C++/SDL Clear Surface?

[Ryan Wilson]

Hey everyone I was wondering how I would clear a surface from the screen with SDL.

Here is my CGame class which runs the core function of the game. I wrote the Tic Tac Toe game really sloppy but I will be improving this later, wrote this in like 10 minutes. Wouldn't let me post my whole class to big sorry everyone

Here is where I want to reset the game board surface

if (event->button.button == SDL_BUTTON_LEFT)
        {
            if (won == true) // If game is over reset game on click
            {
                // RESET BOARD
                board[0] = 0;
                board[1] = 0;
                board[2] = 0;
                board[3] = 0;
                board[4] = 0;
                board[5] = 0;
                board[6] = 0;
                board[7] = 0;
                board[8] = 0;

                //clear X surface's
                //clear O surface's
                //and update game board

                won = false;
            }
}

[helios]

Just overwrite the screen surface with black, what's the problem?

[Ryan Wilson]

When I do:
SDL_FillRect(background, NULL, SDL_MapRGB(screen->format, 0, 0, 0));
It fills it over my Tic Tac Toe background grid surface

[Peter87]

So draw your "Tic Tac Toe background grid" again.

[Ryan Wilson]

It worked thanks Peter87 :D Should I set background NULL then load the image back to it? It works either way just curious on what I should do.

 //clear X surface's
                //clear O surface's
                //and update game board
                background = NULL;
                background = CResourceManager::loadImage("background.png", false);
                CResourceManager::applySurface(background, screen);

 //clear X surface's
                //clear O surface's
                //and update game board
                background = CResourceManager::loadImage("background.png", false);
                CResourceManager::applySurface(background, screen);

[Peter87]

Haven't you loaded the background image already? No point doing that again. Just draw the background on to the screen.
CResourceManager::applySurface(background, screen);

[helios]

If background was already pointing to the loaded PNG, why would you load the PNG again?

[Ryan Wilson]

It only works if I reload the image with my loadImage function. If I just draw it to the screen again it doesn't clear the background of the X's and O's.

[Ryan Wilson]

In my render function I have it like this:

void CGame::render()
{
    CResourceManager::applySurface(background, screen);

    SDL_Flip(screen);
}

So if I load the background surface to the old background image it clears it and don't need to draw it again cause i'm looping through it in my main class.

[Peter87]

It sounds like you have drawn the X's and O's to the background. Draw them to the screen instead.

[Ryan Wilson]

When I draw them to the screen they don't show up. If I draw them to the background it does.

[Peter87]

Did you draw them in the right order? First the background, then the X's and O's.

[helios]

That's because you're drawing the background over them. Either draw the background just once, or draw the background and every X and O in every frame.