Question

我试图在y轴上拖动一个精灵，但是根据触点在节点上的开始位置，使精灵“粘住”用户手指。精灵当前正在拖动，但似乎是将精灵的锚点捕捉到节点内的触摸位置。

我假设它与通过[touch locationInNode:selectedNode];获取节点内的位置有关，但我不确定从那里去哪里。

这是我目前的代码。

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    for (UITouch *touch in touches) {
        CGPoint location  = [touch locationInNode:self];
        SKNode *node = [self nodeAtPoint:location];
        CGPoint newPosition = CGPointMake(node.position.x, location.y);

        if ([node.name isEqualToString:self.selectedNode] ) {

            if (newPosition.y > 230) {
                newPosition.y = 230;
            }
            node.position = newPosition;
        }
    }
}

Answer 1

您需要根据节点上的当前触摸位置偏移newPosition。

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    for (UITouch *touch in touches) 
    {
        CGPoint location  = [touch locationInNode:self];
        SKNode *node = [self nodeAtPoint:location];


        if ([node.name isEqualToString:self.selectedNode] )
        {
            CGPoint previousLocation = [touch previousLocationInNode:self];
            float diff = location.y - previousLocation.y;
            CGPoint newPosition = CGPointMake(node.position.x, node.position.y + diff);


            if (newPosition.y > 230) {
                newPosition.y = 230;
            }
            node.position = newPosition;
        }
    }
}

Answer 2

有几种方法可以做到这一点。下面的示例代码跟踪用户的触摸位置，并在更新方法期间将精灵移动到该位置。您可以修改代码以仅在y轴或x轴上移动。

@implementation MyScene
{
    SKSpriteNode *object1;
    CGPoint destinationLocation;
}

-(id)initWithSize:(CGSize)size
{
    if (self = [super initWithSize:size])
    {
        [self createObject];
        destinationLocation = CGPointMake(300, 150);
    }
    return self;
}

-(void)createObject
{
     object1 = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(50, 50)];
     object1.position = CGPointMake(300, 150);
    [self addChild:object1];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    destinationLocation = [touch locationInNode:self.scene];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    destinationLocation = [touch locationInNode:self.scene];
}

-(void)update:(CFTimeInterval)currentTime
{
    float x = fabs(object1.position.x - destinationLocation.x);
    float y = fabs(object1.position.y - destinationLocation.y);

    float divider = 0;
    if(x > y)
    {
        divider = x;
    } else
    {
        divider = y;
    }

    float xMove = (x/divider)*8; // change number to increase or decrease speed
    float yMove = (y/divider)*8; // change number to increase or decrease speed

    if(object1.position.x > destinationLocation.x)
        object1.position = CGPointMake(object1.position.x-xMove, object1.position.y);

    if(object1.position.x < destinationLocation.x)
        object1.position = CGPointMake(object1.position.x+xMove, object1.position.y);

    if(object1.position.y > destinationLocation.y)
        object1.position = CGPointMake(object1.position.x, object1.position.y-yMove);

    if(object1.position.y < destinationLocation.y)
        object1.position = CGPointMake(object1.position.x, object1.position.y+yMove);
}

@end

根据触摸位置拖动SKSpriteNode

2 个答案: