SceneKit中的相机旋转

我已经发布了类似的问题，这在这里，但是这是因为它与EULAR角度涉及不同。

鉴于我在另一篇文章中所做的设置。屏幕上有一个简单的板子，还有一个看着它的相机，我想旋转相机。为简单起见，我将用代码编写整个摄像机。就上下文而言，根据其他问答，我确定板子在Z轴上运行的时间较长，在X轴上运行的时间较短，而高度在Y轴上。

将此代码添加到场景中，我们可以看到我的电路板在Z轴上运行。我将相机在Y轴上稍微抬起，以获得更好的视野。我的最终目标是使电路板在摄像机上长期运行。

SCNNode *cameraNode = [SCNNode node];
cameraNode.camera = [SCNCamera camera];
cameraNode.camera.zFar = 200;
cameraNode.camera.zNear = 0.1;
[scene.rootNode addChildNode:cameraNode];
cameraNode.position = SCNVector3Make(0, 5, 0);
cameraNode.eulerAngles = SCNVector3Make(0, 0, 0);

给

很好的开始。然后，我尝试旋转相机，使其从顶部向下看向木板。我的理解是，我需要绕X轴旋转才能完成此操作。我通过尝试以下方法来做到这一点。

SCNNode *cameraNode = [SCNNode node];
cameraNode.camera = [SCNCamera camera];
cameraNode.camera.zFar = 200;
cameraNode.camera.zNear = 0.1;
[scene.rootNode addChildNode:cameraNode];
cameraNode.position = SCNVector3Make(0, 50, 0);
cameraNode.eulerAngles = SCNVector3Make(0, 0, -M_PI/2);

iOS文档指出以（z，y，x）设置欧拉的旋转。但是，这没有用，只能显示空白屏幕。然后，我开始进行实验，发现绕Z轴旋转将使我朝正确的方向前进。

SCNNode *cameraNode = [SCNNode node];
cameraNode.camera = [SCNCamera camera];
cameraNode.camera.zFar = 200;
cameraNode.camera.zNear = 0.1;
[scene.rootNode addChildNode:cameraNode];
cameraNode.position = SCNVector3Make(0, 50, 0);
cameraNode.eulerAngles = SCNVector3Make(-M_PI/2, 0, 0);

这呈现了此屏幕。

这没有任何意义，但我继续进行下去，最终发现通过围绕Y轴旋转，我可以获得所需的屏幕。

SCNNode *cameraNode = [SCNNode node];
cameraNode.camera = [SCNCamera camera];
cameraNode.camera.zFar = 200;
cameraNode.camera.zNear = 0.1;
[scene.rootNode addChildNode:cameraNode];
cameraNode.position = SCNVector3Make(0, 50, 0);
cameraNode.eulerAngles = SCNVector3Make(-M_PI/2, -M_PI/2, 0);

The y rotation was also a little baffling because I would have expected to have to rotate around the Z axis.

While this code works I have a similar question to my other post. Why do I have to rotate around the Z axis instead of the X axis for my first rotation. I think I might just not understand eular angles that well.

Thanks in advance

Edit:

as @mnuages pointed out, the documentation online states that this vector is in (x,y,z). This is contrary to the header documentation which I would normally use as can be seen here

It would appear that this is just a bug/typo in Apple's code. Thanks for clearing it up.