message: fix a arithmetic error in SSR when a symmetry was present
  Make sure that Camera returns a positive field-of-view, even when
  the projection matrix has a symmetry (negative scaling).
diff: @@ -114,12 +114,13 @@ public:
  }
  float getFieldOfView(Camera::Fov direction) const noexcept {
  + // note: this is meaning less for an orthographic projection
  auto const& p = getProjectionMatrix();
  switch (direction) {
  case Fov::VERTICAL:
  - return 2.0f * std::atan(1.0f / float(p[1][1]));
  + return std::abs(2.0f * std::atan(1.0f / float(p[1][1])));
  case Fov::HORIZONTAL:
  - return 2.0f * std::atan(1.0f / float(p[0][0]));
  + return std::abs(2.0f * std::atan(1.0f / float(p[0][0])));
  }
  }
  