constant refresh

This is a discussion on constant refresh within the Game Programming forums, part of the General Programming Boards category; right now I am working a space invaders type game. The initial screen is read from a text file that ...

  1. #1
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    constant refresh

    right now I am working a space invaders type game. The initial screen is read from a text file that looks like

    1111111111111114
    1000000000000014
    1000000000000014
    1000000000000014
    1000000000000014
    1000000000000014
    1000000300000014
    1000000000000014
    1111111111111114

    then I load it into a two dimensional array called screen [ ] [ ]

    then I run a switch statement

    Code:
    switch ( screen [ ] [ ] )
    {
    case 1: 
    printf ("*");               // wall barrier
    break;
    
    case 0: 
    printf (" ");                // open space
    break;
    
    case 3:
    printf ("X");               // users ship
    break;
    
    case 4:
    printf ("\n");
    break;
    }
    Then I have some movment controls and colision detection controls. Mind you this entire program is under a while loop and is always in constant refresh. As my program is getting bigger I noticed my screen is starting to blink. I realized this is because my program is constantly checking values, and redrawing the screen.

    My theory is to only refresh the screen every one half second and force another screen refresh if an event happens (ie: my ship moves)

    would that be sufficent enough so that my screen wouldnt look so... choppy?

  2. #2
    Kernel hacker
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    The other option is of course to only update sections of the screen that has changed - it requires that you use some function to do "gotoxy()" and probably some heuristics to figure out if "most things have changed, so redraw the whole thing".

    --
    Mats

  3. #3
    Registered User mmarab's Avatar
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    Wouldnt page flipping or double buffering help solves this problem. Or am i going way off target. Anyway just trying to help.

  4. #4
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    I like the update only part of the screen idea. But its all in text, so I would have to use \b and as far as i know that only works if your on the current line. And that could get very messy very fast. Maybe I will just live with the blinking screen. I just might have to add a seizure warning heh

  5. #5
    Super Moderator VirtualAce's Avatar
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    You need double buffering or page flipping. And most likely you would want to move to a graphics API to do this.

  6. #6
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    look at the ncurses library, the provide gotoxy for terminal. there is also a windows port out there

  7. #7
    Registered User IdioticCreation's Avatar
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    Well, I would also recommend a graphics API, but since all the stuff is stored into an array you don't need to worry about the text file once it loaded. Actually I don't even get the purpose of the text file. Say if the users ship moved to the left then you can change the ships current location in the array to a "0" and -1 of it's position to the "X" then +1 to go right. For movement up and down you could add or subtract the number in each row of your array.

    As far as refreshing, I don't have much help.

  8. #8
    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    I second ncurses, not because it provides gotoxy() (it doesn't actually, the function is move() ), but because ncurses takes into account what's already there.
    From the ncurses man pages:
    The routine wrefresh copies the named window to the physical terminal screen, taking into account what is already there to do optimizations. The refresh routine is the same, using stdscr as the default window.
    ncurses is also available on several platforms (if you're using Windows, google for pdcurses), and so allows your program to be portable.
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