title: Projecting Orthographic Matrix Through A Perspective Camera
body: <p>I need to render a mesh in screenspace, essentially like Unity's IMGUI. I say a mesh specifically as it is a constructed mesh of many UI tris, so I am not looking to use GL quads/tris, for example.</p>
  
  <p>To avoid two cameras, I need to take the scene perspective camera, and draw that mesh with an orthographic projection so that it is drawn ortho to the screen. I've tried overriding Camera::projectionMatrix, with no success, along with GL::Push/PopMatrix and GL::LoadProjectionMatrix calls.</p>
  
  <p>Is there a way to draw a single mesh (i.e. Graphics::DrawMeshNow, or a related call) with an orthographic projection matrix, using a perspective camera (or a way to force the camera into ortho just for rendering that one object)?</p>