thanks for the reply.
so if you put your begin/end/present in the main loop whats the problem?
well, as i said in my last post, maybe i don't complete understand the materials in the book. i took some computer classes for minor 20 year ago. i did not learn any thing about obj oriented programming. i am now self learning it now by myself. when i pass a string to a class to which represent as a puzzle to be animate. the puzzle is a 8's puzzle where one have 8 tile range from 1 - > 8 and move the tiles in a 3x3 board until one reach the goal state which is:
it is a first project that i write in my AI class. but i was text based and in this current program, i write it in graphics interface.
suppose i use breadth first search to find the solution and then i have to pass the solution to a class to animate the result. the text based program only takes about under 300 lines of code but the graphics interface one takes...you can guess.
so i have a input class where user can enter the original board (suppose the board to be solve is:
 this puzzle created ~2000000 nodes and takes 43 moves to get to the goal state
if there is a solution found, the user have the option to animate it(to see a sequence of moves until it reached it goal state).
the problem i have with oopl is that if i call a class to animate it, i have to pass all the graphics Images and coordinates to the class. in popl (procedural oriented programming language), it is in the scope. for my current program, my animate class does not know my input class's rendering method and my animate class have different graphics layout (it is like in a different levels) and i can not blit it in my animate class. so if it was SDL, i can blit it in my animate class and dont have to go back to beginScene/endScene/present methods to render it. i can blit it in my animate class and just have the sprite and coord imported from my board input class.
i hope i succeed in explain my predicament.
Edited by nickme, 01 August 2013 - 04:09 PM.