swift – 如何在SceneKit中移动旋转的SCNNode？

解决方法@H_673_22@

所以我的理解是你想要沿着它自己的X轴移动Box节点(而不是它的父X轴).并且因为Box节点被旋转,其X轴未与其父节点对齐,因此您在转换两个坐标系之间的平移时遇到问题.

节点层次结构是

parentNode
    |
    |----BoxNode // rotated around Y (vertical) axis

使用转换矩阵

沿自己的X轴移动BoxNode

// First let's get the current BoxNode transformation matrix
SCNMatrix4 BoxTransform = BoxNode.transform;

// Let's make a new matrix for translation +2 along X axis
SCNMatrix4 xTranslation = SCNMatrix4MakeTranslation(2,0);

// Combine the two matrices,THE ORDER MATTERS !
// if you swap the parameters you will move it in parent's coord system
SCNMatrix4 newTransform = SCNMatrix4Mult(xTranslation,BoxTransform);

// Allply the newly generated transform
BoxNode.transform = newTransform;

请注意：当矩阵相乘时,顺序很重要

另外一个选项：

使用SCNNode坐标转换功能,看起来更直接

// Get the BoxNode current position in parent's coord system
SCNVector3 positionInParent = BoxNode.position;

// Convert that coordinate to BoxNode's own coord system
SCNVector3 positionInSelf = [BoxNode convertPosition:positionInParent fromNode:parentNode];

// Translate along own X axis by +2 points
positionInSelf = SCNVector3Make(positionInSelf.x + 2,positionInSelf.y,positionInSelf.z);

// Convert that BACk to parent's coord system
positionInParent = [parentNode convertPosition: positionInSelf fromNode:BoxNode];

// Apply the new position
BoxNode.position = positionInParent;