ios - Sprite Kit - Sprite 和 Edge 碰撞时有很大的间隙 [见截图]

Question

正如您在下面的屏幕截图中看到的，圆（SKShapeNode）和线（也是 SKShapeNode）之间有很大的差距。

自然，这两个项目在碰撞时都应该接触。

这是我的代码：

- (void)createSceneContents
{
    [self setBackgroundColor:[SKColor blackColor]];

    //  Floor
    //
    SKShapeNode *floorShapeNode = [SKShapeNode node];
    CGFloat threeQuartersDown = CGRectGetMidY(self.frame) * 0.5f;
    CGPoint floorFromPoint = CGPointMake(CGRectGetMinX(self.frame), threeQuartersDown);
    CGPoint floorToPoint = CGPointMake(CGRectGetMaxX(self.frame), threeQuartersDown);

    CGMutablePathRef floorLinePath = CGPathCreateMutable();
    CGPathMoveToPoint(floorLinePath, NULL, floorFromPoint.x, floorFromPoint.y);
    CGPathAddLineToPoint(floorLinePath, NULL, floorToPoint.x, floorToPoint.y);
    [floorShapeNode setPath:floorLinePath];

    [floorShapeNode setPhysicsBody:[SKPhysicsBody bodyWithEdgeFromPoint:floorFromPoint toPoint:floorToPoint]];
    [floorShapeNode setStrokeColor:[SKColor whiteColor]];
    [floorShapeNode setLineWidth:0.5f];

    [self addChild:floorShapeNode];

    //  Player
    //
    [self setPlayerNode:[BZPlayerNode node]];
    [self.playerNode setPhysicsBody:[SKPhysicsBody bodyWithCircleOfRadius:(CGRectGetWidth(self.playerNode.frame) / 2.0f)]];
    [self.playerNode.physicsBody setDynamic:YES];
    [self.playerNode setPosition:CGPointMake(CGRectGetMidX(self.frame) - CGRectGetMidX(self.playerNode.frame), CGRectGetMidY(self.frame) - CGRectGetMidX(self.playerNode.frame) + 100.0f)];

    [self addChild:self.playerNode];
}

以及 SKShapeNode 的 +node 方法：

+ (instancetype)node
{
    BZPlayerNode *playerNode = [super node];

    if (playerNode) {
        [playerNode setFillColor:[SKColor whiteColor]];
        [playerNode setPath:CGPathCreateWithEllipseInRect(CGRectMake(0.0f, 0.0f, 80.0f, 80.0f), NULL)];
    }

    return playerNode;
}

有谁知道我哪里出错了？

谢谢