NVidia Physx Get Orientation problem

Question

For a game that I am developing I moved from Bullet physics to NVidia Physx. The problem that I have is the following. I used to have a translation from bullet's rigid body orientation quaternion to Front , Right and Up vector for each object on the screen. This was working fine but after I moved to Physx I noticed that there is only one quaternion in the transform of the object (probably representing rotation) and no orientation quaternion. Here is the code that I was using in Bullet to get the 3 vectors translated to Physx :

physx::PxQuat ori = mBody->getGlobalPose().q;

auto Orientation = glm::quat(ori.x, ori.y, ori.z, ori.w);

glm::quat qF = Orientation * glm::quat(0, 0, 0, 1) * glm::conjugate(Orientation);
glm::quat qUp = Orientation * glm::quat(0, 0, 1, 0) * glm::conjugate(Orientation);
front = { qF.x, qF.y, qF.z };
up = { qUp.x, qUp.y, qUp.z };
right = glm::normalize(glm::cross(front, up));

This apparently doesn't work for Physx. Is there another way to retrieve the 3 vectors from the rigid body ?

Answer 1

Based on this line:

glm::quat qF = Orientation * glm::quat(0, 0, 0, 1) * glm::conjugate(Orientation);

It looks like glm::quat() is taking arguments in the order w, x, y, z (ie. real component first, then the three imaginary components), so that glm::quat(0, 0, 0, 1) represents a pure imaginary quaternion (a 3D vector) pointing along the z+ axis.

But this line puts w last instead of first:

auto Orientation = glm::quat(ori.x, ori.y, ori.z, ori.w);

This should probably be like this instead, to match the convention used elsewhere in your code:

auto Orientation = glm::quat(ori.w, ori.x, ori.y, ori.z);