void FaceModel::maybeUpdateNeckRotation(const JointState& parentState, const FBXJoint& joint, JointState& state) {
// get the rotation axes in joint space and use them to adjust the rotation
glm::mat3 axes = glm::mat3_cast(glm::quat());
glm::mat3 inverse = glm::mat3(glm::inverse(parentState.getTransform() * glm::translate(state.getDefaultTranslationInParentFrame()) *
joint.preTransform * glm::mat4_cast(joint.preRotation)));
state.setRotationInParentFrame(glm::angleAxis(- RADIANS_PER_DEGREE * _owningHead->getFinalRoll(), glm::normalize(inverse * axes[2]))
* glm::angleAxis(RADIANS_PER_DEGREE * _owningHead->getFinalYaw(), glm::normalize(inverse * axes[1]))
* glm::angleAxis(- RADIANS_PER_DEGREE * _owningHead->getFinalPitch(), glm::normalize(inverse * axes[0]))
* joint.rotation);
}
void FaceModel::maybeUpdateEyeRotation(const JointState& parentState, const FBXJoint& joint, JointState& state) {
// likewise with the eye joints
// NOTE: at the moment we do the math in the world-frame, hence the inverse transform is more complex than usual.
glm::mat4 inverse = glm::inverse(glm::mat4_cast(_rotation) * parentState.getTransform() *
glm::translate(state.getDefaultTranslationInParentFrame()) *
joint.preTransform * glm::mat4_cast(joint.preRotation * joint.rotation));
glm::vec3 front = glm::vec3(inverse * glm::vec4(_owningHead->getFinalOrientationInWorldFrame() * IDENTITY_FRONT, 0.0f));
glm::vec3 lookAt = glm::vec3(inverse * glm::vec4(_owningHead->getLookAtPosition() +
_owningHead->getSaccade() - _translation, 1.0f));
glm::quat between = rotationBetween(front, lookAt);
const float MAX_ANGLE = 30.0f * RADIANS_PER_DEGREE;
state.setRotationInParentFrame(glm::angleAxis(glm::clamp(glm::angle(between), -MAX_ANGLE, MAX_ANGLE), glm::axis(between)) *
joint.rotation);
}
