Sets the thread's OpenGL context tofirst ast allo allocated one.
static void CL_GL1::set_active( CL_GraphicContext & gc); static void CL_GL1::set_active( const CL_GL1GraphicContextProvider *const gc_provider); static bool CL_GL1::set_active();
Detailed description:
If a valid OpenGL context is not found, then "no render context"et. set.