问题
The SCNNode take a rotation using a SCNVector4, which has an angle (w) and a magnitude how that angle applies to each axis (x, y, z). For example, to rotate 45 degrees around the x-axis I'd create a SCNVector4 like this:
SCNVector4Make(1.0f, 0, 0, DEG2RAD(45))
What I'd like to do is rotate it across all three axis, for example: 45 degrees on the x-axis, 15 degrees on the y-axis and -135 degress across the z-axis. Does anyone know the math to calculate the final SCNVector4?
回答1:
You'll need to generate an SCNVector4 for each of the rotations, and then multiply them. Note that the order of operations matters!
http://www.cprogramming.com/tutorial/3d/rotationMatrices.html has a pretty good writeup of the math. Any OpenGL reference that deals with rotation matrices is worth a look too.
回答2:
Instead of rotation property, use eulerAngles and specify angle for each axis
回答3:
If you're not animating the rotation, it might be cleaner to just set the transform matrix directly, like:
node.transform = CATransform3DRotate(CATransform3DRotate(CATransform3DRotate(node.transform, xAngle, 1, 0, 0), yAngle, 0, 1, 0), zAngle, 0, 0, 1);
回答4:
Do you ask for rotation matrix or how to simply rotate in general? If the second is correct then for example:
[node runAction:[SCNAction rotateByX:0 y:M_PI z:0 duration:0]];
来源：https://stackoverflow.com/questions/15776637/how-can-i-calculate-a-multi-axis-scnvector4-rotation-for-a-scnnode