181bf92086
Because Cogl defines the origin for texture as top left and offscreen draw buffers can be used to render to textures, we (internally) force all offscreen rendering to be upside down. (because OpenGL defines the origin to be bottom left) By forcing the users scene to be rendered upside down though we also reverse the winding order of all the drawn triangles which may interfere with the users use of backface culling. This patch ensures that we reverse the winding order for a front face (if culling is in use) while rendering offscreen so we don't conflict with the users back face culling.