iOS平台使用陀螺仪传感器

在移动端开发过程中，有时候会用到陀螺仪传感器获取当前手机的姿态，下面给出iOS端如何获取陀螺仪姿态数据的代码：

 //根据陀螺仪的四元数转换为矩阵
 + (GLKMatrix4)calculateMatrixFromQuaternion:(CMQuaternion*)quaternion orientation:(AVCaptureVideoOrientation) orientation{
     float xx = quaternion->x * quaternion->x;
     float yy = quaternion->y * quaternion->y;
     float zz = quaternion->z * quaternion->z;
     float xy = quaternion->x * quaternion->y;
     float wz = quaternion->w * quaternion->z;
     float wy = quaternion->w * quaternion->y;
     float xz = quaternion->x * quaternion->z;
     float yz = quaternion->y * quaternion->z;
     float wx = quaternion->w * quaternion->x;

     float r00 =  -  * (yy + zz);
     float r01 =  * (xy - wz);
     float r02 =  * (wy + xz);
     float r03 = ;

     float r10 =  * (xy + wz);
     float r11 =  -  * (xx + zz);
     float r12 =  * (yz - wx);
     float r13 = ;

     float r20 =  * (xz - wy);//xy - wy
     float r21 =  * (yz + wx);
     float r22 =  -  * (xx + yy);
     float r23 = ;

     float r30 = ;
     float r31 = ;
     float r32 = ;
     float r33 = ;

     return GLKMatrix4Make(r00,r01,r02,r03,
                       r10,r11,r12,r13,
                       r20,r21,r22,r23,
                       r30,r31,r32,r33);
 }

 //当前屏幕的方向
 @property (nonatomic, readwrite, assign) AVCaptureVideoOrientation orientation;
 //开启陀螺仪
 - (void)updateAngleFromAttitudeSensor{
     if(self.cmmotionManager){

     }else{
         self.cmmotionManager = [[CMMotionManager alloc] init];
         self.cmmotionManager.deviceMotionUpdateInterval = 1.0/25.0;
         self.cmmotionManager.gyroUpdateInterval = 1.0/25.0;
         self.cmmotionManager.showsDeviceMovementDisplay = YES;

         NSOperationQueue *mQueue = [[NSOperationQueue alloc]init];
         __weak typeof(self) wSelf = self;
         [wSelf.cmmotionManager startDeviceMotionUpdatesToQueue:mQueue withHandler:^(CMDeviceMotion * _Nullable motion, NSError * _Nullable error){
             CMAttitude *attitude = motion.attitude;
             if (attitude == nil) {
                 return;
             }

             //UID
             CMQuaternion quaternion = attitude.quaternion;
             wSelf.sensorMatrix = GLKMatrix4Identity;
             wSelf.sensorMatrix = [GyroscopeUtil calculateMatrixFromQuaternion:&quaternion orientation:orientation];

             wSelf.sensorMatrix = GLKMatrix4RotateX(wSelf.sensorMatrix,M_PI_2);
             wSelf.sensorInverseMatrix = GLKMatrix4Identity;

             bool isInvertible = true;
             wSelf.sensorInverseMatrix = GLKMatrix4Invert(wSelf.sensorMatrix, &isInvertible);
         }];
     }
 }