enum {
     INIT,
     SDL_INIT,
     FINISH,
     VIEWER_RUN_INIT,
     VIEWER_RUN_LOOP,
     VIEWER_RUN_DRAW,
     VIEWER_RUN_FINISH,

     TASK_INIT_TEXTURE, 
     TASK_CREATE_SGP,
     TASK_UPDATE_SGP,
     TASK_CREATE_PP,
     TASK_CREATE_SPAN,
     TASK_CS_START,
     TASK_CS_RUN,
     TASK_DRAW_SPAN,
     TASK_DRAW_BACK,
     TASK_SET_TEXTURE,
     TASK_DUMMY,
};