ios – 使用SKPhysics(碰撞)拖动SKSpriteNode(跟随你的手指动作)

2019年8月4日 315次阅读

想要使用SKPhysics拖动SKSpriteNode(跟随你的手指动作)(启用碰撞)

2失败的解决方案

1)

a)解决方案：更改SKSpriteNode的位置

b)问题：当用户快速通过墙壁拖动spriteNode时,SKSpriteNode会“神奇地”穿过墙壁(物理似乎不起作用)

c)代码：

@property (nonatomic) CGPoint translationBy;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    [self selectNodeForTouch:positionInScene];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    CGPoint previousPosition = [touch previousLocationInNode:self];

    CGPoint translation = CGPointMake(positionInScene.x - previousPosition.x, positionInScene.y - previousPosition.y);

    [self panForTranslation:translation];
}

- (void)panForTranslation:(CGPoint)translation {
    CGPoint position = [_selectedNode position];
    if([[_selectedNode name] isEqualToString:PLAYER_NAME]) {
        [_selectedNode setPosition:CGPointMake(position.x + translation.x, position.y + translation.y)];
    }
}

2)在这里搜索后发现这个advice由@ LearnCocos2D“当你使用物理时,坚持通过力,冲动或直接改变体速来移动物理体.”所以我尝试过：

a)解决方案：在sprite节点上应用脉冲.

b)问题：即使我没有拖动精灵节点,精灵节点也会继续移动. (表现得像浮船.一旦拖动停止,精灵节点将停止;预计它会像汽车一样;一旦拖动开始,它将跟随手指.)

c)代码：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    [self selectNodeForTouch:positionInScene];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    CGPoint previousPosition = [touch previousLocationInNode:self];

    CGPoint translation = CGPointMake(positionInScene.x - previousPosition.x, positionInScene.y - previousPosition.y);

    CGVector forceVector = CGVectorMake(translation.x, translation.y);
    [self.player.physicsBody applyImpulse:forceVector];
    //[self.player.physicsBody setVelocity:CGVectorMake(0, 0)];

}

– >>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>

更新：

来自评论：
“i)您可以确定节点到手指位置的距离,然后在每次更新时设置速度：这样它将完全位于手指在下一帧的位置.ii)如果手指和节点位置相同,则会取消任何运动,否则节点将在执行所有物理碰撞时粘在你的手指上,并且在受阻的情况下将继续在物体和手指之间推动物体.

a)问题：如何禁用电影？

b)问题：精灵节点将通过轻微(意外)轻弹移动很远.

c)代码：

@property (nonatomic) CGPoint translationBy;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint positionInScene = [touch locationInNode:self];
    CGPoint previousPosition = [touch previousLocationInNode:self];
    //    1) You could determine the distance of the node to the finger location,

    CGPoint xyTranslation = CGPointMake(positionInScene.x - previousPosition.x, positionInScene.y - previousPosition.y);
    if (fabsf(positionInScene.x - previousPosition.x) < kPlayerMovementThreshold) {
        xyTranslation.x  = 0;
    }
    if (fabsf(positionInScene.y - previousPosition.y) < kPlayerMovementThreshold) {
        xyTranslation.y = 0;
    }
    self.translationBy = xyTranslation;
}

static const CGFloat kPlayerMovementSpeed = 55.0f;

static const CGFloat kPlayerMovementThreshold = 1.0f;

-(void)update:(CFTimeInterval)currentTime{
     // ii) then set the velocity every update: so that it will exactly be on the finger's position the next frame.

    CGFloat dx = self.translationBy.x*kPlayerMovementSpeed;
    CGFloat dy = self.translationBy.y*kPlayerMovementSpeed;
    CGVector velocityVector = CGVectorMake(dx,dy);
    [self.player.physicsBody setVelocity:velocityVector];
}

最佳答案 我做的是制作一个SKNode,我们称之为’a’,附带一个非常小的物理主体.这个新节点通过SKPhysicsJointSpring连接到我想要移动的节点,让我们称之为’b’.新节点a跟踪我的手指移动,弹簧确保目标节点b遵循该节点.因为节点b使用物理定位,所以碰撞检测按预期工作.

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