SpriteKit侧滚动不会更新physicsWorld [英] SpriteKit side scrolling doesn't update physicsWorld

问题描述

按照示例此处（除了目标C）和标准的Apple文档，我发现 physicsWorld 在 myWorld 时不会更新其位置更新其立场。我在我的skView上打开 showsPhysics 来验证这一点。请参阅这些屏幕截图。

Following the example here (except in Objective C) and the standard Apple documentation, I discovered that the physicsWorld doesn't update its positions when myWorld updates its position. I turned on showsPhysics on my skView to verify this. See these screenshots.

在任何动议之前：

经过一点动作

再远一点
< img src =https://i.imgur.com/xnyhD1z.jpgalt =screen 3>
在联系

Before any motion: After a little motion Getting a little farther And just before contact

这是我的代码 myWorld 。大部分长度是由于我在处理边缘限制时非常冗长。

Here's my code for centering myWorld. Most of the length is due to me being extremely verbose in dealing with the edge limits.

- (void)centerOnNode:(SKNode *)monkeyNode
{
    CGPoint monkeyPosition = monkeyNode.position;

    // Check if monkey died
    if (monkeyPosition.y < myWorld.frame.origin.y - sceneHeight/2) {
        [self monkeyDied];
    }

    // Check if monkey won
    if (monkeyPosition.x > skyFarRightSide.x) {
        [self monkeyWon:monkeyNode];
    }

    // Define limits
    CGFloat scrollTopLimit = skyFarTopSide.y - sceneHeight/2;
    CGFloat scrollBottomLimit = 0;
    CGFloat scrollLeftLimit = 0;
    CGFloat scrollRightLimit = skyFarRightSide.x - sceneWidth/2;

    // Normal (no limits hit) scrolling
    if (monkeyPosition.x > scrollLeftLimit && monkeyPosition.x < scrollRightLimit && monkeyPosition.y > scrollBottomLimit && monkeyPosition.y < scrollTopLimit) {
        [myWorld setPosition:CGPointMake(-monkeyPosition.x, -monkeyPosition.y)];
    }

    // At far left scrolling
    if (monkeyPosition.x < scrollLeftLimit) {
        // No y limits hit
        if (monkeyPosition.y > scrollBottomLimit && monkeyPosition.y < scrollTopLimit) {
            [myWorld setPosition:CGPointMake(0, -monkeyPosition.y)];
        }

        // Bottom limit hit
        if (monkeyPosition.y < scrollBottomLimit) {
            [myWorld setPosition:CGPointMake(0, 0)];
        }

        // Top limit hit
        if (monkeyPosition.y > scrollTopLimit) {
            [myWorld setPosition:CGPointMake(0, -scrollTopLimit)];
        }
    }

    // At far right scrolling
    if (monkeyPosition.x > scrollRightLimit) {
        // No y limits hit
        if (monkeyPosition.y > scrollBottomLimit && monkeyPosition.y < scrollTopLimit) {
            [myWorld setPosition:CGPointMake(-scrollRightLimit, -monkeyPosition.y)];
        }

        // Bottom limit hit
        if (monkeyPosition.y < scrollBottomLimit) {
            [myWorld setPosition:CGPointMake(-scrollRightLimit, 0)];
        }

        // Top limit hit
        if (monkeyPosition.y > scrollTopLimit) {
            [myWorld setPosition:CGPointMake(-scrollRightLimit, -scrollTopLimit)];
        }
    }

    // At far bottom scrolling
    if (monkeyPosition.y < scrollBottomLimit) {
        // No x limits hit
        if (monkeyPosition.x > scrollLeftLimit && monkeyPosition.x < scrollRightLimit) {
            [myWorld setPosition:CGPointMake(-monkeyPosition.x, 0)];
        }

        // Left limit hit
        if (monkeyPosition.x < scrollLeftLimit) {
            [myWorld setPosition:CGPointMake(0, 0)];
        }

        // Right limit hit
        if (monkeyPosition.x > scrollRightLimit) {
            [myWorld setPosition:CGPointMake(-scrollRightLimit, 0)];
        }
    }

    // At far top scrolling
    if (monkeyPosition.y > scrollTopLimit) {
        // No x limits hit
        if (monkeyPosition.x > scrollLeftLimit && monkeyPosition.x < scrollRightLimit) {
            [myWorld setPosition:CGPointMake(-monkeyPosition.x, -scrollTopLimit)];
        }

        // Left limit hit
        if (monkeyPosition.x < scrollLeftLimit) {
            [myWorld setPosition:CGPointMake(0, -scrollTopLimit)];
        }

        // Right limit hit
        if (monkeyPosition.x > scrollRightLimit) {
            [myWorld setPosition:CGPointMake(-scrollRightLimit, -scrollTopLimit)];
        }
    }
}

有没有一种优雅的方式解决这个问题？到目前为止，我唯一的想法是在 centerOnNode 中包含更多代码，用于重置<$ c $中每个 physicsBody 的位置C> myWorld 。

Is there an elegant way to fix this? So far my only idea is to include more code in centerOnNode that resets the positions of every physicsBody in myWorld.

推荐答案

我不知道过去两年有什么变化，但这里的另一个答案已不再适用了。相反，现在我将绳段位置与其父级（完整绳索）组合在一起。所以我只做

I don't know what's changed in the last 2 years, but the other answer here didn't work anymore. Instead, now I combine the rope segments position with its parent's (the full rope). So I just do

CGPoint convertedRopePosition = CGPointMake(ropePhysicsBody.node.parent.position.x + ropePhysicsBody.node.position.x, ropePhysicsBody.node.parent.position.y + ropePhysicsBody.node.position.y);
SKPhysicsJointPin *jointPin = [SKPhysicsJointPin jointWithBodyA:monkeyPhysicsBody bodyB:ropePhysicsBody anchor:convertedRopePosition];

这是必要的，因为绳索段位于绳索的整个长度下，所以它的位置是相对于完整的绳索而不是场景。

This is needed because the rope segment is placed under the full length of the rope, so it's position is relative to the full rope rather than the scene.

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