如何正确旋转GLM四元数？

Question

我希望在我的游戏中将我的汽车向左旋转90度.

当我使用这段代码时:

            glm::quat rot(info.Rotation.w,info.Rotation.x,info.Rotation.y,info.Rotation.z);
            glm::quat done(glm::rotate(rot,glm::eulerAngles(rot)+glm::vec3(90.0f,0.0,0.0)));
            info.Rotation.x = done.x;
            info.Rotation.y = done.y;
            info.Rotation.z = done.z;
            info.Rotation.w = done.w;

汽车得到一个奇怪的旋转.

但是,以下代码根本不会改变汽车的旋转(正如我所期望的那样,只是为了确保GLM与游戏中的quats兼容):

            glm::quat rot(info.Rotation.w,info.Rotation.x,info.Rotation.y,info.Rotation.z);
            glm::quat done(rot);
            info.Rotation.x = done.x;
            info.Rotation.y = done.y;
            info.Rotation.z = done.z;
            info.Rotation.w = done.w;

每当我尝试检查旋转是否随之改变时:

            glm::quat rot(info.Rotation.w,info.Rotation.x,info.Rotation.y,info.Rotation.z);
            glm::quat done(glm::rotate(rot,vec3(0.0,0.0,0.0)));
            info.Rotation.x = done.x;
            info.Rotation.y = done.y;
            info.Rotation.z = done.z;
            info.Rotation.w = done.w;

汽车轮换仅设置为游戏中的0,0,0,0轮换.我希望这个代码保持旋转不受影响,因为我期望以下代码将汽车向左旋转90度:

            glm::quat rot(info.Rotation.w,info.Rotation.x,info.Rotation.y,info.Rotation.z);
            glm::quat done(glm::rotate(rot,vec3(90.0,0.0,0.0)));
            info.Rotation.x = done.x;
            info.Rotation.y = done.y;
            info.Rotation.z = done.z;
            info.Rotation.w = done.w;

但这不符合我的要求.它只是设置旋转,而不是将其添加到'rot'.

我究竟做错了什么？

Answer 1

如果您不关心万向节锁，那么这应该可行。

glm::quat rot(info.Rotation.w,info.Rotation.x,info.Rotation.y,info.Rotation.z);
glm::quat rot_euler_angles = glm::gtx::quaternion::eulerAngles(rot);
rot_euler_angles.x += 90;

glm::quat done(glm::rotate(rot,rot_euler_angles));
info.Rotation.x = done.x;
info.Rotation.y = done.y;
info.Rotation.z = done.z;
info.Rotation.w = done.w;

我认为这也是有效的

glm::vec3 rot(90.0*(float)M_PI/180.0, 0, 0);
info.Rotation = glm::normalize(info.Rotation * glm::quat(rot));

四元数非常棒，因为它们可以组合起来进行非常复杂的旋转。