I have some optimized level that doesn't contain any faces that player can't see. So if this level is rendered from outside, some walls will be invisible, because back faces are not drawn.
But it is a problem for sun, that is always outside. Back faces are not rendered to the shadow map, so they doesn't cast shadows. I tried to make material Double Sided, but it doesn't affect the shadow map rendering. Is there a way to render both faces to shadow map in godot 2.1.3?