Camera refactored to use quaternions primarily for processing

rotations due to numerical reasons (no need for normalization
and orthogonalization of the rotation matrix).
This commit is contained in:
bubnikv 2020-02-28 13:29:05 +01:00
parent dff9af20a4
commit b6068b6278
2 changed files with 26 additions and 57 deletions

View File

@ -43,6 +43,7 @@ Camera::Camera()
, m_distance(DefaultDistance)
, m_gui_scale(1.0)
, m_view_matrix(Transform3d::Identity())
, m_view_rotation(1., 0., 0., 0.)
, m_projection_matrix(Transform3d::Identity())
{
set_default_orientation();
@ -85,7 +86,13 @@ void Camera::select_next_type()
void Camera::set_target(const Vec3d& target)
{
translate_world(target - m_target);
Vec3d new_target = validate_target(target);
Vec3d new_displacement = new_target - m_target;
if (!new_displacement.isApprox(Vec3d::Zero()))
{
m_target = new_target;
m_view_matrix.translate(-new_displacement);
}
}
void Camera::update_zoom(double delta_zoom)
@ -299,17 +306,6 @@ void Camera::debug_render() const
}
#endif // ENABLE_CAMERA_STATISTICS
void Camera::translate_world(const Vec3d& displacement)
{
Vec3d new_target = validate_target(m_target + displacement);
Vec3d new_displacement = new_target - m_target;
if (!new_displacement.isApprox(Vec3d::Zero()))
{
m_target += new_displacement;
m_view_matrix.translate(-new_displacement);
}
}
void Camera::rotate_on_sphere(double delta_azimut_rad, double delta_zenit_rad, bool apply_limits)
{
m_zenit += Geometry::rad2deg(delta_zenit_rad);
@ -324,49 +320,20 @@ void Camera::rotate_on_sphere(double delta_azimut_rad, double delta_zenit_rad, b
}
}
// FIXME -> The following is a HACK !!!
// When the value of the zenit rotation is large enough, the following call to rotate() shows
// numerical instability introducing some scaling into m_view_matrix (verified by checking
// that the camera space unit vectors are no more unit).
// See also https://dev.prusa3d.com/browse/SPE-1082
// We split the zenit rotation into a set of smaller rotations which are then applied.
static const double MAX_ALLOWED = Geometry::deg2rad(0.1);
unsigned int zenit_steps_count = 1 + (unsigned int)(std::abs(delta_zenit_rad) / MAX_ALLOWED);
double zenit_step = delta_zenit_rad / (double)zenit_steps_count;
Vec3d target = m_target;
translate_world(-target);
if (zenit_step != 0.0)
{
Vec3d right = get_dir_right();
for (unsigned int i = 0; i < zenit_steps_count; ++i)
{
m_view_matrix.rotate(Eigen::AngleAxisd(zenit_step, right));
}
}
if (delta_azimut_rad != 0.0)
m_view_matrix.rotate(Eigen::AngleAxisd(delta_azimut_rad, Vec3d::UnitZ()));
translate_world(target);
Vec3d translation = m_view_matrix.translation() + m_view_rotation * m_target;
auto rot_z = Eigen::AngleAxisd(delta_azimut_rad, Vec3d::UnitZ());
m_view_rotation *= rot_z * Eigen::AngleAxisd(delta_zenit_rad, rot_z.inverse() * get_dir_right());
m_view_matrix.fromPositionOrientationScale(m_view_rotation * (- m_target) + translation, m_view_rotation, Vec3d(1., 1., 1.));
}
void Camera::rotate_local_around_target(const Vec3d& rotation_rad)
{
rotate_local_around_pivot(rotation_rad, m_target);
}
void Camera::rotate_local_around_pivot(const Vec3d& rotation_rad, const Vec3d& pivot)
{
// we use a copy of the pivot because a reference to the current m_target may be passed in (see i.e. rotate_local_around_target())
// and m_target is modified by the translate_world() calls
Vec3d center = pivot;
translate_world(-center);
m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(0), get_dir_right()));
m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(1), get_dir_up()));
m_view_matrix.rotate(Eigen::AngleAxisd(rotation_rad(2), get_dir_forward()));
translate_world(center);
Vec3d translation = m_view_matrix.translation() + m_view_rotation * m_target;
auto rot_z = Eigen::AngleAxisd(rotation_rad(2), get_dir_forward());
auto rot_y = Eigen::AngleAxisd(rotation_rad(1), rot_z.inverse() * get_dir_up());
auto rot_x = Eigen::AngleAxisd(rotation_rad(0), rot_y.inverse() * get_dir_right());
m_view_rotation *= rot_z * rot_y * rot_x;
m_view_matrix.fromPositionOrientationScale(m_view_rotation * (-m_target) + translation, m_view_rotation, Vec3d(1., 1., 1.));
update_zenit();
}
@ -588,6 +555,9 @@ void Camera::look_at(const Vec3d& position, const Vec3d& target, const Vec3d& up
m_view_matrix(3, 2) = 0.0;
m_view_matrix(3, 3) = 1.0;
// Initialize the rotation quaternion from the rotation submatrix of of m_view_matrix.
m_view_rotation = Eigen::Quaterniond(m_view_matrix.matrix().template block<3, 3>(0, 0));
update_zenit();
}
@ -598,8 +568,8 @@ void Camera::set_default_orientation()
double phi_rad = Geometry::deg2rad(45.0);
double sin_theta = ::sin(theta_rad);
Vec3d camera_pos = m_target + m_distance * Vec3d(sin_theta * ::sin(phi_rad), sin_theta * ::cos(phi_rad), ::cos(theta_rad));
m_view_matrix = Transform3d::Identity();
m_view_matrix.rotate(Eigen::AngleAxisd(theta_rad, Vec3d::UnitX())).rotate(Eigen::AngleAxisd(phi_rad, Vec3d::UnitZ())).translate(-camera_pos);
m_view_rotation = Eigen::AngleAxisd(theta_rad, Vec3d::UnitX()) * Eigen::AngleAxisd(phi_rad, Vec3d::UnitZ());
m_view_matrix.fromPositionOrientationScale(m_view_rotation * (- camera_pos), m_view_rotation, Vec3d(1., 1., 1.));
}
Vec3d Camera::validate_target(const Vec3d& target) const

View File

@ -43,6 +43,8 @@ private:
mutable std::array<int, 4> m_viewport;
mutable Transform3d m_view_matrix;
// We are calculating the rotation part of the m_view_matrix from m_view_rotation.
mutable Eigen::Quaterniond m_view_rotation;
mutable Transform3d m_projection_matrix;
mutable std::pair<double, double> m_frustrum_zs;
@ -107,7 +109,7 @@ public:
#endif // ENABLE_CAMERA_STATISTICS
// translate the camera in world space
void translate_world(const Vec3d& displacement);
void translate_world(const Vec3d& displacement) { this->set_target(m_target + displacement); }
// rotate the camera on a sphere having center == m_target and radius == m_distance
// using the given variations of spherical coordinates
@ -117,9 +119,6 @@ public:
// rotate the camera around three axes parallel to the camera local axes and passing through m_target
void rotate_local_around_target(const Vec3d& rotation_rad);
// rotate the camera around three axes parallel to the camera local axes and passing through the given pivot point
void rotate_local_around_pivot(const Vec3d& rotation_rad, const Vec3d& pivot);
// returns true if the camera z axis (forward) is pointing in the negative direction of the world z axis
bool is_looking_downward() const { return get_dir_forward().dot(Vec3d::UnitZ()) < 0.0; }