Question

我正在尝试旋转我的对象（SCNNode）以面对它正在移动的点。我只穿过x和y轴，到目前为止我试过了：

    // Action to move node
    let action1 = SCNAction.moveTo(SCNVector3(x: 4.0, y: 0.0, z: 6.0), duration: 3)
    // Get the tan angle:
    let angle = CGFloat(atan2(z, x))
    if angle - previousAngle > Pi {
        playerAngle += 2 * Pi
    } else if previousAngle - angle > Pi {
        playerAngle -= 2 * Pi
    }
    previousAngle = angle
    playerAngle = angle * RotationBlendFactor + playerAngle * (1 - RotationBlendFactor)
    let rot = playerAngle - 90 * DegreesToRadians
    flyNode.rotation = SCNVector4(x: 0, y: 1, z: 0, w: Float(rot))

它适用于某些目标点，但不适用于所有目标点。

我也尝试添加约束数组SCNLookAtConstraint，它完美地旋转我的节点，但它停止我移动到动画：

    let targerNode = SCNNode()
    targerNode.position = SCNVector3(x: -4.0, y: 0.0, z: -2.0)
    let con = SCNLookAtConstraint(target: targerNode)
    flyNode.constraints = [con]        
    let action1 = SCNAction.moveTo(SCNVector3(x: 4.0, y: 0.0, z: -2.0), duration: 3)

你能帮我解决这个问题吗？

Answer 1

最简单的解决方案（尽管可能不是最优雅的）是将moveTo SCNAction应用于节点，并将SCNLookAtConstraint应用于该节点的子节点。这应该使两者都能在没有冲突的情况下运作。

Answer 2

尝试使用:(它是客观的C，但它应该很容易转换）

float x, z;// these are your vars you assign these so you can delete this line


float offset = 0; // use this to offset your final output
                  // because your output might be off by 
                  // a quarter of a turn or so, or more
                  // but once you got the offset right
                  // than it will stay right
float aQuarterOfAturn = 1.570795;// since scenekit uses radians
                                 // this needs to be pi/2
                                 // if it was degrees it would be 90


if (x < 0) {
    offset += aQuarterOfAturn;// turn it to compensate for the lack of negetive x
    x *= -1;// convert x to positive so we can calculate it
}
if (z < 0) {
    offset += aQuarterOfAturn;// turn it to compensate for the lack of negetive z
    z *= -1;// convert z to positive so we can calculate it
}

xzDelta = x + z// add x and z

zPercent = z * 100 / xzDelta // so we can calculate how much percent z is

yRot = aQuarterOfAturn * zPercent / 100 // and finally convert it to a rotation

yRot += offset // add the offset and you can implement the rotation now
// a note, this code has not been tested you may need to offset it (above)
// and possibly multiply it by negitive 1

// if it works fine but the rotation is off by however many degrees than just offset it

// if it works fine but your move up and it rotates down than multiply it by -1

让我知道它是如何运作的！

将SCNNode旋转到面向点

2 个答案: