+// we have all the OpenGL extensions we need. Returns true if initialization
+// succeeded.
+//
+// The first parameter gives which directory to read .frag files from.
+// This is a temporary hack until we add something more solid.
+//
+// The second parameter specifies whether debugging is on or off.
+// If it is on, Movit will write intermediate graphs and the final
+// generated shaders to the current directory.
+//
+// If you call init_movit() twice with different parameters,
+// only the first will count, and the second will always return true.
+bool init_movit(const std::string& data_directory, MovitDebugLevel debug_level) MUST_CHECK_RESULT;