ios - 根据触摸位置拖动 SKSpriteNode

Question

我试图在 y 轴上拖动 Sprite ，但根据节点上开始触摸的位置，使 Sprite “粘附”到用户的手指上。 Sprite 目前正在拖动，但它似乎正在将 Sprite 的 anchor 捕捉到节点内的触摸位置。

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

这是我当前的代码。

-(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来偏移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;
        }
    }
}