iPhone 5s上的偏航范围

Question

我正在使用cmdevicemotion和态度的四元数来获取 titch 和 yaw 值，然后将其应用于Cocos3d场景中的CC3Camera以旋转相机。

#define RadiansToDegrees(x) ((180 / M_PI) * x)

- (void)initializeScene
{
    //...

    CC3Camera *cam = [CC3Camera nodeWithName:@"Camera"];
    cam.location = cc3v(0, 10, 0.0001);
    cam.targetLocation = cc3v(0, 0, 0);
    _cameraBoom = [CC3Node nodeWithName:@"CameraBoom"];
    _cameraBoom.location = cc3v(0, 0, 0);
    [_cameraBoom addChild:cam];
    [self addChild:_cameraBoom];
    [self setActiveCamera:cam];
    _cameraBoom.rotation = cc3v(0, 90, 0);

    //...

    _motionManager = [[CMMotionManager alloc] init];
    _referenceAttitude = nil;
    _initialCameraRotation = _cameraBoom.rotation;

    [self enableMotion];
}

- (void)enableMotion
{
    CMDeviceMotion *deviceMotion = _motionManager.deviceMotion;
    _referenceAttitude = deviceMotion.attitude;
    _initialCameraRotation = _cameraBoom.rotation;

    [_motionManager startDeviceMotionUpdates];

    if (!_gyroTimer) {
        _gyroTimer = [NSTimer scheduledTimerWithTimeInterval:1 / 30.0
                                                      target:self
                                                    selector:@selector(doGyroUpdate)
                                                    userInfo:nil
                                                     repeats:YES];
    }
}

- (void)doGyroUpdate
{
    CMDeviceMotion *deviceMotion = _motionManager.deviceMotion;
    CMAttitude *attitude = deviceMotion.attitude;

    if (_referenceAttitude != nil) {
        [attitude multiplyByInverseOfAttitude:_referenceAttitude];
    }

    CMQuaternion quat = attitude.quaternion;
    double pitch = RadiansToDegrees(atan2(2 * (quat.x * quat.w + quat.y * quat.z), 1 - 2 * (quat.x * quat.x + quat.z * quat.z)));
    double yaw = RadiansToDegrees(asin(2 * (quat.x * quat.y + quat.w * quat.z)));

    _cameraBoom.rotation = CC3VectorAdd(_initialCameraRotation, cc3v(pitch, yaw, 0));
}

.

间距在范围内[-π，π]。当设备面向音高= 0时，当我从表中取出设备并指向图片（纵向模式）时，它变为π/ 2。 [-π，π]范围使我能够旋转装置360°。当面对（即设备颠倒）时，音调值是π。

偏航范围仅是[-π/ 2，π/ 2]。当我将设备旋转到左侧时，它从0开始，然后进入π/ 2。但是如果我超越π/ 2，则偏航值开始减少。

我可以获得范围[-π，π]的偏航值，就像音调？能够侧向将相机侧向旋转180°（向左右侧，要有一个完整的360°视图）而不是将器件垂直翻转以与相机一起看。

Answer 1

这是我最终用内置函数所做的方式如何：

- (void)doGyroUpdate
{
    CMDeviceMotion *deviceMotion = _motionManager.deviceMotion;
    CMAttitude *attitude = deviceMotion.attitude;

    if (_referenceAttitude != nil) {
        [attitude multiplyByInverseOfAttitude:_referenceAttitude];
    }

    CMQuaternion quat = attitude.quaternion;
    CC3Quaternion cc3Quat = CC3QuaternionMake(quat.x, quat.y, quat.z, quat.w);
    CC3Vector rot = CC3RotationFromQuaternion(cc3Quat);

    _cameraBoom.rotation = cc3v(-rot.x, -rot.z, rot.y);
}

.

结果：

旋转相机，使您能够在Skybox上环顾四周，仿佛通常通过设备的背部相机查看世界。我的cc3camera对象位于一个球体内，映射到它的hdri映像，在内部（参见这个帖子）。

要平滑旋转相机：

[_cameraBoom runAction:[CC3ActionRotateTo actionWithDuration:0.15 rotateTo:cc3v(-rot.x, -rot.z, rot.y)]];

.

希望这也有助于别人。