在 Libgdx 中旋转四元数

Question

我们如何在 libgdx 中围绕某个轴旋转四元数？

var rotation = new Quaternion().setEulerAngles(0.0f, 0.0f, 90.0f);
// How do we rotate that quaternion around X axis 90 degrees ?

Answer 1

旋转四元数意味着：将另一个四元数乘以原始四元数的右侧或左侧（取决于您要旋转的空间）。 例如，如果您希望向量先绕 X 轴旋转 90 度，然后绕 Z 轴旋转 90 度，则可以使用以下代码实现：

// your quaternion (rotation of 90 degrees around Z axis)
Quaternion rotation = new Quaternion().setEulerAngles(0, 0, 90);
// quaternion expressing rotation of 90 degrees around X axis
Quaternion x90deg = new Quaternion().setEulerAngles(0, 90, 0);
// concatenation (right-multiply) of the X rotation with the Z rotation
Quaternion result = new Quaternion(rotation).mul(x90deg);
// test: rotate (0, 0, 1) around X axis 90 deg, followed by Z axis 90 deg
// the first rotation will yield (0, -1, 0), and the second rotation (1, 0, 0) as a result
Vector3 v = new Vector3(0, 0, 1);
result.transform(v);
// v = (1, 0, 0)