void gf_sg_set_scene_time_callback(GF_SceneGraph *sg, Double (*GetSceneTime)(void *user_priv))
{
	sg->GetSceneTime = GetSceneTime;
}
void gf_sg_set_scene_time_callback(GF_SceneGraph *sg, Double (*GetSceneTime)(void *user_priv))
{
	sg->GetSceneTime = GetSceneTime;
}