Rift. If you say it's implemented then it's possible I must be bypassing it. Using C++ only and a bare map, terrain, a cockpit model and a directional light. No post processing filters or anything. If those are required I'll give it another go, but I didn't read anything that suggested otherwise. Screenshot of mirror display attached.
int main(const int argc,const char *argv[])
{
Leadwerks::Window* window = Leadwerks::Window::Create("VR Test", 0, 0, 1024, 768, Window::Titlebar);
Context* context = Context::Create(window);
World* world = World::Create();
Camera* camera = Camera::Create();
VR::Enable();
Map::Load("Maps/start.map");
...
...
}