cocos2d使对象跟随触摸/手指 [英] cocos2d make object follow the touch/finger

问题描述

我用cocos2d做我的第一个应用程序，所以我在这里很新

I make my first app with cocos2d, so I am very new here

我的第一个问题：

我不会让物体（船）顺着我的手指。

I wont to make the object (boat) to follow my finger.

-(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]];
    }
} 

它确实可以跟随，但它并不是一成不变的。如果我快速移动手指，它就会停止，并且只有在我停止时才跟随。

It do follow but it is not fluid. If I move my finger quickly, it stops, and follow only if I stop.

第二个问题

如何计算2个点之间的距离。

How to calculate the distance between 2 points.

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

问题是，currentLocation在每次具有其他值时的每个点上都不恒定....为什么

The problem, currentLocation is not constant on each point it has every time other value.... why?

也许是因为我有滚动背景？

Maybe becouse I have a scrolling background??

推荐答案

您正在呼叫 [boat runAction：[CCMoveTo actionWithDuration：1 position：location]]; 每秒多次，这会导致多个 CCMoveTo 要同时运行的动作。这不是设计使用 cocos2d的操作工具的方式。

You are calling [boat runAction: [CCMoveTo actionWithDuration:1 position:location]]; multiple times per second, which causes multiple CCMoveTo actions to be running simultaneously. This is not how cocos2d's Action tools were designed to be used.

如果您希望船以您定义的较慢速度跟随触摸，则不能排队多个 CCMoveTo 响应 ccTouchMoved：的操作。

If you want the boat to follow touches at a slower speed defined by you, you cannot queue up multiple CCMoveTo actions in response to ccTouchMoved:.

相反，按下 UITouch 对象（或 NSValue 的 CGPoint 到 NSMutableArray 。然后定义一个回调函数，以使您的船在每次CCMoveTo完成后继续前进。

Instead, push the UITouch objects (or NSValues of the CGPoints) onto an NSMutableArray. Then define a callback function to keep your boat moving after each CCMoveTo completes.

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];
}

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