SpriteKit 侧滚动不会更新 physicsWorld

Question

根据示例 here（Objective C 除外）和标准 Apple 文档，我发现 physicsWorld 在 myWorld 更新时不会更新其位置它的位置。我在我的 skView 上打开 showsPhysics 来验证这一点。请参阅这些屏幕截图。

在任何动议之前：稍微动一下后走得更远一点就在接触之前

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

- (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)];
        }
    }
}

有什么优雅的方法可以解决这个问题吗？到目前为止，我唯一的想法是在 centerOnNode 中包含更多代码，以重置 myWorld 中每个 physicsBody 的位置。

Answer 1

我注意到一旦猴子接触到，所有的物理体都会迅速回到它们正确的位置。但是，关节 anchorPoint 最终出现在错误的位置。

我在 GameScene.m 中添加了以下便捷方法。

-(CGPoint)convertSceneToFrameCoordinates:(CGPoint)scenePoint
{
    CGFloat xDiff = myWorld.position.x - self.position.x;
    CGFloat yDiff = myWorld.position.y - self.position.y;
    return CGPointMake(scenePoint.x + self.frame.size.width/2 + xDiff, scenePoint.y + self.frame.size.height/2 + yDiff);
}

我用这个方法来添加关节。它处理所有需要处理的坐标系转换，这些转换会导致此问题中提出的问题。比如我添加关节的方式

    CGPoint convertedRopePosition = [self convertSceneToFrameCoordinates:ropePhysicsBody.node.position];
    SKPhysicsJointPin *jointPin = [SKPhysicsJointPin jointWithBodyA:monkeyPhysicsBody bodyB:ropePhysicsBody anchor:convertedRopePosition];
    jointPin.upperAngleLimit = M_PI/4;
    jointPin.shouldEnableLimits = YES;
    [self.scene.physicsWorld addJoint:jointPin];

Answer 2

我不知道过去 2 年发生了什么变化，但这里的其他答案不再有效。相反，现在我将绳索段位置与其父级（完整绳索）的位置结合起来。所以我只是

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];

这是必需的，因为绳段位于绳索的全长下方，因此它的位置是相对于整条绳索而不是场景。

SpriteKit 侧滚动不会更新 physicsWorld

SpriteKit side scrolling doesn't update physicsWorld

ios

sprite-kit