欧拉角到四元数然后四元数到欧拉角

I'm using lib glm (http://glm.g-truc.net/) for test quaternion but I've a problem; when I convert euler angle to quaternion then immediatly quaternion to euler angles, my result are totally different from my initial euler angles. Is this normal? Could it be because the rotations are not communative?

代码测试:

#include <glmquaternion.hpp>
#include <math.h>

#define PI M_PI
#define RADTODEG(x) ( (x) * 180.0 / PI )
#define DEGTORAD(x) ( (x) * PI / 180.0 )

int         main( void )
{
    float RotX = 90.f;
    float RotY = 180.f;
    float RotZ = -270.f;

    if ( RotX || RotY || RotZ )
    {
        std::cout << "Init: x= " << RotX << ", y= " << RotY << ", z= " << RotZ << "
";
        glm::quat key_quat(glm::detail::tvec3<float>(DEGTORAD( RotX ),
                                                     DEGTORAD( RotY ),
                                                     DEGTORAD( RotZ )));
        glm::detail::tvec3<float> v = glm::eulerAngles(key_quat);

        /*  // the result is even worse with this code here
        RotX = RADTODEG(v.x);
        RotY = RADTODEG(v.y);
        RotZ = RADTODEG(v.z);
        */

        RotX = v.x;
        RotY = v.y;
        RotZ = v.z;

        std::cout << "Final: x= " << RotX << ", y= " << RotY << ", z= " << RotZ << "
";
    }
    return (0);
}

结果:

Init: x= 90, y= 180, z= -270
Final: x= -90, y= -3.41509e-006, z= -90

提前谢谢你o/

推荐答案

是的，很正常.有两种方式可以用欧拉角表示相同的旋转.