为什么zRotation后节点会按Y轴变化答案

【问题标题】：Why does node is changing by Y axis after zRotation为什么zRotation后节点会按Y轴变化
【发布时间】：2014-12-15 23:57:40
【问题描述】：

我有一根棍子，它在触摸时会变高，在触摸结束后会随着持续时间旋转 90 度。所以我决定不使用这个关节销，所有的都没有物理，但我不能成功地将我的棒添加到平台上，它会旋转 90 度并从另一侧固定到平台上，所以我需要的是图片上：

http://prntscr.com/5hau7p

我的代码在那里，我正在制作平台锚，坚持...

self.p_currentPlatform = [SKShapeNode shapeNodeWithRect:CGRectMake(-100/2, -320/2, 100, 320)];
self.p_currentPlatform.position = CGPointMake(50, 160);
self.p_currentPlatform.strokeColor = [SKColor grayColor];
self.p_currentPlatform.fillColor = [SKColor yellowColor];
self.p_currentPlatform.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:_p_currentPlatform.frame.size];
self.p_currentPlatform.physicsBody.dynamic = NO;
[self addChild:self.p_currentPlatform atWorldLayer:VZWorldLayerCharacter];


self.anchor = [SKSpriteNode spriteNodeWithColor:[UIColor blackColor] size:CGSizeMake(1, 1)];
CGPoint pos = CGPointMake(_p_currentPlatform.frame.origin.x + _p_currentPlatform.frame.size.width,
                               _p_currentPlatform.frame.size.height);
self.anchor.position = pos;
self.anchor.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:.1f];
self.anchor.physicsBody.dynamic = NO;
[self addChild:self.anchor atWorldLayer:VZWorldLayerCharacter];


self.p_stick = [SKSpriteNode spriteNodeWithColor:[SKColor purpleColor] size:CGSizeMake(3, 50)];
self.p_stick.position = CGPointMake(_anchor.position.x, _anchor.position.y + _p_stick.frame.size.height/2);
self.p_stick.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:
                            CGSizeMake(_p_stick.frame.size.width, _p_stick.frame.size.height)];
self.p_stick.physicsBody.dynamic = NO;
self.p_stick.anchorPoint = CGPointMake(0, 0.5);
[self addChild:self.p_stick atWorldLayer:VZWorldLayerCharacter];

然后在触摸时我使游戏状态和更新方法正在进行：

SKAction *resize = [SKAction resizeByWidth:0 height:kVZStickHeight duration:timeSinceLast];
SKAction *move = [SKAction moveByX:0 y:kVZStickMove duration:timeSinceLast];
SKAction *group = [SKAction group:@[resize, move]];
[self.p_stick runAction:group];

然后我开始旋转，但是“y”总是会变高。

#define SK_DEGREES_TO_RADIANS(__ANGLE__) ((__ANGLE__) * 0.01745329252f)
CGPoint locationConv = [self convertPoint:location toNode:self.anchor]];
[self.p_stick runAction:[SKAction rotateByAngle:(atan2f(locationConv.y, SK_DEGREES_TO_RADIANS(-90)/*locationConv.x*/)) duration:1.0f]];

如何像关节销一样将销钉粘在平台上？

【问题讨论】：

标签： ios objective-c sprite-kit skspritenode anchorpoint

【解决方案1】：

首先设置锚点：

self.p_stick.anchorPoint = CGPointMake(0.5, 0);

您也可以为所有设置动态属性 NO。

你需要使用这个 atan2f 函数

(atan2f(SK_DEGREES_TO_RADIANS(90), SK_DEGREES_TO_RADIANS(0)))

【讨论】：