTag 123

    NSMutableArray *touchQueue; //treat the array like a queue.
                                //don't forget to alloc it before using.


-(void) ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event
{
    CGPoint location = [self convertTouchToNodeSpace: touch];
    NSLog(@"location X: %f", location.x);
    NSLog(@"location Y: %f", location.y);

    [touchQueue insertObject:[NSValue valueWithCGPoint:location] atIndex:0];
    [self continueBoatMovement];
}

-(void)continueBoatMovement {
    //if no queued point, or boat is already moving...
    if(touchQueue.count < 1 || [boat getActionByTag:kBoatMoveTag]) {
        return; //dont do anything 
    }

    NSValue valueOfPt = [touchQueue lastObject];
    [touchQueue removeLastObject];
    CGPoint newPt = [valueOfPt CGPointValue];
    float distance = ccpDistance(boat.position, newPt);
    float duration = distance / boatSpeed; //you must define boatSpeed somewhere

    CCMoveTo *move = [CCMoveTo actionWithDuration:duration position:newPt];

    CCSequence *moveSeq = [CCSequence actionOne:move two:[CCCallFunc actionWithTarget:self selector:@selector(continueBoatMovement)]];
    moveSeq.tag = kBoatMoveTag;
    [boat runAction:moveSeq];
}